{"id":9167,"date":"2022-12-04T10:36:04","date_gmt":"2022-12-04T15:36:04","guid":{"rendered":"https:\/\/dronebotworkshop.com\/?p=9167"},"modified":"2023-04-05T14:14:28","modified_gmt":"2023-04-05T18:14:28","slug":"mecanum","status":"publish","type":"post","link":"https:\/\/dronebotworkshop.com\/mecanum\/","title":{"rendered":"Mecanum Wheel Robot Car with ESP-NOW Remote Control"},"content":{"rendered":"\n<p><a href=\"https:\/\/s3.amazonaws.com\/download.dronebotworkshop.com\/DBWS+-+PDF+-+Mecanum+Wheel+Robot+Car+with+ESP-NOW+Remote+Control.zip\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-9571 size-full\" title=\"Download PDF\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/04\/dbws-pdfdown.png?resize=64%2C64&#038;ssl=1\" alt=\"Download PDF\" width=\"64\" height=\"64\" data-recalc-dims=\"1\" \/><\/a> <a href=\"#Parts_List\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-9563 size-full\" title=\"Parts List\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/04\/dbws-parts.png?resize=64%2C64&#038;ssl=1\" alt=\"Parts List\" width=\"64\" height=\"64\" data-recalc-dims=\"1\" \/><\/a> <a href=\"https:\/\/youtu.be\/dZttHOxIoek\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-9565 size-full\" title=\"View on YouTube\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/04\/dbws-youtube.png?resize=64%2C64&#038;ssl=1\" alt=\"View on YouTube\" width=\"64\" height=\"64\" data-recalc-dims=\"1\" \/><\/a> <a href=\"https:\/\/s3.amazonaws.com\/download.dronebotworkshop.com\/Mecanum+Wheel+Car-DroneBot+Workshop.zip\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-9569 size-full\" title=\"Download Code\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/04\/dbws-codedown.png?resize=64%2C64&#038;ssl=1\" alt=\"Download Code\" width=\"64\" height=\"64\" data-recalc-dims=\"1\" \/><\/a><\/p>\n<p><span style=\"font-weight: 400;\">Today we will build a robot car with a difference &#8211; in the wheels, anyway. Mecanum wheels are unique because they can propel a vehicle in any direction, not just forwards or backward.<\/span><\/p>\n<div class=\"youtube-player\" data-id=\"dZttHOxIoek\"><\/div>\n<p><span style=\"font-weight: 400;\">Driving a vehicle with Mecanum wheels is different from standard wheels, and today we\u2019ll see exactly how to do that.\u00a0 We\u2019ll build a robot car that uses an ESP32, one featuring a remote control that uses another ESP32.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Introduction<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">When we design a simple robot or \u201crobot car,\u201d we need to choose a steering method. There are a couple of popular choices:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Skid Steering &#8211; Probably the most popular for robot cars, with skid steering two wheels are used. By changing the speed and direction of each wheel, the robot car can be steered in any direction.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Standard Steering &#8211; This is the type of steering commonly used in automobiles, when used with cars and trucks, it can also be called rack and pinion steering. With this type of steering, the front (or all 4) wheels are moved in tandem to change their direction of travel. When used with small models and robot cars, the front wheels can be moved using a servo or stepper motor.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Today we will build a robot car using a third choice &#8211; Mecanum Wheels.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Mecanum Wheels<\/span><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9205\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Mecanum wheels were invented in 1972 by Swedish engineer Bengt Erland Ilon, who worked for a design firm named Mecanum AB.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Mecanum wheels are omnidirectional wheels, they can be used to propel a vehicle in any direction.\u00a0 Instead of tires, they have a series of rubberized external rollers mounted at 45-degree angles around the wheel&#8217;s circumference.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Mecanum Wheels need to be used in groups of four or more to allow omnidirectional movement, although you can achieve some control using just three wheels.\u00a0<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9190\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-2-types.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-2-types.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-2-types.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">The rollers on these wheels can be oriented in two different directions, and you need two of each type for complete control.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One set of wheels has the rollers mounted at a 45-degree angle to the axle.\u00a0 The other type uses rollers mounted at a 45-degree angle to the plane of the wheel.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">These four wheels (two of each type) are mounted on the robot car chassis as shown here:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9188\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheel-arrangement.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheel-arrangement.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheel-arrangement.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">By mounting the wheels in this manner, we can move the vehicle in six different directions.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Move Straight<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">In this mode, our Mecanum Wheel vehicle operates just like a standard robot car. We can go forwards or backward by alternating the direction we spin the wheels.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9196\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-straight.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-straight.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-straight.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This mode has all four wheels driven in the same direction and at the same speed.\u00a0<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Move Sideways<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">By spinning the wheels on each side in opposite directions and reversing the order between sides, we can make our vehicle move sideways.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9195\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-sideways.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-sideways.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-sideways.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Reversing the directions of all four motors will cause the vehicle to go sideways in the opposite direction.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Move Diagonally<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">To move diagonally, we only use two motors, ones on opposite corners that have the same wheel roller orientation.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9191\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-diagonal.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-diagonal.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-diagonal.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Changing the direction of rotation will cause the vehicle to move at the same angle but in the opposite direction.\u00a0 Using the other two Mecanum wheels will cause the vehicle to travel diagonally as well, 90 degrees opposite to the original configuration.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Pivot (on one side)<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Running two wheels on the same side of the vehicle in the same direction will cause it to pivot.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9193\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Reversing the rotation of the wheels will make the vehicle pivot in the opposite direction, and using the wheels on the other side of the vehicle will cause it to pivot on the other side.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Rotate<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">By spinning the wheels on one side of the chassis in one direction and the ones on the other side in the opposite direction, we can make the vehicle rotate.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9194\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-rotate.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-rotate.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-rotate.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This is the same operation as a standard 4-wheel robot car. Reversing the direction of wheel rotation will cause the car to spin in the opposite direction.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Pivot Sideways<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The final Mecanum wheel movement is a variation of the Pivot. This is the Pivot Sideways, which works in the same fashion but uses two wheels on the same axle, as opposed to on the same side.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9192\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot-sideways.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot-sideways.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels-pivot-sideways.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Once again, reversing the direction of wheel rotation will reverse the pivot direction.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Testing Mecanum Wheels<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">All that theory is fine, but the real fun is putting it to the test.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">To do that, I installed the motors and wheels onto the bottom plate of the chassis that I purchased (my chassis has a lower and upper section). I didn\u2019t do a complete assembly, and I didn\u2019t even remove the plastic film from the chassis, as this is just a temporary test.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I also put the chassis \u201cup on blocks,\u201d meaning that I took a couple of scraps of wood to raise it above my workbench. Didn\u2019t want it running all over the place while I tested it!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">After I did a few tests up on blocks, I wanted to see how it ran on the floor &#8211; watching wheels move is interesting, but the real fun comes in watching it actually go through the maneuvers on the ground. To accomplish this, I extended the connections between my motor and my solderless breadboard by using a flexible Ethernet cable.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">ESP32 Motor Hookup<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Four motors mean four motor drivers, and the TB6612FNG is the obvious choice.\u00a0 Its MOSFET design is vastly superior to the old L298N dual motor driver, plus it is a lot smaller.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I hooked up the drivers and motors as follows:<\/span><\/p>\n<figure id=\"attachment_9169\" aria-describedby=\"caption-attachment-9169\" style=\"width: 768px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/03\/ESP32-Motor-Hookup-Large.jpg?ssl=1\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9169 size-full\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/ESP32-hookup-car.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/ESP32-hookup-car.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/ESP32-hookup-car.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-9169\" class=\"wp-caption-text\">Click on the wiring diagram to open a larger image<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">The \u201cMotor Power\u201d will, of course, depend upon which motors you are using. The small yellow motors commonly supplied with \u201crobot car bases\u201d generally like 6 to 9 volts as a power supply, and for my tests, I used a 6-volt battery pack.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Simple Motor Test Sketch<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">To test the motors, I used a very simple sketch.<\/span><\/p>\n<pre class=\"lang:default decode:true\" title=\"4wd-test.ino\">\/*\r\n  4WD Mecanum Wheel Robot Car Base - Motor Test\r\n  4wd-test.ino\r\n  Cycles all 4 Mecanum wheels to verify proper operation\r\n  Uses ESP32 DevKitC (other ESP32 boards will work)\r\n  Uses 2 TB6612FNG Motor Drivers, also compatible with L298N\r\n  \r\n  DroneBot Workshop 2022\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"NkQQeQAbCA\"><a href=\"https:\/\/dronebotworkshop.com\/\">Welcome to the Workshop!<\/a><\/blockquote><iframe class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" title=\"&#8220;Welcome to the Workshop!&#8221; &#8212; DroneBot Workshop\" src=\"https:\/\/dronebotworkshop.com\/embed\/#?secret=xvbPMfcDOz#?secret=NkQQeQAbCA\" data-secret=\"NkQQeQAbCA\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n\/\/ Define Motor Connections\r\n\/\/ Right Front Motor\r\n#define MF_PWMA 19\r\n#define MF_AI1 32\r\n#define MF_AI2 23\r\n\r\n\/\/ Left Front Motor\r\n#define MF_PWMB 26\r\n#define MF_BI1 33\r\n#define MF_BI2 25\r\n\r\n\/\/ Right Rear Motor\r\n#define MR_PWMA 27\r\n#define MR_AI1 12\r\n#define MR_AI2 14\r\n\r\n\/\/ Left Rear Motor\r\n#define MR_PWMB 4\r\n#define MR_BI1 13\r\n#define MR_BI2 2\r\n\r\n\/\/ Define some preset motor speeds (0 - 255, adjust as desired)\r\nint speed_slow = 100;\r\nint speed_fast = 250;\r\n\r\nvoid setup() {\r\n\r\n  \/\/ Set all connections as outputs\r\n  pinMode(MF_PWMA, OUTPUT);\r\n  pinMode(MF_AI1, OUTPUT);\r\n  pinMode(MF_AI2, OUTPUT);\r\n  pinMode(MF_PWMB, OUTPUT);\r\n  pinMode(MF_BI1, OUTPUT);\r\n  pinMode(MF_BI2, OUTPUT);\r\n  pinMode(MR_PWMA, OUTPUT);\r\n  pinMode(MR_AI1, OUTPUT);\r\n  pinMode(MR_AI2, OUTPUT);\r\n  pinMode(MR_PWMB, OUTPUT);\r\n  pinMode(MR_BI1, OUTPUT);\r\n  pinMode(MR_BI2, OUTPUT);\r\n}\r\n\r\nvoid loop() {\r\n\r\n  \/\/ Front Right Motor  *****************************************************************\r\n\r\n  \/\/ FR - Forward Slow Speed\r\n  digitalWrite(MF_AI1, HIGH);\r\n  digitalWrite(MF_AI2, LOW);\r\n  analogWrite(MF_PWMA, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ FR - Forward Fast Speed\r\n  analogWrite(MF_PWMA, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ FR - Stop 1 second\r\n  analogWrite(MF_PWMA, 0);\r\n  delay(1000);\r\n\r\n  \/\/ FR - Reverse Fast Speed\r\n  digitalWrite(MF_AI1, LOW);\r\n  digitalWrite(MF_AI2, HIGH);\r\n  analogWrite(MF_PWMA, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ FR - Reverse Slow Speed\r\n  analogWrite(MF_PWMA, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ FR - Stop 1 second\r\n  analogWrite(MF_PWMA, 0);\r\n  delay(1000);\r\n\r\n  \/\/ Front Left Motor  *****************************************************************\r\n\r\n  \/\/ FL - Forward Slow Speed\r\n  digitalWrite(MF_BI1, HIGH);\r\n  digitalWrite(MF_BI2, LOW);\r\n  analogWrite(MF_PWMB, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ FL - Forward Fast Speed\r\n  analogWrite(MF_PWMB, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ FL - Stop 1 second\r\n  analogWrite(MF_PWMB, 0);\r\n  delay(1000);\r\n\r\n  \/\/ FL - Reverse Fast Speed\r\n  digitalWrite(MF_BI1, LOW);\r\n  digitalWrite(MF_BI2, HIGH);\r\n  analogWrite(MF_PWMB, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ FL - Reverse Slow Speed\r\n  analogWrite(MF_PWMB, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ FL - Stop 1 second\r\n  analogWrite(MF_PWMB, 0);\r\n  delay(1000);\r\n\r\n  \/\/ Rear Right Motor  *****************************************************************\r\n\r\n  \/\/ RR - Forward Slow Speed\r\n  digitalWrite(MR_AI1, HIGH);\r\n  digitalWrite(MR_AI2, LOW);\r\n  analogWrite(MR_PWMA, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ RR - Forward Fast Speed\r\n  analogWrite(MR_PWMA, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ RR - Stop 1 second\r\n  analogWrite(MR_PWMA, 0);\r\n  delay(1000);\r\n\r\n  \/\/ RR - Reverse Fast Speed\r\n  digitalWrite(MR_AI1, LOW);\r\n  digitalWrite(MR_AI2, HIGH);\r\n  analogWrite(MR_PWMA, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ RR - Reverse Slow Speed\r\n  analogWrite(MR_PWMA, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ RR - Stop 1 second\r\n  analogWrite(MR_PWMA, 0);\r\n  delay(1000);\r\n\r\n  \/\/ Rear Left Motor  *****************************************************************\r\n\r\n  \/\/ RL - Forward Slow Speed\r\n  digitalWrite(MR_BI1, HIGH);\r\n  digitalWrite(MR_BI2, LOW);\r\n  analogWrite(MR_PWMB, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ RL - Forward Fast Speed\r\n  analogWrite(MR_PWMB, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ RL - Stop 1 second\r\n  analogWrite(MR_PWMB, 0);\r\n  delay(1000);\r\n\r\n  \/\/ RL - Reverse Fast Speed\r\n  digitalWrite(MR_BI1, LOW);\r\n  digitalWrite(MR_BI2, HIGH);\r\n  analogWrite(MR_PWMB, speed_fast);\r\n  delay(2000);\r\n\r\n  \/\/ RL - Reverse Slow Speed\r\n  analogWrite(MR_PWMB, speed_slow);\r\n  delay(2000);\r\n\r\n  \/\/ RL - Stop 1 second\r\n  analogWrite(MR_PWMB, 0);\r\n  delay(1000);\r\n}<\/pre>\n<p><span style=\"font-weight: 400;\">Our motors are driven using PWM (Pulse Width Modulation), so this sketch uses the simple <\/span><i><span style=\"font-weight: 400;\">analogWrite <\/span><\/i><span style=\"font-weight: 400;\">command that most Arduino users are familiar with. It works, but with the ESP32, there are better ways of generating PWM for motors.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This is a pretty basic sketch, we simply set the control inputs to the motor driver to set direction and apply a PWM signal to the PWM input.\u00a0 We deal with each motor in sequence, moving it, stopping it, and then reversing it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Load it up to your ESP32 and watch it work. It\u2019s a good way to determine if everything is hooked up correctly.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Functions for Controlling Motors\u00a0<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">As we have already seen, Mecanum wheels can move a vehicle in any direction by manipulating the direction of each wheel.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">With the TB6612FNG motor driver, you change the motor rotation direction by changing the state of the input signals. These are labeled AI1 and AI2 for channel A and BI1 and BI2 for channel B. The truth table for the motor inputs is shown below:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9187\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-motors.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-motors.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-motors.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Since we require two bits per motor for discretion control and since we have four motors, this means that a total of eight bits is required to specify every possible motor direction movement. And, of course, eight bits is a byte!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This means that each of the Mecanum \u201cmodes\u201d can be specified with a single byte. Let\u2019s go over them:<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Straight Modes<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9185\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-straight.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-straight.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-straight.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">There are two straight modes, one forward and one backward.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Sideways Modes<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9184\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-sideways.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-sideways.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-sideways.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">There are also two sideways modes, one to the right and one to the left.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Diagonal Modes<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9180\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-diagonal.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-diagonal.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-diagonal.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">There are four diagonal modes, as indicated in the above diagram. Note that the vehicle is not confined to these four directions; these are just the directions it would travel if the wheels were all moving at the same speed. By varying the speed between the active wheels, you can move the car in any direction.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Pivot Modes<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9182\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">And there are also four pivot modes, as shown here.<\/span><\/p>\n<h4>Pivot Sideways<\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9181\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot-sideways.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot-sideways.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-pivot-sideways.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p>We can also pivot sideways as well.<\/p>\n<h4><span style=\"font-weight: 400;\">Rotate Mode<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9183\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-rotate.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-rotate.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-rotate.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Finally, we have two rotation modes, one clockwise and one counterclockwise.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Mode Summary<\/span><\/h4>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9186\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-summary.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-summary.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-functions-summary.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">The above chart summarizes all the modes, as well as the corresponding byte pattern required to execute them.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Mecanum Functions Test<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Now that we have determined that we can direct our Mecanum Motors using a single byte, we can create a sketch to test it out.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We will also use a different method of producing and controlling PWM signals for our motors.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">ESP32 PWM<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">Although the<\/span><i><span style=\"font-weight: 400;\"> analogWrite<\/span><\/i><span style=\"font-weight: 400;\"> command works with the ESP32, it is not the preferred method of creating PWM with this microcontroller.\u00a0 It does give you control over the pulse width, but to modify the base frequency, you need to modify a few registers.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The ESP32 has two other methods of PWM control:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Motor Control Pulse Width Modulator (MCPWM)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">LED PWM Controller (LEDC)<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">At first glance, it would appear that the MCPWM method would be the most suitable; after all, it is literally called \u201cMotor Control Pulse Width Modulator\u201d! However, there are only two MCPWM channels in an ESP32, and we need four. In addition, it is somewhat difficult to code for this method using the Arduino IDE.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In contrast, there are 16 LEDC channels in the ESP32, which can easily be used to control motors. Don\u2019t let the \u201cLED\u201d in the name dissuade you!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One thing about those 16 channels that you need to be aware of is that the frequency that they operate at is controlled by two registers, with each register controlling eight channels. So you can only have two different frequencies. In our application, this is irrelevant, as we want all of our channels operating at the same frequency.\u00a0<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Mecanum Functions Test Sketch<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">Here is a sketch to test the Mecanum Wheels in several different \u201cmodes.\u201d I wrote it to use both the sideways and straight modes, but you can expand upon it to use the other ones if you wish.<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"mecanum-test.ino\">\/*\r\n  4WD Mecanum Wheel Robot Car Base - Simple Maneuver Test\r\n  mecanum-test.ino\r\n  Cycles 4WD Mecanum Wheel Robot Car through simple manuuvers\r\n  Uses ESP32 DevKitC (other ESP32 boards will work)\r\n  Uses 2 TB6612FNG Motor Drivers, also compatible with L298N\r\n  \r\n  DroneBot Workshop 2022\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"NkQQeQAbCA\"><a href=\"https:\/\/dronebotworkshop.com\/\">Welcome to the Workshop!<\/a><\/blockquote><iframe class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" title=\"&#8220;Welcome to the Workshop!&#8221; &#8212; DroneBot Workshop\" src=\"https:\/\/dronebotworkshop.com\/embed\/#?secret=xvbPMfcDOz#?secret=NkQQeQAbCA\" data-secret=\"NkQQeQAbCA\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n\/\/ Define Motor Connections\r\n\/\/ Right Front Motor\r\n#define MF_PWMA 19\r\n#define MF_AI1 32\r\n#define MF_AI2 23\r\n\r\n\/\/ Left Front Motor\r\n#define MF_PWMB 26\r\n#define MF_BI1 33\r\n#define MF_BI2 25\r\n\r\n\/\/ Right Rear Motor\r\n#define MR_PWMA 27\r\n#define MR_AI1 12\r\n#define MR_AI2 14\r\n\r\n\/\/ Left Rear Motor\r\n#define MR_PWMB 4\r\n#define MR_BI1 13\r\n#define MR_BI2 2\r\n\r\n\/\/ Define PWM Motor Speed Variables\r\nint rf_PWM = 0;  \/\/ Right Front Motor\r\nint lf_PWM = 0;  \/\/ Left Front Motor\r\nint rr_PWM = 0;  \/\/ Right Rear Motor\r\nint lr_PWM = 0;  \/\/ Left Front Motor\r\n\r\n\/\/ Define Bytes to represent Mecannum Wheel Modes\r\n\/\/ Individual bits define TB6612FNG motor driver module input states\r\n\/\/ B7 = MF_AI1, B6 = MF_AI2, B5 = MF_BI1, B4 = MF_BI2, B3 = MR_AI1, B2 = MR_AI2, B1 = MR_BI1, B0 = MR_BI2\r\n\r\nconst byte MEC_STRAIGHT_FORWARD = B10101010;\r\nconst byte MEC_STRAIGHT_BACKWARD = B01010101;\r\nconst byte MEC_SIDEWAYS_RIGHT = B01101001;\r\nconst byte MEC_SIDEWAYS_LEFT = B10010110;\r\nconst byte MEC_DIAGONAL_45 = B00101000;\r\nconst byte MEC_DIAGONAL_135 = B10000010;\r\nconst byte MEC_DIAGONAL_225 = B00010100;\r\nconst byte MEC_DIAGONAL_315 = B01000001;\r\nconst byte MEC_PIVOT_RIGHT_FORWARD = B00100010;\r\nconst byte MEC_PIVOT_RIGHT_BACKWARD = B00010001;\r\nconst byte MEC_PIVOT_LEFT_FORWARD = B10001000;\r\nconst byte MEC_PIVOT_LEFT_BACKWARD = B01000100;\r\nconst byte MEC_ROTATE_CLOCKWISE = B01100110;\r\nconst byte MEC_ROTATE_COUNTERCLOCKWISE = B10011001;\r\nconst byte MEC_PIVOT_SIDEWAYS_FRONT_RIGHT = B01100000;\r\nconst byte MEC_PIVOT_SIDEWAYS_FRONT_LEFT = B10010000;\r\nconst byte MEC_PIVOT_SIDEWAYS_REAR_RIGHT = B00001001;\r\nconst byte MEC_PIVOT_SIDEWAYS_REAR_LEFT = B00000110;\r\n\r\n\/\/ Variable for test time delay\r\nint timeDelay = 1000;\r\n\r\n\/\/ PWM Parameters for motor control\r\n\/\/ PWM Frequency = 1KHz\r\nconst int mtrPWMFreq = 1000;\r\n\/\/ PWM Resolution\r\nconst int mtrPWMResolution = 8;\r\n\/\/ Define PWM channels for each motor\r\nconst int mtrRFpwmchannel = 4;\r\nconst int mtrLFpwmchannel = 5;\r\nconst int mtrRRpwmchannel = 6;\r\nconst int mtrLRpwmchannel = 7;\r\n\r\nvoid moveMotors(int speedRF, int speedLF, int speedRR, int speedLR, byte dircontrol) {\r\n\r\n  \/\/ Moves all 4 motors\r\n  \/\/ Directions specified in direction byte\r\n\r\n  \/\/ Right Front Motor\r\n  digitalWrite(MF_AI1, bitRead(dircontrol, 7));\r\n  digitalWrite(MF_AI2, bitRead(dircontrol, 6));\r\n  ledcWrite(mtrRFpwmchannel, abs(speedRF));\r\n\r\n  \/\/ Left Front Motor\r\n  digitalWrite(MF_BI1, bitRead(dircontrol, 5));\r\n  digitalWrite(MF_BI2, bitRead(dircontrol, 4));\r\n  ledcWrite(mtrLFpwmchannel, abs(speedLF));\r\n\r\n  \/\/ Right Rear Motor\r\n  digitalWrite(MR_AI1, bitRead(dircontrol, 3));\r\n  digitalWrite(MR_AI2, bitRead(dircontrol, 2));\r\n  ledcWrite(mtrRRpwmchannel, abs(speedRR));\r\n\r\n  \/\/ Left Rear Motor\r\n  digitalWrite(MR_BI1, bitRead(dircontrol, 1));\r\n  digitalWrite(MR_BI2, bitRead(dircontrol, 0));\r\n  ledcWrite(mtrLRpwmchannel, abs(speedLR));\r\n}\r\n\r\nvoid stopMotors() {\r\n\r\n  \/\/ Stops all motors and motor controllers\r\n  ledcWrite(mtrRFpwmchannel, 0);\r\n  ledcWrite(mtrLFpwmchannel, 0);\r\n  ledcWrite(mtrRRpwmchannel, 0);\r\n  ledcWrite(mtrLRpwmchannel, 0);\r\n\r\n  digitalWrite(MF_AI1, 0);\r\n  digitalWrite(MF_AI2, 0);\r\n  digitalWrite(MF_BI1, 0);\r\n  digitalWrite(MF_BI2, 0);\r\n  digitalWrite(MR_AI1, 0);\r\n  digitalWrite(MR_AI2, 0);\r\n  digitalWrite(MR_BI1, 0);\r\n  digitalWrite(MR_BI2, 0);\r\n}\r\n\r\nvoid setup() {\r\n\r\n  \/\/ Set up Serial Monitor\r\n  Serial.begin(9600);\r\n\r\n  \/\/ Set all connections as outputs\r\n  pinMode(MF_PWMA, OUTPUT);\r\n  pinMode(MF_AI1, OUTPUT);\r\n  pinMode(MF_AI2, OUTPUT);\r\n  pinMode(MF_PWMB, OUTPUT);\r\n  pinMode(MF_BI1, OUTPUT);\r\n  pinMode(MF_BI2, OUTPUT);\r\n  pinMode(MR_PWMA, OUTPUT);\r\n  pinMode(MR_AI1, OUTPUT);\r\n  pinMode(MR_AI2, OUTPUT);\r\n  pinMode(MR_PWMB, OUTPUT);\r\n  pinMode(MR_BI1, OUTPUT);\r\n  pinMode(MR_BI2, OUTPUT);\r\n\r\n  \/\/Set up PWM channels with frequency and resolution\r\n  ledcSetup(mtrRFpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrLFpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrRRpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrLRpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n\r\n  \/\/ Attach channels to PWM output pins\r\n  ledcAttachPin(MF_PWMA, mtrRFpwmchannel);\r\n  ledcAttachPin(MF_PWMB, mtrLFpwmchannel);\r\n  ledcAttachPin(MR_PWMA, mtrRRpwmchannel);\r\n  ledcAttachPin(MR_PWMB, mtrLRpwmchannel);\r\n\r\n  \/\/ Test speed for all motors (change as desired)\r\n  rf_PWM = 200;  \/\/ Right Front Motor\r\n  lf_PWM = 200;  \/\/ Left Front Motor\r\n  rr_PWM = 200;  \/\/ Right Rear Motor\r\n  lr_PWM = 200;  \/\/ Left Front Motor\r\n}\r\n\r\nvoid loop() {\r\n\r\n  \/\/ Cycle through some Mecanum Wheel modes\r\n\r\n  delay(3000);  \r\n\r\n  \/\/ Straight Forward\r\n  Serial.println(\"Straight Forward\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_STRAIGHT_FORWARD);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  delay(500);\r\n\r\n  \/\/ Straight Backward\r\n  Serial.println(\"Straight Backward\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_STRAIGHT_BACKWARD);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  delay(500);\r\n\r\n  \/\/ Sideways Right\r\n  Serial.println(\"Sideways Right\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_SIDEWAYS_RIGHT);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  delay(500);\r\n\r\n  \/\/ Sideways Left\r\n  Serial.println(\"Sideways Left\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_SIDEWAYS_LEFT);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 45 Degrees\r\n  Serial.println(\"Diagonal 45 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_45);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 225 Degrees\r\n  Serial.println(\"Diagonal 225 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_225);\r\n  delay(timeDelay);\r\n  moveMotors(0, 0, 0, 0, MEC_DIAGONAL_225);\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 135 Degrees\r\n  Serial.println(\"Diagonal 135 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_135);\r\n  delay(timeDelay);\r\n  moveMotors(0, 0, 0, 0, MEC_DIAGONAL_135);\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 315 Degrees\r\n  Serial.println(\"Diagonal 315 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_315);\r\n  delay(timeDelay);\r\n  moveMotors(0, 0, 0, 0, MEC_STRAIGHT_FORWARD);\r\n  delay(500);\r\n}<\/pre>\n<p><span style=\"font-weight: 400;\">You\u2019ll note that each of the \u201cMecanum Modes\u201d has been defined as a byte. This byte is passed to the <\/span><i><span style=\"font-weight: 400;\">moveMotors<\/span><\/i><span style=\"font-weight: 400;\"> function, which accepts it, as well as the speed values for the four motors.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Note the statements in the Setup function that prepare the LEDC registers. In this example, we use a frequency of 1Khz, defined by the constant <\/span><i><span style=\"font-weight: 400;\">mtrPWMFreq<\/span><\/i><span style=\"font-weight: 400;\">, and a PWM resolution of 8-bits (0-255) as defined in the constant <\/span><i><span style=\"font-weight: 400;\">mtrPWMResolution<\/span><\/i><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In the Loop, we exercise the motors in several different modes.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Load it up and try it out. If you can, put the car on the floor and watch it move. In a perfect world, it will end up exactly where it started, but it is more likely to end up <\/span><span style=\"font-weight: 400;\">near <\/span><span style=\"font-weight: 400;\">where it started. A lot depends upon the floor surface.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Neopixels<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Another key component in our car is the NeoPixels we use as indicators. There are five of these, one for each motor and a fifth Status LED.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We have used NeoPixels in several projects already, and I covered their operation in detail in the article \u201c<a href=\"https:\/\/dronebotworkshop.com\/rgb-leds\/\" target=\"_blank\" rel=\"noopener\">RGB LEDs \u2013 Colorful Arduino Experiments<\/a>\u201d. You may want to check that out if you are unfamiliar with how they operate.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The NeoPixels I\u2019m using are <\/span><a href=\"https:\/\/www.adafruit.com\/product\/1734\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">8mm individual NeoPixels from Adafruit<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Neopixels Hookup\u00a0<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">NeoPixels are serial devices, and they each have four leads:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9201\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/Adafruit-neopixel-led.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/Adafruit-neopixel-led.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/Adafruit-neopixel-led.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The Data In. This is a 5-volt logic signal.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">5V &#8211; NeoPixels are powered by 5 volts.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Ground<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Data Out &#8211; This is the output, which will be connected to the next NeoPixel in the string.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">It\u2019s also a good idea to put a small capacitor across the 5V and GND leads on each NeoPixel. This capacitor should be as physically close to the LED as possible.\u00a0 Adafruit recommends a value of 0.1uf (100nf).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As we require 5-volt logic for our NeoPixels, I\u2019m using a logic-level converter to handle the conversion. You could also use a transistor, but I have a drawer full of these!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Here is the hookup of our five NeoPixels. Note that this schematic is in addition to the motor driver hookup; I just removed those connections for clarity.<\/span><\/p>\n<figure id=\"attachment_9197\" aria-describedby=\"caption-attachment-9197\" style=\"width: 768px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/03\/NeoPixel-LED-Hookup-Large.jpg?ssl=1\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9197 size-full\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/neopixel-led-hookup.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/neopixel-led-hookup.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/neopixel-led-hookup.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-9197\" class=\"wp-caption-text\">Click on the wiring diagram to open a larger image<\/figcaption><\/figure>\n<h3><span style=\"font-weight: 400;\">LED Test Script<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">To test the LEDs, we will use the Adafruit NeoPixel Library, which makes sense as we are using Adafruit NeoPixels. If you don\u2019t have this library, you may use your Library Manager to install it.<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"mecanum-led-test.ino\">\/*\r\n  4WD Mecanum Wheel Robot Car Base - Simple Maneuver Test with status LEDs\r\n  mecanum-led-test.ino\r\n  Cycles 4WD Mecanum Wheel Robot Car through simple manuuvers\r\n  Uses ESP32 DevKitC (other ESP32 boards will work)\r\n  Uses 2 TB6612FNG Motor Drivers, also compatible with L298N\r\n  Requires Adafruit NeoPixel Library (and dependant libraries)\r\n  Updated for 5 LEDs \r\n  \r\n  DroneBot Workshop 2022\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"NkQQeQAbCA\"><a href=\"https:\/\/dronebotworkshop.com\/\">Welcome to the Workshop!<\/a><\/blockquote><iframe class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" title=\"&#8220;Welcome to the Workshop!&#8221; &#8212; DroneBot Workshop\" src=\"https:\/\/dronebotworkshop.com\/embed\/#?secret=xvbPMfcDOz#?secret=NkQQeQAbCA\" data-secret=\"NkQQeQAbCA\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n\/\/Include NeoPixel library\r\n#include &lt;Adafruit_NeoPixel.h&gt;\r\n\r\n\/\/ Define Motor Connections\r\n\/\/ Right Front Motor\r\n#define MF_PWMA 19\r\n#define MF_AI1 32\r\n#define MF_AI2 23\r\n\r\n\/\/ Left Front Motor\r\n#define MF_PWMB 26\r\n#define MF_BI1 33\r\n#define MF_BI2 25\r\n\r\n\/\/ Right Rear Motor\r\n#define MR_PWMA 27\r\n#define MR_AI1 12\r\n#define MR_AI2 14\r\n\r\n\/\/ Left Rear Motor\r\n#define MR_PWMB 4\r\n#define MR_BI1 13\r\n#define MR_BI2 2\r\n\r\n\/\/ Define PWM Motor Speed Variables\r\nint rf_PWM = 0;  \/\/ Right Front Motor\r\nint lf_PWM = 0;  \/\/ Left Front Motor\r\nint rr_PWM = 0;  \/\/ Right Rear Motor\r\nint lr_PWM = 0;  \/\/ Left Front Motor\r\n\r\n\/\/ Define Bytes to represent Mecannum Wheel Modes\r\n\/\/ Individual bits define TB6612FNG motor driver module input states\r\n\/\/ B7 = MF_AI1, B6 = MF_AI2, B5 = MF_BI1, B4 = MF_BI2, B3 = MR_AI1, B2 = MR_AI2, B1 = MR_BI1, B0 = MR_BI2\r\n\r\nconst byte MEC_STRAIGHT_FORWARD = B10101010;\r\nconst byte MEC_STRAIGHT_BACKWARD = B01010101;\r\nconst byte MEC_SIDEWAYS_RIGHT = B01101001;\r\nconst byte MEC_SIDEWAYS_LEFT = B10010110;\r\nconst byte MEC_DIAGONAL_45 = B00101000;\r\nconst byte MEC_DIAGONAL_135 = B10000010;\r\nconst byte MEC_DIAGONAL_225 = B00010100;\r\nconst byte MEC_DIAGONAL_315 = B01000001;\r\nconst byte MEC_PIVOT_RIGHT_FORWARD = B00100010;\r\nconst byte MEC_PIVOT_RIGHT_BACKWARD = B00010001;\r\nconst byte MEC_PIVOT_LEFT_FORWARD = B10001000;\r\nconst byte MEC_PIVOT_LEFT_BACKWARD = B01000100;\r\nconst byte MEC_ROTATE_CLOCKWISE = B01100110;\r\nconst byte MEC_ROTATE_COUNTERCLOCKWISE = B10011001;\r\nconst byte MEC_PIVOT_SIDEWAYS_FRONT_RIGHT = B01100000;\r\nconst byte MEC_PIVOT_SIDEWAYS_FRONT_LEFT = B10010000;\r\nconst byte MEC_PIVOT_SIDEWAYS_REAR_RIGHT = B00001001;\r\nconst byte MEC_PIVOT_SIDEWAYS_REAR_LEFT = B00000110;\r\n\r\n\/\/ Variable for test time delay\r\nint timeDelay = 1000;\r\n\r\n\/\/ PWM Parameters for motor control\r\n\/\/ PWM Frequency = 1KHz\r\nconst int mtrPWMFreq = 1000;\r\n\/\/ PWM Resolution\r\nconst int mtrPWMResolution = 8;\r\n\/\/ Define PWM channels for each motor\r\nconst int mtrRFpwmchannel = 4;\r\nconst int mtrLFpwmchannel = 5;\r\nconst int mtrRRpwmchannel = 6;\r\nconst int mtrLRpwmchannel = 7;\r\n\r\n\/\/ NeoPixel string output pin\r\n#define NEOPIX_PORT 5\r\n\r\n\/\/ Number of NeoPixels in string\r\n#define NUMPIXELS 5\r\n\r\n\/\/ Name each LED for easier reference\r\n#define NEO_STATUS 0\r\n#define NEO_RF 1\r\n#define NEO_LF 2\r\n#define NEO_RR 3\r\n#define NEO_LR 4\r\n\r\n\/\/LED Color Definitions\r\n#define LED_RED 255, 0, 0\r\n#define LED_GREEN 0, 255, 0\r\n#define LED_BLUE 0, 0, 255\r\n#define LED_YELLOW 255, 255, 0\r\n\r\n\/\/ Create \"pixels\" object representing NeoPixel string\r\nAdafruit_NeoPixel pixels(NUMPIXELS, NEOPIX_PORT, NEO_RGB + NEO_KHZ800);\r\n\r\nvoid moveMotors(int speedRF, int speedLF, int speedRR, int speedLR, byte dircontrol) {\r\n\r\n  \/\/ Moves all 4 motors\r\n  \/\/ Directions specified in direction byte\r\n\r\n  \/\/ Right Front Motor\r\n  digitalWrite(MF_AI1, bitRead(dircontrol, 7));\r\n  digitalWrite(MF_AI2, bitRead(dircontrol, 6));\r\n  ledcWrite(mtrRFpwmchannel, abs(speedRF));\r\n\r\n  \/\/ Left Front Motor\r\n  digitalWrite(MF_BI1, bitRead(dircontrol, 5));\r\n  digitalWrite(MF_BI2, bitRead(dircontrol, 4));\r\n  ledcWrite(mtrLFpwmchannel, abs(speedLF));\r\n\r\n  \/\/ Right Rear Motor\r\n  digitalWrite(MR_AI1, bitRead(dircontrol, 3));\r\n  digitalWrite(MR_AI2, bitRead(dircontrol, 2));\r\n  ledcWrite(mtrRRpwmchannel, abs(speedRR));\r\n\r\n  \/\/ Left Rear Motor\r\n  digitalWrite(MR_BI1, bitRead(dircontrol, 1));\r\n  digitalWrite(MR_BI2, bitRead(dircontrol, 0));\r\n  ledcWrite(mtrLRpwmchannel, abs(speedLR));\r\n}\r\n\r\nvoid stopMotors() {\r\n\r\n  \/\/ Stops all motors and motor controllers\r\n  ledcWrite(mtrRFpwmchannel, 0);\r\n  ledcWrite(mtrLFpwmchannel, 0);\r\n  ledcWrite(mtrRRpwmchannel, 0);\r\n  ledcWrite(mtrLRpwmchannel, 0);\r\n\r\n  digitalWrite(MF_AI1, 0);\r\n  digitalWrite(MF_AI2, 0);\r\n  digitalWrite(MF_BI1, 0);\r\n  digitalWrite(MF_BI2, 0);\r\n  digitalWrite(MR_AI1, 0);\r\n  digitalWrite(MR_AI2, 0);\r\n  digitalWrite(MR_BI1, 0);\r\n  digitalWrite(MR_BI2, 0);\r\n}\r\n\r\nvoid ledMotorStatus(byte dircontrol) {\r\n\r\n  \/\/ Sets status LEDs to indicate motor direction\r\n\r\n  \/\/ Right front\r\n  if ((bitRead(dircontrol, 7) == 1) &amp;&amp; (bitRead(dircontrol, 6) == 0)) {\r\n    \/\/ Motor moves forward\r\n    \/\/ Turn Right Front NeoPixel BLUE\r\n    pixels.setPixelColor(NEO_RF, pixels.Color(LED_BLUE));\r\n  } else if ((bitRead(dircontrol, 7) == 0) &amp;&amp; (bitRead(dircontrol, 6) == 1)) {\r\n    \/\/ Motor moves in reverse\r\n    \/\/ Turn Right Front NeoPixel YELLOW\r\n    pixels.setPixelColor(NEO_RF, pixels.Color(LED_YELLOW));\r\n  } else {\r\n    \/\/ Motor is stopped\r\n    \/\/ Turn Right Front NeoPixel RED\r\n    pixels.setPixelColor(NEO_RF, pixels.Color(LED_RED));\r\n  }\r\n\r\n  \/\/ Left front\r\n  if ((bitRead(dircontrol, 5) == 1) &amp;&amp; (bitRead(dircontrol, 4) == 0)) {\r\n    \/\/ Motor moves forward\r\n    \/\/ Turn Left Front NeoPixel BLUE\r\n    pixels.setPixelColor(NEO_LF, pixels.Color(LED_BLUE));\r\n  } else if ((bitRead(dircontrol, 5) == 0) &amp;&amp; (bitRead(dircontrol, 4) == 1)) {\r\n    \/\/ Motor moves in reverse\r\n    \/\/ Turn Left Front NeoPixel YELLOW\r\n    pixels.setPixelColor(NEO_LF, pixels.Color(LED_YELLOW));\r\n  } else {\r\n    \/\/ Motor is stopped\r\n    \/\/ Turn left Front NeoPixel RED\r\n    pixels.setPixelColor(NEO_LF, pixels.Color(LED_RED));\r\n  }\r\n\r\n  \/\/ Right rear\r\n  if ((bitRead(dircontrol, 3) == 1) &amp;&amp; (bitRead(dircontrol, 2) == 0)) {\r\n    \/\/ Motor moves forward\r\n    \/\/ Turn Right Rear NeoPixel BLUE\r\n    pixels.setPixelColor(NEO_RR, pixels.Color(LED_BLUE));\r\n  } else if ((bitRead(dircontrol, 3) == 0) &amp;&amp; (bitRead(dircontrol, 2) == 1)) {\r\n    \/\/ Motor moves in reverse\r\n    \/\/ Turn Right Rear NeoPixel YELLOW\r\n    pixels.setPixelColor(NEO_RR, pixels.Color(LED_YELLOW));\r\n  } else {\r\n    \/\/ Motor is stopped\r\n    \/\/ Turn Right Rear NeoPixel RED\r\n    pixels.setPixelColor(NEO_RR, pixels.Color(LED_RED));\r\n  }\r\n\r\n  \/\/ Left rear\r\n  if ((bitRead(dircontrol, 1) == 1) &amp;&amp; (bitRead(dircontrol, 0) == 0)) {\r\n    \/\/ Motor moves forward\r\n    \/\/ Turn Left Rear NeoPixel BLUE\r\n    pixels.setPixelColor(NEO_LR, pixels.Color(LED_BLUE));\r\n  } else if ((bitRead(dircontrol, 1) == 0) &amp;&amp; (bitRead(dircontrol, 0) == 1)) {\r\n    \/\/ Motor moves in reverse\r\n    \/\/ Turn Left Rear NeoPixel YELLOW\r\n    pixels.setPixelColor(NEO_LR, pixels.Color(LED_YELLOW));\r\n  } else {\r\n    \/\/ Motor is stopped\r\n    \/\/ Turn Left Rear NeoPixel RED\r\n    pixels.setPixelColor(NEO_LR, pixels.Color(LED_RED));\r\n  }\r\n\r\n  \/\/ Update\r\n  pixels.show();\r\n}\r\n\r\nvoid ledTurnOff() {\r\n  \/\/ Turn off all NeoPixels\r\n  pixels.clear();\r\n  pixels.show();\r\n}\r\n\r\nvoid ledAllStop() {\r\n  \/\/ Turn all NeoPixels RED\r\n  pixels.clear();\r\n  pixels.setPixelColor(NEO_STATUS, pixels.Color(LED_RED));\r\n  pixels.setPixelColor(NEO_RF, pixels.Color(LED_RED));\r\n  pixels.setPixelColor(NEO_LF, pixels.Color(LED_RED));\r\n  pixels.setPixelColor(NEO_RR, pixels.Color(LED_RED));\r\n  pixels.setPixelColor(NEO_LR, pixels.Color(LED_RED));\r\n  pixels.show();\r\n}\r\n\r\nvoid setup() {\r\n\r\n  \/\/ Set up Serial Monitor\r\n  Serial.begin(9600);\r\n\r\n  \/\/ Set all connections as outputs\r\n  pinMode(MF_PWMA, OUTPUT);\r\n  pinMode(MF_AI1, OUTPUT);\r\n  pinMode(MF_AI2, OUTPUT);\r\n  pinMode(MF_PWMB, OUTPUT);\r\n  pinMode(MF_BI1, OUTPUT);\r\n  pinMode(MF_BI2, OUTPUT);\r\n  pinMode(MR_PWMA, OUTPUT);\r\n  pinMode(MR_AI1, OUTPUT);\r\n  pinMode(MR_AI2, OUTPUT);\r\n  pinMode(MR_PWMB, OUTPUT);\r\n  pinMode(MR_BI1, OUTPUT);\r\n  pinMode(MR_BI2, OUTPUT);\r\n\r\n  \/\/Set up PWM channels with frequency and resolution\r\n  ledcSetup(mtrRFpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrLFpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrRRpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n  ledcSetup(mtrLRpwmchannel, mtrPWMFreq, mtrPWMResolution);\r\n\r\n  \/\/ Attach channels to PWM output pins\r\n  ledcAttachPin(MF_PWMA, mtrRFpwmchannel);\r\n  ledcAttachPin(MF_PWMB, mtrLFpwmchannel);\r\n  ledcAttachPin(MR_PWMA, mtrRRpwmchannel);\r\n  ledcAttachPin(MR_PWMB, mtrLRpwmchannel);\r\n\r\n  \/\/ Test speed for all motors (change as desired)\r\n  rf_PWM = 200;  \/\/ Right Front Motor\r\n  lf_PWM = 200;  \/\/ Left Front Motor\r\n  rr_PWM = 200;  \/\/ Right Rear Motor\r\n  lr_PWM = 200;  \/\/ Left Front Motor\r\n\r\n  \/\/ Initialize NeoPixels\r\n  pixels.begin();\r\n}\r\n\r\nvoid loop() {\r\n\r\n  \/\/ Cycle through some Mecanum Wheel modes\r\n  \/\/ Make sure we are stopped  \r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(3000);\r\n\r\n  \/\/ Straight Forward\r\n  Serial.println(\"Straight Forward\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_STRAIGHT_FORWARD);\r\n  ledMotorStatus(MEC_STRAIGHT_FORWARD);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Straight Backward\r\n  Serial.println(\"Straight Backward\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_STRAIGHT_BACKWARD);\r\n  ledMotorStatus(MEC_STRAIGHT_BACKWARD);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Sideways Right\r\n  Serial.println(\"Sideways Right\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_SIDEWAYS_RIGHT);\r\n  ledMotorStatus(MEC_SIDEWAYS_RIGHT);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Sideways Left\r\n  Serial.println(\"Sideways Left\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_SIDEWAYS_LEFT);\r\n  ledMotorStatus(MEC_SIDEWAYS_LEFT);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 45 Degrees\r\n  Serial.println(\"Diagonal 45 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_45);\r\n  ledMotorStatus(MEC_DIAGONAL_45);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 225 Degrees\r\n  Serial.println(\"Diagonal 225 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_225);\r\n  ledMotorStatus(MEC_DIAGONAL_225);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 135 Degrees\r\n  Serial.println(\"Diagonal 135 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_135);\r\n  ledMotorStatus(MEC_DIAGONAL_135);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n\r\n  \/\/ Diagonal 315 Degrees\r\n  Serial.println(\"Diagonal 315 Degrees\");\r\n  moveMotors(rf_PWM, lf_PWM, rr_PWM, lr_PWM, MEC_DIAGONAL_315);\r\n  ledMotorStatus(MEC_DIAGONAL_315);\r\n  delay(timeDelay);\r\n  stopMotors();\r\n  ledAllStop();\r\n  delay(500);\r\n}\r\n<\/pre>\n<p><span style=\"font-weight: 400;\">The script builds upon the last one, adding the NeoPixel functionality. The LEDs will change color depending on the motor direction:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Green for Forward<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Blue for Reverse<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Red for Stop<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">In this sketch, the Status LED will also illuminate when the motor is stopped.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Neopixel Library Concerns<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Unfortunately, after I put together the last sketch, I ran into an issue, the Adafruit NeoPixel Library conflicts with the ESP-NOW Library.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Rather than trying to resolve the conflict (which can be done), I decided to look for another NeoPixel library. And I found one, and as a bonus, it\u2019s a lot smaller and faster than its Adafruit counterpart.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The <\/span><a href=\"https:\/\/github.com\/Makuna\/NeoPixelBus\"><span style=\"font-weight: 400;\">NeoPixelBus Library by Michael C. Miller<\/span><\/a><span style=\"font-weight: 400;\"> is also available from your Library Manager. You\u2019ll want to install it in preparation for the final robot code.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Robot Construction<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">After all of our experimentation, it\u2019s finally time to build our Mecanum Wheel Robot Car!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Any base capable of holding four motors can be used for the car; in my case, I purchased a kit with the wheels and the base. You could also just buy the wheels and use them on an existing 4-wheel robot car base. Or you could be really creative and design your own.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">My Robot Build<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The base I used has two levels, which I like, as it has a lot of room for expansion.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The bottom level has the motors, as you expect it would, and it could be used alone without a top level (in fact, another model is available without the top level).\u00a0 The chassis has cutouts for speed sensors, and in the future, I might want to add them, so I left it empty.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The only other components mounted on the lower level are the four NeoPixel LEDs, which I mounted on small pieces of perfboard along with their respective 0.1uf filter capacitors.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Everything else is on the top layer. The main circuitry (i.e., the ESP32, motor drivers, and level converter) are mounted on a perfboard. The two 18650 batteries I used are also on the top so that I can easily remove them for recharging &#8211; sometime down the road I\u2019ll update the design to include a built-in charger, but not today.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I also included another small perfboard upon which I mounted a power switch and the Status NeoPixel. I used some brass standoffs to raise this to allow the wires from the motors and the front LEDs to run underneath.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Power Hookup\u00a0<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">As I just mentioned, I used a couple of 18650 batteries as a power source. These are used to power the motors directly and are also fed into a 5-volt regulator to supply 5 volts for the ESP32 and the NeoPixels.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9198\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/power-supply-hookup.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/power-supply-hookup.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/power-supply-hookup.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This is only one of several arrangements you can use to power up your project, there are many different ways of building the robot power supply:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Use a 6-volt battery pack (such as 4 AA calls) for the motors and a USB power bank for the 5-volt supply.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Use the same design I used, but replace the buck converter with a Low Dropout (LDO) regulator.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Bottom line &#8211; you need to supply your motors with their required voltage (and current), as well as 5 volts for the ESP32 and the NeoPixels.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Controller Construction<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Now we will switch our focus to the controller.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Our controller is constructed around a LilyGo TTGO T-Display module. This ESP32 module has an integrated TFT color display, two GPIO-connected pushbuttons, and a connection for a small LiPo battery that can be recharged from the module.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9178\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay1.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay1.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay1.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9179\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay2.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay2.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/lilygo-ttgo-tdisplay2.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">The only other component (besides a power switch for the battery) that we require is a standard analog joystick.\u00a0 These devices have two potentiometers (usually 5 or 10K) for the X and Y axis and a momentary contact pushbutton switch that is activated by pushing down on the joystick handle.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Joystick Functions\u00a0<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The joystick is connected to two of the analog inputs on the ESP32. An <\/span><i><span style=\"font-weight: 400;\">analogRead<\/span><\/i><span style=\"font-weight: 400;\"> can display each coordinated output in a range of 0 to 255 or 0 to 4095 if using the A\/D converter in 10-bit mode.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">However, for our purposes, it would be a lot better if we could get the readings on each coordinate to read from -255 to 255, with zero representing the center point, as follows:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9170\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-coordinates.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-coordinates.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-coordinates.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This arrangement will allow us to determine not only motor speed requirements but also which of the Mecanum modes we will need to send the car in the direction of the joystick.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The following illustrations show which mode is activated when the joystick is moved into different positions:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9171\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-01.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-01.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-01.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9172\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-02.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-02.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-02.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9173\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-03.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-03.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-03.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9174\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-04.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-04.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-04.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9175\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-05.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-05.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-05.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9176\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-06.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-06.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-06.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9177\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-07.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-07.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-07.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9202\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-08.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-08.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-08.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">\u00a0This chart summarizes the movements:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9203\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-summary.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-summary.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/joystick-functions-summary.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<h3><span style=\"font-weight: 400;\">Controller Hookup<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Since the LilyGo TTGO T-Display module already contains the display, pushbuttons, and battery charger, all that is required is to connect the joystick to the module.<\/span><\/p>\n<figure id=\"attachment_9168\" aria-describedby=\"caption-attachment-9168\" style=\"width: 768px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2023\/03\/TTGO-Remote-Hookup-Large.jpg?ssl=1\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9168 size-full\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/controller-hookup.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/controller-hookup.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/controller-hookup.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-9168\" class=\"wp-caption-text\">Click on the wiring diagram to open a larger image<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Note that some joysticks have the X and Y axis 90 degrees off of what you would expect, so you may need to reverse those leads.<\/span><\/p>\n<h3>TFT-eSPI Library Modifications<\/h3>\n<p>The sketch we will be writing for the controller will use the <a href=\"https:\/\/github.com\/Bodmer\/TFT_eSPI\" target=\"_blank\" rel=\"noopener\">TFT-eSPI Library by Bodmer<\/a>. You can install this library using the Library Manager in the Arduino IDE.\u00a0 You might have already installed it if you followed my instructions in the article about using<a href=\"https:\/\/dronebotworkshop.com\/gc9a01\/\" target=\"_blank\" rel=\"noopener\"> Round LCD Modules<\/a>, but you may need to update it, as it needs to be at least version 2.4.79 to work with the TTGO displays.<\/p>\n<p>After installing it, you will need to modify a file in the library to work with the TTGO T-Display.\u00a0 Here is how you do this:<\/p>\n<ol>\n<li>Navigate to the <em>TFT_eSPI<\/em> folder in your libraries folder (which usually lives under your Arduino folder).<\/li>\n<li>Look for <em>User_Setup_Select.h<\/em> and open it with a text editor.<\/li>\n<li>Comment out line 30, which reads <em>#include &lt;User_Setup.h&gt;<\/em><\/li>\n<li>Uncomment line 61, which reads<em> #include &lt;User_Setups\/Setup25_TTGO_T_Display.h&gt;<\/em><\/li>\n<li>Save the file.<\/li>\n<\/ol>\n<p>Once you do this, the library will work with the TTGO module.<\/p>\n<h3><span style=\"font-weight: 400;\">My Controller Build<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Putting together the controller was very simple.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I used the plastic case that the TTGO T-Display module was packaged in as my case. Of course, you could use another case, perhaps even a 3D-printed one.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">For a battery, I used a small 800ma LiPo, the type you would use for a small quadcopter. It fits very nicely inside the case.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I used a few nylon standoffs to raise the perfboard high enough to allow the battery leads to connect to the connector on the module.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">ESP32 Sketches<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Now that all the hardware is assembled, it is time to focus on the software.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Before we can create the scripts that we will need for both the car and its controller, we will need to get one very important piece of information from the ESP32s used in each device &#8211; the MAC Address.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">MAC Address Script<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The Media Access Control, or MAC, Address is a unique address assigned to every network device on the planet. Both ESP32 boards have their own MAC addresses.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The ESP-NOW protocol that we will use to communicate between the devices requires each unit&#8217;s MAC Address.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Here is a simple sketch to get the MAC address. You\u2019ll need to run it on both the car and the controller. Make sure to save the results!<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"getmac.ino\">\/*\r\n  Print ESP32 MAC Address\r\n  getmac.ino\r\n  Prints MAC address to serial monitor\r\n  Use to record address for use with ESP-NOW\r\n  \r\n  DroneBot Workshop 2022\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"NkQQeQAbCA\"><a href=\"https:\/\/dronebotworkshop.com\/\">Welcome to the Workshop!<\/a><\/blockquote><iframe class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" title=\"&#8220;Welcome to the Workshop!&#8221; &#8212; DroneBot Workshop\" src=\"https:\/\/dronebotworkshop.com\/embed\/#?secret=xvbPMfcDOz#?secret=NkQQeQAbCA\" data-secret=\"NkQQeQAbCA\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n#include \"WiFi.h\"\r\n \r\nvoid setup(){\r\n  Serial.begin(115200);\r\n \r\n  WiFi.mode(WIFI_MODE_STA);\r\n \r\n  Serial.println(WiFi.macAddress());\r\n}\r\n \r\nvoid loop(){\r\n\t\/\/ Nothing in the Loop\r\n}\r\n\t\r\n<\/pre>\n<p><span style=\"font-weight: 400;\">As you can see, it\u2019s a very simple sketch. Run it and look on your serial monitor; the MAC address will be a series of hexadecimal numbers printed at the end of the listing.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Programming Requirements<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Now we are ready to build the sketches for both the robot and controller.\u00a0 Let\u2019s see what we want to accomplish here.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As we already know, we want the controller and robot to communicate via ESP-NOW. To do this, they need to set up a \u201cpeer-to-peer\u201d network with one another.\u00a0 Each unit will use the other units&#8217; MAC address to do this.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once the network is set up, we will establish a \u201cdata structure\u201d in both directions. This data structure specifies what information we will exchange between units.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The following diagram illustrates this, along with the data that we are exchanging.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-9199\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/program-functionality.jpg?resize=750%2C422&#038;ssl=1\" alt=\"\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/program-functionality.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/program-functionality.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Our car can execute all the Mecanum Wheel \u201cmodes,\u201d and we can control it using a joystick on the remote. The car will send back information about the speed and direction of the wheels, and we will display this on the TFT screen of our remote.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As you recall, we defined 18 different Mecanum \u201cmodes\u201d earlier. We can further divide these into smaller groups, which, to confuse things a bit more, I will also call \u201cmodes\u201d as I just can\u2019t think of a better name for them!\u00a0 For each mode, we will also have a color, which will be displayed on both the status NeoPixel LED on the car and as the background color on our controllers\u2019 display.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Standard Mecanum Mode<\/b><span style=\"font-weight: 400;\"> &#8211; The straight, sideways, and diagonal movements. In this mode, we use both the X and Y axis of the joystick to guide the vehicle.\u00a0 This mode has a status color of <\/span><b><i>Light Blue<\/i><\/b><span style=\"font-weight: 400;\">.\u00a0 This is the only mode in which the X-axis of the joystick affects the car.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Rotate Mode<\/b><span style=\"font-weight: 400;\"> &#8211; Pretty self-explanatory; in this mode, the car rotates. The Y-axis of the joystick controls both the speed and the direction of rotation. The status color for this mode is <\/span><b><i>Green<\/i><\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Pivot Right Mode<\/b><span style=\"font-weight: 400;\"> &#8211; The car will do a right-side pivot, so only the wheels on the right are driven. The mode status color is <\/span><b><i>Orange<\/i><\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Pivot Left Mode<\/b><span style=\"font-weight: 400;\"> &#8211; This time, the pivot is on the left side. The status color for pivot left is <\/span><b><i>Violet<\/i><\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Pivot Front Mode<\/b><span style=\"font-weight: 400;\"> &#8211; In this mode, only the front wheels are controlled. Once again, the Y-axis controls the speed and direction of the pivot. The status color for this mode is Pale Blue (which is slightly different from <\/span><b><i>Light Blue<\/i><\/b><span style=\"font-weight: 400;\">, trust me!).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Pivot Rear Mode<\/b><span style=\"font-weight: 400;\"> &#8211; In this final mode, the rear wheels are used to pivot. The status color for this mode is <\/span><b><i>Yellow<\/i><\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">We also have a few other conditions that we can use the status NeoPixel and\/or the TFT screen to display:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>No Controller Found<\/b><span style=\"font-weight: 400;\"> &#8211; If there is no signal from the controller, the car will have a <\/span><b><i>Red<\/i><\/b><span style=\"font-weight: 400;\"> status LED. In addition, all the motor direction NeoPixels will turn <\/span><b><i>Violet<\/i><\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>No Car Found<\/b><span style=\"font-weight: 400;\"> &#8211; If the controller cannot see the car, it will show a red error message on the TFT display.<\/span><\/li>\n<\/ul>\n<h3><span style=\"font-weight: 400;\">Robot Sketch<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I\u2019m going to break with tradition in this article, and I\u2019m not going to show you all the code, as it is very, very long! Instead, I&#8217;ll explain the functions of the individual files. <\/span><b>You can download all the code in the Resources section below<\/b><span style=\"font-weight: 400;\">, and you can also look at the video for a more detailed walk-through.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Because of the length of the code, it is divided into several files. This will make it easier to edit should you wish to expand upon it or improve it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The files, and their descriptions, are as follows:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>mec-robot-car.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The master file for the project. The declarations, the Setup, and the Loop.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>a_car-functions.ino<\/b><span style=\"font-weight: 400;\"> &#8211; Functions to move and stop the motors, also functions to control the NeoPixel LEDs.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>b_callbacks.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The ESP-NOW callback functions, called when data is sent or received.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>c_mecanum-functions.ino<\/b><span style=\"font-weight: 400;\"> &#8211; Functions that toggle and select the Mecanum Mode.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>d_mode-0.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The function that drives the car in Standard Mecanum Mode.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>e_mode-1.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The function that drives the car in Rotate Mode.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>f_mode-2-5.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The functions that drive the car in the Pivot Modes.<\/span><\/li>\n<\/ul>\n<h3><span style=\"font-weight: 400;\">Controller Sketch<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">As with the car, our controller also has its code divided into separate files for ease of use:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>mec-robot-remote.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The master file for the project. The declarations, the Setup, and the Loop. Also has two Interrupt Service Routines used with the pushbutton switches.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>a_remote-functions.ino<\/b><span style=\"font-weight: 400;\"> &#8211; A function to convert the joystick values to the proper range, allowing for error near the center of travel.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>b_callbacks.ino<\/b><span style=\"font-weight: 400;\"> &#8211; The ESP-NOW callback functions, called when data is sent or received.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>c_graphs.ino<\/b><span style=\"font-weight: 400;\"> &#8211; Functions to create the two displays (bar graph and car wheels).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>d_screens.ino<\/b><span style=\"font-weight: 400;\"> &#8211; Function to display the splash screen, which can also act as an error display screen.<\/span><\/li>\n<\/ul>\n<h3><span style=\"font-weight: 400;\">ESP-NOW Communications<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The key component in this design is the ESP-NOW peer-to-peer network that is established between the controller and the car.\u00a0 If you want to modify the design and add additional functionality (i.e., sensors, servo control), then you will need to know how to work with this component.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Structured Data<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">The data that is exchanged between the car and controller resides in a data structure that is defined on both ends.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Here is how it is defined on the car side:<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"Structured Data\">typedef struct struct_message_rcv {\r\n\u00a0\u00a0int xAxis;\r\n\u00a0\u00a0int yAxis;\r\n\u00a0\u00a0bool pbSwitch;\r\n} struct_message_rcv;\r\n\r\n\/\/ Create a structured object for received data\r\nstruct_message_rcv rcvData;\r\n\r\n\/\/ Define a data structure for sent data\r\ntypedef struct struct_message_xmit {\r\n\u00a0\u00a0byte motorMode;\r\n\u00a0\u00a0int mecanumMode;\r\n\u00a0\u00a0int mtrRF_PWM;\r\n\u00a0\u00a0int mtrLF_PWM;\r\n\u00a0\u00a0int mtrRR_PWM;\r\n\u00a0\u00a0int mtrLR_PWM;\r\n} struct_message_xmit;\r\n\r\n\/\/ Create a structured object for sent data\r\nstruct_message_xmit xmitData;<\/pre>\n<p><span style=\"font-weight: 400;\">On the controller side, it is the same, except receive and transmit are reversed.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If you wanted to send additional data, you would need to modify the structure on both sides. Keep in mind that the amount of data you can send in a data structure with ESP-NOW is small, so try and reduce your data as much as possible before sending it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can learn more about ESP-NOW in the article <\/span><a href=\"https:\/\/dronebotworkshop.com\/esp-now\/\"><span style=\"font-weight: 400;\">ESP NOW \u2013 Peer to Peer ESP32 Communications<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Callbacks<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">A key concept with ESP-NOW is callbacks. There are two callback functions, one that is called when data is sent and another that is called when data is received.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">On both ends, the receive callback is used to get the data from the data structure and pass it to local variables.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">On the car side, the send callback is used to check the status of the sent data. If it has an error, then the car is stopped and goes into an error mode, as this indicates it has lost connection with the controller.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are no send callback functions for the controller.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Sending Data<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">On both ends, the data is sent within the loop.\u00a0 It is gathered from local variables, added to the data structure, and sent with this line of code:<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"ESP-NOW Send Data\">esp_err_t result2 = esp_now_send(broadcastAddress, (uint8_t *)&amp;xmitData, sizeof(xmitData));<\/pre>\n<h2><span style=\"font-weight: 400;\">Testing the Mecanum Wheel Robot &amp; Remote<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Once you have all the code loaded, it\u2019s time to give your car a test drive.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Start by turning on the controller, and leave the car off for a moment. The controller should boot up with a splash screen, then it will show a screen saying that ESP-NOW has started. Finally, it will show an error screen indicating that the car cannot be found, which makes sense as it isn\u2019t powered up!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now turn on the car. It should go through a quick boot sequence and end up with all four motor NeoPixels turning red (which indicates that the motor has stopped) and the status light turning Light Blue, indicating that we are in Standard Mecanum Mode.\u00a0 The controller will be in bar graph mode with a Light Blue background.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now press down upon the joystick to change Mecanum Modes. Both the car status light and the display background should turn Orange, indicating that we are now in Rotate Mode.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can cycle through all the other modes, observing both the status LED and the background color on the controller.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now we can drive the car!\u00a0 I suggest starting in Standard Mecanum Mode.\u00a0 Use the joystick to maneuver the car and observe the display on the controller, as well as the motor LEDs. Try changing the display to \u201ccar mode\u201d and see how it correlates with the car LEDs.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You\u2019ll probably find that driving the car is addictive, so be sure to keep your batteries charged!<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Conclusion<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Mecanum wheels have many practical uses. Aside from that, they are fun to work with.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can certainly expand upon this design; in fact, I intend to expand it to include speed sensors soon. I\u2019ll post an update when I do.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">So have fun driving in every direction!<\/span><\/p>\n<div class=\"dbwspartsbox\">\n<h3>Parts List<\/h3>\n<p><em>Here are some components that you might need to complete the experiments in this article. Please note that some of these links may be affiliate links, and the DroneBot Workshop may receive a commission on your purchases. This does not increase the cost to you and is a method of supporting this ad-free website.<\/em><\/p>\n<ul>\n<li><strong>LilyGo TTGO ESP32<\/strong> &#8211; <a href=\"https:\/\/amzn.to\/3nJeBVd\" target=\"_blank\" rel=\"noopener\">Amazon<\/a><\/li>\n<li><strong>Espresif ESP32 DEVKIT C<\/strong> &#8211; <a href=\"https:\/\/www.digikey.com\/en\/products\/detail\/espressif-systems\/ESP32-DEVKITC-VIE\/12091811\" target=\"_blank\" rel=\"noopener\">Digikey<\/a><\/li>\n<li><strong>TB6612FNG Motor Driver<\/strong> &#8211; <a href=\"https:\/\/www.sparkfun.com\/products\/14451\" target=\"_blank\" rel=\"noopener\">Sparkfun<\/a><\/li>\n<li><strong>Mecanum Car Base<\/strong> &#8211; <a href=\"https:\/\/abra-electronics.com\/robotics\/robot-kits-en\/gk-ch-kit2-2-layer-60mm-mecanum-wheel-robot-car-chassis-kit.html\" target=\"_blank\" rel=\"noopener\">Abra Electronics<\/a><\/li>\n<\/ul>\n<\/div>\n<p>&nbsp;<\/p>\n<div class=\"dbwsresourcebox\">\n<h3>Resources<\/h3>\n<p><a href=\"https:\/\/s3.amazonaws.com\/download.dronebotworkshop.com\/Mecanum+Wheel+Car-DroneBot+Workshop.zip\">All the Code<\/a> &#8211; The code for the robot car and the remote control, as well as the test code discussed in this article<\/p>\n<p>&nbsp;<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Mecanum Wheels are unique wheels that allow you to propel a vehicle in any direction. Not just forward and backward, but sideways and diagonally as well.<\/p>\n<p>Today, we will build a robot car that uses Mecanum Wheels. Our vehicle will also have a remote control with a joystick, a TFT display, and a rechargeable battery.<\/p>\n","protected":false},"author":1,"featured_media":9205,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[92,89,4],"tags":[93],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2022\/12\/mecanum-wheels.jpg?fit=768%2C432&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/s74ClK-mecanum","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/9167"}],"collection":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/comments?post=9167"}],"version-history":[{"count":17,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/9167\/revisions"}],"predecessor-version":[{"id":9726,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/9167\/revisions\/9726"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media\/9205"}],"wp:attachment":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media?parent=9167"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/categories?post=9167"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/tags?post=9167"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}