{"id":4147,"date":"2018-05-01T16:37:40","date_gmt":"2018-05-01T20:37:40","guid":{"rendered":"https:\/\/dronebotworkshop.com\/?p=4147"},"modified":"2019-06-24T14:12:05","modified_gmt":"2019-06-24T18:12:05","slug":"xod-robot-car-1","status":"publish","type":"post","link":"https:\/\/dronebotworkshop.com\/xod-robot-car-1\/","title":{"rendered":"Getting Moving with XOD &#8211; Robot Car Part 1"},"content":{"rendered":"\n<h2><span style=\"font-weight: 400;\">Introduction<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Welcome to the second article on our series on XOD, a graphical programming IDE that allows you to rapidly develop software for the Arduino without writing any code.<\/span><\/p>\n<div class=\"youtube-player\" data-id=\"vuYet9v67oo\"><\/div>\n<p><span style=\"font-weight: 400;\">Today we\u2019ll expand upon our XOD skills and learn how to deal with projects that require nodes that don\u2019t exist. I\u2019ll show you how you can add XOD libraries to your IDE and also how to create your own custom nodes.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In order to illustrate an example of a \u201creal life design case\u201d I\u2019ve decided to start building a XPOD-powered robot car. \u00a0As the series progresses I\u2019ll add components to our robot and show you how to program your Arduino to handle these components, all with XOD of course.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Before we get started let\u2019s do a quick recap of what XOD is and how to use it.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">XOD Recap<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">In my article <\/span><a href=\"https:\/\/dronebotworkshop.com\/getting-started-with-xod\/\"><span style=\"font-weight: 400;\">Arduino Visual Programming \u2013 Getting Started with XOD<\/span><\/a><span style=\"font-weight: 400;\"> I discussed what XOD is, how to pronounce it (it is pronounced \u201czod\u201d) and how to <\/span><a href=\"https:\/\/xod.io\/downloads\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">install the desktop client<\/span><\/a><span style=\"font-weight: 400;\"> on your computer.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4182\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-part-1.jpg?resize=750%2C422&#038;ssl=1\" alt=\"XOD Robot Part 1\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-part-1.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-part-1.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;\">We then moved on to discuss the basic elements of XOD:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>Patches<\/b><span style=\"font-weight: 400;\"> &#8211; A XOD program consists of one or more patches. This is the working area where you will assemble your XOD program.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Nodes<\/b><span style=\"font-weight: 400;\"> &#8211; A node is the fundamental element of XPOD. A node can represent a logic function or an electronic component.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Pins<\/b><span style=\"font-weight: 400;\"> &#8211; All nodes have one or more pins and these can be either inputs or outputs. Inputs pins are on the top of a node while output pins are on the bottom. The pins are where you enter values for the node and are also used to connect nodes together by linking the output pin on one node to the input pin on another one.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Links<\/b><span style=\"font-weight: 400;\"> &#8211; Links are line that link the output pin of one node to an input pin on another node.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Essentially programming using the XOD IDE is performed as follows:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Determine what you want to accomplish (true in ANY programming task!).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Connect the target Arduino board to your computer via USB.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Open the XOD IDE client and start a new project.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Drag the nodes you need to accomplish your goal onto the projects patch(es).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Enter constant data into nodes where required.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Connect the nodes by creating links between specific inputs and outputs.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Save the project.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Deploy the project to the Arduino.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Observe the results and repeat as required until your goal is achieved.<\/span><\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">While XOD won\u2019t completely replace the standard <\/span><a href=\"https:\/\/www.arduino.cc\/en\/Main\/Software\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">Arduino IDE<\/span><\/a><span style=\"font-weight: 400;\"> it is still an excellent tool for rapid prototyping and for users who are more hardware savvy than code savvy. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can learn more about XOD on the <\/span><a href=\"https:\/\/xod.io\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">official XOD website<\/span><\/a><span style=\"font-weight: 400;\">. <\/span><\/p>\n<h2><span style=\"font-weight: 400;\">The XOD Robot Project<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">As we continue to learn more about XOD I thought it would be a good idea to have a project to work on. This way instead of just going through the paces of using nodes, patches and libraries we will actually have a goal that we want to achieve using XOD.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In the original article we built a small project, a temperature and humidity gauge that used an LCD display and had a push button to change from Celcius to Farenheit. \u00a0And it did a good job of illustrating just how complex a device you could construct with a simple XOD program.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">For our next project I\u2019ve decided on a robot car base. \u00a0These are always fun to work with and the results are something you can show off to anyone. A robot car base can always be expanded, and each time we add to our design we can learn new XOD techniques.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Robot That Grows<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Today we\u2019ll build the base and add a couple of components. Next time we will add more components, and we\u2019ll repeat the process a few time more until we have a complete XOD powered robot.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We will start today with just the basics &#8211; an <\/span><a href=\"https:\/\/dronebotworkshop.com\/dc-motors-l298n-h-bridge\/\"><span style=\"font-weight: 400;\">L298N H-Bridge motor controlle<\/span><\/a><span style=\"font-weight: 400;\">r and an <\/span><a href=\"https:\/\/dronebotworkshop.com\/rgb-leds\/\"><span style=\"font-weight: 400;\">RGB LED<\/span><\/a><span style=\"font-weight: 400;\">. \u00a0As time progresses we can add some of the following components:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">A Servo Motor and an HC-SR04 Ultrasonic distance sensor. This will be used to allow our robot car to avoid collisions and to \u201dself-navigate\u201d.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">IR Sensors for line-following applications.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">An audio device like a piezo buzzer or speaker.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">And the list goes on. Actually as of this writing I have no idea how this will turn out so I\u2019d welcome any other suggestions for additions to our XOD robot car.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Robot Parts<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Our robot car is built around a very common robot car base that you can easily find on eBay or Amazon. \u00a0These kits are inexpensive and are excellent value for experimenters.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The basic kit consists of a couple of an acrylic base with a number of holes and cutouts, a pair of DC motors, a rear castor to support the base, a battery holder and all of the hardware required to put it all together.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The kits also come with a pair of speed encoder discs, we won&#8217;t be using them in our initial design but might later. \u00a0If you\u2019re interested in finding out how these work please see the article <\/span><a href=\"https:\/\/dronebotworkshop.com\/robot-car-with-speed-sensors\/\"><span style=\"font-weight: 400;\">Build a Robot Car with Speed Sensors<\/span><\/a><span style=\"font-weight: 400;\"> where I show you how to use an IR source-sensor and Arduino Interrupts to read wheel speed and rotation.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You could, of course, fashion your own robot car chassis with a couple of DC motors and a homemade base. \u00a0Another option is to convert a toy vehicle.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Robot Kit Assembly<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I assembled the robot car base in the standard fashion. In my base the motors were only held in using one acrylic bracket for each motor, that seemed a bit weak (other designs use two acrylic brackets) so I put a bit of epoxy on each motor to hold them in place.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I\u2019ve decided to power the motors using the 6-volt battery pack supplied with the kit. \u00a0This breaks with tradition with me as usually I opt for a 5-cell 7.5 volt supply instead. This is because the L298N motor controller will drop 1.4 volts so with a 7.5 volt supply my motors will receive a healthy 6.1 volts (when the batteries are fresh).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The reason for electing to use the supplied 6-volt battery pack is that I intend to add a servo motor to the design and I don\u2019t want to power the servo from the 5-volt power supply derived from the Arduino. \u00a0Servo motors consume a fair bit of current and can also induce electrical noise into the power supply which could cause errors in your Arduino output.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I was concerned that the lower supply voltage would not be sufficient for my DC motors, after the voltage drop they will only be receiving 4.6 volts. \u00a0But I hooked a motor up to my bench power supply and was able to drive it with as low as 3.5 volts, so it seems like the lower voltage supply will suffice.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">For the Arduino power supply I used a USB power bank. This is a convenient method of supplying 5-volts to a project, these devices are rechargeable and can be recharged with any USB charger.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I used an Arduino Mega for this design but you could also use an Arduino Uno. I chose to use a Mega because of its extra I\/O pins and memory, although the code and hookup in this article don\u2019t require it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I also created a little \u201cpower distribution\u201d circuit board out of perfboard. It is just a convenient place to gather together all of the supply voltages (5 volts and 6 volts) and send them off to the L298N and (future) servo motor. \u00a0It also holds the RGB LED, I used a 10mm LED because I liked the way it looked but any conventional RGB LED will work just as well.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Robot Hookup<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The hookup of the XOD robot car (as it currently stands) is illustrated below. The diagram shows an Arduino Uno but if you elect to use a Mega like I did the pinouts are exactly the same.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4181\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-car-wiring.jpg?resize=750%2C422&#038;ssl=1\" alt=\"XOD robot car wiring\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-car-wiring.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-car-wiring.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;\">Most of the connections are easily made with standard hookup wires and there isn&#8217;t a lot of soldering involved. \u00a0You will need to solder the wires to the motors and you may also want to hook up a power switch for your 6-volt battery supply.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">When you connect the L298N H-Bridge be sure to remove the onboard jumper to allow the controller to be powered by the 5-volt output from the Arduino. Our 6-volt motor supply wil be insufficient to drive the L298N modules internal 5-volt voltage regulator so we need to use an external supply.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once you have it hooked up it\u2019s time to get working with XOD!<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">XOD Coding<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">I received some great comments (thank you very much!) on the original XOD article and video and one common observation was that as a XOD program grows in complexity it becomes very \u201ccluttered\u201d or \u201cbusy\u201d. \u00a0The temperature and humidity gauge we originally built was on the verge of becoming too \u201ccluttered\u201d.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Of course the same can be said of a long Arduino program written in C++, or for that matter a complex program written in any programming language.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In other languages we can resolve this issue and make our programs more readable and reuseable by writing functions and calling them from within our main program. In some programming languages we can also split our program into several files.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In XOD a good technique for avoiding this predicament is to use multiple patches. <\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Using Multiple Patches<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Every XOD program has at least one patch, by default it\u2019s called \u201cmain\u201d. \u00a0In the XOD programs we\u2019ve worked with so far it\u2019s the only patch we\u2019ve used and it contains all of our nodes and links.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">But XOD is capable of working with multiple patches. And every patch can become a node to be used in the main patch or within another patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Using the technique of multiple patches allows you to write very sophisticated XOD programs while keeping the main patch relatively clutter-free.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Another reason for using multiple patches is when you need to create a custom node for a piece of hardware that isn\u2019t currently in the \u201ccommon hardware\u201d library in your XOD IDE. \u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">To create a new patch in your XOD IDE just go to the<\/span><i><span style=\"font-weight: 400;\"> File<\/span><\/i><span style=\"font-weight: 400;\"> menu at the top of the page and choose <\/span><i><span style=\"font-weight: 400;\">New Patch<\/span><\/i><span style=\"font-weight: 400;\">. You can also use the keyboard shortcut <\/span><i><span style=\"font-weight: 400;\">Ctrl+N<\/span><\/i><span style=\"font-weight: 400;\"> on Windows or Linux or <\/span><i><span style=\"font-weight: 400;\">Command+N <\/span><\/i><span style=\"font-weight: 400;\">on the Mac.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">RGB LED<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Our RGB LED is an example of a component that does not appear in the XOD IDE common hardware library. \u00a0\u00a0While we could certainly just use three standard LEDs and that would work fine but it would be more convenient to have an RGB LED node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">So let\u2019s make one!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We\u2019ll begin by creating a new patch to work on our custom RGB LED node. Open a new patch and name it \u201c<\/span><i><span style=\"font-weight: 400;\">rgb-led<\/span><\/i><span style=\"font-weight: 400;\">\u201d (it is conventional to name patches and noided in lowercase).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Next add three LEDs. You\u2019ll find the \u201cled\u201d node in the \u201cxod\/common-hardware\u201d library. \u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">BTW, a quick way of finding the LED (and any other node) is to just double-click on a blank area of the patch, this will open up a search box that allows you to search for any XOD node. \u00a0You can also choose <\/span><i><span style=\"font-weight: 400;\">Insert Node<\/span><\/i><span style=\"font-weight: 400;\"> from the <\/span><i><span style=\"font-weight: 400;\">Edit <\/span><\/i><span style=\"font-weight: 400;\">menu to get the same search box. \u00a0Type \u201cled\u201d into the search box and click on the hresult to add an LED node to the new XOD patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once you have one LED node you can highlight it and press <\/span><i><span style=\"font-weight: 400;\">Ctrl+C <\/span><\/i><span style=\"font-weight: 400;\">(<\/span><i><span style=\"font-weight: 400;\">Command+C<\/span><\/i><span style=\"font-weight: 400;\"> on Mac) to copy it and then Ctrl+V (Command+V on Mac) twice to paste two additional copies onto the patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Each of these LED nodes represents one of the three colors in our RGB LED.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Label each of the LED nodes so you know which one is which, a simple \u201cRed, Green, Blue\u201d label should suffice.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">An LED node has two inputs and no outputs:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>PORT<\/b><span style=\"font-weight: 400;\"> &#8211; A number input, this is the pin number of the digital I\/O port on the Arduino board.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>LUM<\/b><span style=\"font-weight: 400;\"> &#8211; Also a number input, this is the luminance or brightness of the LED. It can be a value from 0 (off) to 1 (full intensity).<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">So our RGB LED custom node will need a total of six inputs, two for each LED node. In order to be able to use our patch within another patch as a custom node we will need to give it those six inputs.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Look in the Project Browser (on the left side of your XOD IDE) and navigate down to the <\/span><i><span style=\"font-weight: 400;\">xod\/patch-nodes<\/span><\/i><span style=\"font-weight: 400;\"> library. \u00a0Here you will find a number of input and output nodes made for exactly this type of application.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Since both of our LED inputs are of type \u201cnumber\u201d we will need to get six \u201c<\/span><i><span style=\"font-weight: 400;\">input-number<\/span><\/i><span style=\"font-weight: 400;\">\u201d nodes from this library and add them to our <\/span><i><span style=\"font-weight: 400;\">rgb-led<\/span><\/i><span style=\"font-weight: 400;\"> patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once you have done this add a link from each of the input-number nodes to the pins on the LED nodes. \u00a0You\u2019ll then want to label each of those input-number nodes to correspond with the pin you\u2019ve hooked it up to.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4180\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/rgb-led-patch.jpg?resize=750%2C439&#038;ssl=1\" alt=\"XOD rgb-led patch\" width=\"750\" height=\"439\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/rgb-led-patch.jpg?w=762&amp;ssl=1 762w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/rgb-led-patch.jpg?resize=300%2C176&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Save your project and return to the main patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now look in your Project Browser under <\/span><i><span style=\"font-weight: 400;\">My Project<\/span><\/i><span style=\"font-weight: 400;\">. You\u2019ll see the<\/span><i><span style=\"font-weight: 400;\"> main <\/span><\/i><span style=\"font-weight: 400;\">patch as well as the <\/span><i><span style=\"font-weight: 400;\">rgb-led<\/span><\/i><span style=\"font-weight: 400;\"> patch you just created.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Drag the <em>rgb-led<\/em> patch onto your main patch. You will see that it now resembles a node! \u00a0And best of all, it can be used just like any other node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Go into the <em>rgb-led<\/em> \u201cnode\u201d and enter in the values for the three PORT pins as follows:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R-PORT (Red PORT) &#8211; 9<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">G-PORT (Green PORT) &#8211; 10<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">B-PORT (Blue PORT) &#8211; 11<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Now adjust one or more of the LUM values so that the LED will be illuminated. \u00a0Save your work and deploy it to the Arduino.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once the program is deployed to the Arduino you should see the RGB LED illuminate in the color(s) you specified. \u00a0You\u2019ve successfully created a custom node!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">It would be a good idea to go back and add a description to each on the input pins you used to build your custom node. Do that and save your project and then look at the new node in the main window. You should see all of the pin descriptions, just like in a standard XOD node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Although adding descriptions is a bit tedious (especially for large nodes with many pins) it is a good habit to get in to as it will make the node a lot easier to use, especially months from now when you can\u2019t quite remember what all of the pins are for!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We will be using this node in our robot project further on.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Adding Libraries<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">If you\u2019ve used the Arduino IDE you\u2019re likely aware of the concept of adding libraries to the IDE to support additional hardware and functions. \u00a0The same concept exists with XOD.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can find the list of current XOD libraries on the <\/span><a href=\"https:\/\/xod.io\/libs\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">XOD website Library page<\/span><\/a><span style=\"font-weight: 400;\">. As of this writing it\u2019s not very extensive but it continues to grow as XOD users contribute libraries of their own.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In the next article in this series I\u2019ll show you how you can create your own libraries and distribute them to other members of the XOD community. \u00a0However today we will just go over obtaining and installing a new library for your XOD IDE.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">On the website the XOD libraries are listed in alphabetical order in the format \u201c<\/span><i><span style=\"font-weight: 400;\">owner\/libname<\/span><\/i><span style=\"font-weight: 400;\">\u201d with a small description of the libraries function. \u00a0Clicking on a specific library brings up a page that details the library nodes and their functions.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once you find a library that you want you\u2019ll need to add it to the XOD IDE:<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Copy the libraries \u201c<\/span><i><span style=\"font-weight: 400;\">owner\/libname<\/span><\/i><span style=\"font-weight: 400;\">\u201d string.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Open the XOD IDE.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Select <\/span><i><span style=\"font-weight: 400;\">File- Add Library<\/span><\/i><span style=\"font-weight: 400;\"> from the top menu.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">A \u201cSearch Libraries\u201d dialog box will be displayed.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Enter the \u201c<\/span><i><span style=\"font-weight: 400;\">owner\/libname<\/span><\/i><span style=\"font-weight: 400;\">\u201d string into the search box.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The library will be displayed.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Click on the library to add it to the XOD IDE.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The library will be installed.<\/span><\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">You\u2019ll find the new library listed in your Project Explorer. It is now available for use with your project and with all future XOD projects you create.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">H-Bridge Motor Control<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The L298N H-Bridge motor controller will be used to control the two DC motors used in our robot car. Naturally to use this device we will need to find a node for it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Searching through the list of installed nodes in the<\/span><i><span style=\"font-weight: 400;\"> xod\/common-hardware<\/span><\/i><span style=\"font-weight: 400;\"> library reveals an H-Bridge controller, however this one is meant to be used with the discreet L298N integrated circuit and not with the commonly available modules. You\u2019ll note that the H-Bridge used in this library has only one connection for motor direction while the common L298N modules have two.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are actually a couple of ways around this. One of them is to use the existing H-Bridge library and modify the node to add an inverter and another input (the two direction pins are always at the opposite logic state so an inverter is all we would need to correct this).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">However before we do this it is a good idea to see if someone has already created a XOD library with another H-Bridge node that supports both direction pins. And as luck would have it there is one.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The library at <\/span><i><span style=\"font-weight: 400;\">gweimer\/h-bridge<\/span><\/i><span style=\"font-weight: 400;\"> has a node called <\/span><a href=\"https:\/\/xod.io\/libs\/gweimer\/h-bridge\/h-bridge-2dir\/\" target=\"_blank\" rel=\"noopener noreferrer\"><i><span style=\"font-weight: 400;\">h-bridge-2dir<\/span><\/i><\/a><span style=\"font-weight: 400;\"> which fits the description perfectly. So let\u2019s grab that library and install in into our XOD IDE.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Follow the instruction above to install the library, use \u201c<\/span><i><span style=\"font-weight: 400;\">gweimer\/h-bridge<\/span><\/i><span style=\"font-weight: 400;\">\u201d as the search term. Once you select it the library will be downloaded and installed into your XOD IDE.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now that you have your new library let\u2019s put it to use.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Open the <\/span><i><span style=\"font-weight: 400;\">gweimer\/h-bridge<\/span><\/i><span style=\"font-weight: 400;\"> library from your Project Explorer and select the <\/span><i><span style=\"font-weight: 400;\">h-bridge-2dir<\/span><\/i><span style=\"font-weight: 400;\"> node (which in this library is the only node) and drag it onto your main patch.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The<\/span><i><span style=\"font-weight: 400;\"> h-bridge-2dir<\/span><\/i><span style=\"font-weight: 400;\"> node controls only one H-Bridge, the L298N actually is a dual H-Bridge. So make a copy of the node and paste it into your path so that you now have two nodes.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You\u2019ll probably want to edit the nodes to distinguish the two motors, I named mine \u201cMotor A\u201d and \u201cMotor B\u201d but you may want to label them differently, it\u2019s up to you.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">&lt;INSERT H-BRIDGE-2DIR DIAGRAM&gt;<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The <\/span><i><span style=\"font-weight: 400;\">h-bridge-2dir <\/span><\/i><span style=\"font-weight: 400;\">node has four pins, all inputs and all numbers:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>DIR<\/b><span style=\"font-weight: 400;\"> &#8211; The direction pin, usually connected to the IN2 (or IN4) line on the L298N module.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>!DIR<\/b><span style=\"font-weight: 400;\"> &#8211; The inverse direction pin, usually connected to IN1 (or IN3) line on the L298N module.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>PWM<\/b><span style=\"font-weight: 400;\"> &#8211; The PWM input, connected to ENA (or ENB on the L298N module.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>SPD<\/b><span style=\"font-weight: 400;\"> &#8211; The speed value. This is a number from -1 to 1 where 0 is stopped, 1 is full speed forward and -1 is full speed reverse.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">If you have hooked up your motor controller as per the diagram I presented earlier then these are the values you need to use for your<\/span><i><span style=\"font-weight: 400;\"> h-bridge-2dir<\/span><\/i><span style=\"font-weight: 400;\"> nodes:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">DIR Motor A &#8211; 4<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">!DIR Motor A &#8211; 2<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">PWM Motor A &#8211; 3<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">DIR Motor B &#8211; 8<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">!DIR Motor B &#8211; 7<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">PWM Motor B &#8211; 6<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Enter those pin values and save your project.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now select some values between -1 and 1 to enter into the SPD pins. Negative numbers make the motor spin in reverse.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Deploy your project to the Arduino. You should observe the motors rotating at the speed and direction you specified.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If you find that one of your motors is spinning in the opposite direction than what you programmed it to do it probably means you have the connections to the L298N backwards for that motor. \u00a0Reverse them to resolve the issue.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">XOD Robot Control<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">So far we have seen how to control nodes for our H-Bridge motor controllers and the RGB LED. Now it\u2019s time to expand upon our design to make our robot move and display it\u2019s LED colors as per our instructions.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In its current iteration our robot car has no sensors so it can\u2019t guilde itself by responding to sensor input. \u00a0Instead we need to give the robot a set of pre-programmed instructions and have it execute them.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As we develop our robot further we will add sensors and let the robot guide itself.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Sequential Programming<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I\u2019m using the term \u201cSequential Programming\u201d loosely here, it basically means that I want the robot programmed to execute a sequence of commands when I start it up.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Essentially I want to be able to have a number of instructions that the robot will execute in a specific order. It will execute one instruction (i.e. \u201cmove forward for three seconds at full speed) and then when it is finished it will move on to another similar instruction (i.e. turn LED on Red for four seconds). \u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I also want these instructions to repeat once they have finished. This is basically just like instructions in the \u201dloop\u201d of a standard Arduino C++ program.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A key concept in XOD is the use of \u201cpulses\u201d, in the first article in this series we used a <\/span><i><span style=\"font-weight: 400;\">square-wave<\/span><\/i><span style=\"font-weight: 400;\"> node to provide pulses to flash an LED. \u00a0Pulses are also the key to making our instructions run in a sequence.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">What we need are nodes that accept a pulse, perform an action and then output a pulse that can be used in another node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A good example of such a node is the <\/span><i><span style=\"font-weight: 400;\">xod\/core\/delay <\/span><\/i><span style=\"font-weight: 400;\">node. \u00a0This node has a SET input and a DONE output that work with pulses. Sending a pulse to the SET input causes the delay period to start. When it is done a pulse is sent out from the DONE pin.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">SET and DONE are used in several nodes and we will also use them to develop custom sequential nodes for our robot car.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">XOD Robot Code<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">In order to program our XOD robot we will need to build a couple of new custom \u201csequential\u201d nodes. Each node will have a SET pulse input and a DONE pulse output.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One node will be for our LED and the other for our H-Bridge motor controller. We can then use as many copies of these nodes as we need to program the sequence that we wish our robot to perform.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As with our original RGB LED \u201ccustom node\u201d we will be opening a new patch and using existing nodes to create our new \u201csequential\u201d or \u201cevent\u201d nodes. \u00a0Before we get started let\u2019s take a look at some of the additional nodes we will need to create our new nodes.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Boot Node<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The <\/span><a href=\"https:\/\/xod.io\/libs\/xod\/core\/boot\/\" target=\"_blank\" rel=\"noopener noreferrer\"><i><span style=\"font-weight: 400;\">Boot Node<\/span><\/i><\/a><span style=\"font-weight: 400;\"> could well be the simplest node in the entire XOD IDE, at least it\u2019s certainly a contender for that title!<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4185\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-boot-node.jpg?resize=470%2C288&#038;ssl=1\" alt=\"XOD boot node\" width=\"470\" height=\"288\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-boot-node.jpg?w=470&amp;ssl=1 470w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-boot-node.jpg?resize=300%2C184&amp;ssl=1 300w\" sizes=\"(max-width: 470px) 100vw, 470px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This node literally has only one output &#8211; a pulse called <\/span><i><span style=\"font-weight: 400;\">boot<\/span><\/i><span style=\"font-weight: 400;\">. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">The function of this node is to output a single pulse after the program starts. \u00a0Obviously this is ideal for sequencing our nodes.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We won\u2019t use this node inside one of our custom nodes, it will be used in the main node to initiate the sequence we are building. \u00a0It can be found in the <\/span><i><span style=\"font-weight: 400;\">xod\/core<\/span><\/i><span style=\"font-weight: 400;\"> library.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Defer Pulse Node<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">There are a number of nodes that are described as \u201cdefer\u201d, we will make use of <\/span><a href=\"https:\/\/xod.io\/libs\/xod\/core\/defer(pulse)\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">Defer Pulse<\/span><\/a><span style=\"font-weight: 400;\"> in both our custom nodes and in the main patch.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4186\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-defer-pulse-node.jpg?resize=750%2C349&#038;ssl=1\" alt=\"XOD defer-pulse node\" width=\"750\" height=\"349\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-defer-pulse-node.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-defer-pulse-node.jpg?resize=300%2C140&amp;ssl=1 300w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-defer-pulse-node.jpg?resize=750%2C350&amp;ssl=1 750w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-defer-pulse-node.jpg?resize=642%2C300&amp;ssl=1 642w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">All of the \u201cdefer\u201d nodes have the same function. Each node has one input and one output. When a input is received (in our case an input pulse) the defer node will wait until all the current transactions are finished before passing that input to its output.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Defer nodes are often used to create feedback loops. The defer(pulse) node can be found in the <\/span><i><span style=\"font-weight: 400;\">xod\/core<\/span><\/i><span style=\"font-weight: 400;\"> library.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Delay Node<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I mentioned the <\/span><a href=\"https:\/\/xod.io\/libs\/xod\/core\/delay\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">Delay Node<\/span><\/a><span style=\"font-weight: 400;\"> earlier, it\u2019s an important node that will be used in both of our new \u201csequential\u201d nodes so it bears looking at further.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4187\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-delay-node.jpg?resize=732%2C564&#038;ssl=1\" alt=\"XOD delay node\" width=\"732\" height=\"564\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-delay-node.jpg?w=732&amp;ssl=1 732w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-delay-node.jpg?resize=300%2C231&amp;ssl=1 300w\" sizes=\"(max-width: 732px) 100vw, 732px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">The delay node has three input pins and two output pins:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>T<\/b><span style=\"font-weight: 400;\"> &#8211; A number pin, this sets the time of the delay measured in seconds.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>SET<\/b><span style=\"font-weight: 400;\"> &#8211; This is the SET pulse input that initiates the delay.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>RST<\/b><span style=\"font-weight: 400;\"> &#8211; A Reset pulse input that can cancel the delay.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>ACT<\/b><span style=\"font-weight: 400;\"> &#8211; A boolean (i.e. true-false) output. It is True during the delay period and then goes false.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>DONE<\/b><span style=\"font-weight: 400;\"> &#8211; The DONE pulse output, this is sent when the delay period is over.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">We will use this node inside both of our new sequential nodes. It provides both the SET and DONE pulse input and output as well as an input (T) to set time. The ACT output will be used to control our new nodes.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Any Node<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The <\/span><a href=\"https:\/\/xod.io\/libs\/xod\/core\/any\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">Any Node<\/span><\/a><span style=\"font-weight: 400;\"> is a pretty simple node. It has two inputs and one output, all of type pulse.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4184\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-any-node.jpg?resize=504%2C364&#038;ssl=1\" alt=\"XOD any node\" width=\"504\" height=\"364\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-any-node.jpg?w=504&amp;ssl=1 504w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-any-node.jpg?resize=300%2C217&amp;ssl=1 300w\" sizes=\"(max-width: 504px) 100vw, 504px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">A pulse sent to either of the two inputs will result in a pulse from the houtput. It\u2019s as simple as that!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The Any node is very useful for allowing a SET input to be links to more than one output. We wil do that when we run our sequence in a loop. Like the other nodes I just described the Any node can be found in the <\/span><i><span style=\"font-weight: 400;\">xod\/core<\/span><\/i><span style=\"font-weight: 400;\"> library.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">LED Sequence Code<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">So let\u2019s begin with our first \u201csequential\u201d node, the one that controls our RGB LED.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Our new custom node will have the following input and output pins:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>T<\/b><span style=\"font-weight: 400;\"> &#8211; Time in seconds input. The length of time we want to turn on our RGB LED.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>SET<\/b><span style=\"font-weight: 400;\"> &#8211; SET Pulse input. \u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>R-PORT<\/b><span style=\"font-weight: 400;\"> &#8211; The port number for the Red segment of our RGB LED.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>R-LUM<\/b><span style=\"font-weight: 400;\"> &#8211; The luminance value for the Red LED segment. Ranges from 0 to 1.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>G-PORT<\/b><span style=\"font-weight: 400;\"> &#8211; The port number for the Green segment of our RGB LED.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>G-LUM<\/b><span style=\"font-weight: 400;\"> &#8211; The luminance value for the Green LED segment. Ranges from 0 to 1.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>B-PORT<\/b><span style=\"font-weight: 400;\"> &#8211; The port number for the Blue segment of our RGB LED.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>B-LUM<\/b><span style=\"font-weight: 400;\"> &#8211; The luminance value for the Blue LED segment. Ranges from 0 to 1.<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>DONE<\/b><span style=\"font-weight: 400;\"> &#8211; DONE Pulse output.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Operation of this node is pretty simple. We start by sending it a SET pulse. The node is then activated for the time period specified by the \u201cT\u201d value. During this time the RGB LED will glow with the colors and intensities specified in the R-LUM, G-LUM and B-LUM values. \u00a0When the time period has expired the RGB LED will be turned off and the node will emit a DONE pulse.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4178\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-rgb-led-display-patch.jpg?resize=750%2C479&#038;ssl=1\" alt=\"XOD event-rgb-led-display patch\" width=\"750\" height=\"479\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-rgb-led-display-patch.jpg?w=760&amp;ssl=1 760w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-rgb-led-display-patch.jpg?resize=300%2C191&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Follow these steps and the diagram above to create your new node. Note that I am naming it event-rgb-led-display, the term \u201cevent\u201d is to specify that this node is not constantly activated but is instead an event in time. You cabn, of course, name it anything you wish.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Create a new patch (<\/span><i><span style=\"font-weight: 400;\">File &#8211; New Patch<\/span><\/i><span style=\"font-weight: 400;\"> or <\/span><i><span style=\"font-weight: 400;\">Ctrl+N<\/span><\/i><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name patch<\/span><i><span style=\"font-weight: 400;\"> event-rgb-led-display.<\/span><\/i><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">rgb-led <\/span><\/i><span style=\"font-weight: 400;\">node (from the patch you created earlier).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">core\/delay <\/span><\/i><span style=\"font-weight: 400;\">node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input pulse node to delay node SET input<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit new <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: SET<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201cdelay\u201d node SET description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-number <\/span><\/i><span style=\"font-weight: 400;\">node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Make 6 more copies of input-number node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link original input number node to delay node T input.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit original <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-number <\/span><\/i><span style=\"font-weight: 400;\">node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name : T<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201cdelay\u201d node T description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add 3 <\/span><i><span style=\"font-weight: 400;\">core\/if-else<\/span><\/i><span style=\"font-weight: 400;\"> nodes<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link R output from each if-else node to \u201cLUM\u201d inputs on rgb-led node<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R to R-LUM<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R to G-LUM<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R to B-LUM<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to R-PORT input on rgb-led node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: R-PORT<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node R-PORT description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to G-PORT input on rgb-led node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: G-PORT<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node G-PORT description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to B-PORT input on rgb-led node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: B-PORT<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node B-PORT description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Linkt input-number node to T input on first if-else node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: R-LUM<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node R-LUM description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to T input on second if-else node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name:G-LUM<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node G-LUM description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to T input on third if-else node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit input-number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: B-LUM<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201crgb-led\u201d node B-LUM description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link ACT output of delay node to COND inputs on all three if-else nodes<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">core\/defer<\/span><\/i><span style=\"font-weight: 400;\"> pulse node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link DONE output on delay node to IN input on defer node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add<\/span><i><span style=\"font-weight: 400;\"> patch-nodes\/output-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link OUT output from defer node to output-pulse node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/output-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: DONE<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Save project<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Now that you&#8217;ve built your new RGB LED Display it\u2019s time to put it to the test.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Go back into the main patch. If you have any nodes or links still left in the main patch then delete them.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In your Project Explorer you will now see you<\/span><i><span style=\"font-weight: 400;\">r event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> patch. Drag it onto the main patch and look at it\u2019s properties. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Fill in the values for R-PORT, G-PORT and B-PORT, they are the same as the values you used for the original RGB LED node you built. \u00a0Select a period of time (in seconds) that you wish to illuminate the RGB LED and set the R-LUM, G-LUM and B-LUM values to the color levels you desire.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now take a <\/span><i><span style=\"font-weight: 400;\">core\/boot<\/span><\/i><span style=\"font-weight: 400;\"> node (the one we described earlier) and add it to the main patch. Connect its output to the SET input on your new <\/span><i><span style=\"font-weight: 400;\">event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> node. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Save the project and then deploy it to your Arduino on the robot.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You should see the LED illuminate for the time you specified and at the color combination you chose.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now make a few copies of your new node, I made two when I did this. \u00a0Go into each node and set the LUM and T values to be different than the original. The PORT values will be correct as this is a copy of a node you already configured.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Chain your nodes together by linking the DONE output of one node to the SET input on the next one. Then save and deploy your project.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You should see the RGB LED sequence working. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">In some cases you may NOT get the first sequence, I ran into that a few times. The solution seems to be to add a<\/span><i><span style=\"font-weight: 400;\"> defer(pulse)<\/span><\/i><span style=\"font-weight: 400;\"> node between the <\/span><i><span style=\"font-weight: 400;\">boot <\/span><\/i><span style=\"font-weight: 400;\">node and the first <\/span><i><span style=\"font-weight: 400;\">event-rgb-display <\/span><\/i><span style=\"font-weight: 400;\">node.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Working in a Loop<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The program we just ran did exactly what we wanted, it illuminated the RGB LED for a period of time. Then it finished. \u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This is the same effect you would have using the regular Arduino IDE and placing all of your code in the setup function and none in the loop. \u00a0And for some applications it\u2019s exactly what we want to do.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">However many times we want our code to continuously run, just as if it were in the loop in a Arduino C++ program.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can\u2019t just connect the DONE output of the fina<\/span><i><span style=\"font-weight: 400;\">l event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> node to the SET input of the first one, trying to do that will result in an error as XOD does not allow multiple connections to an input pin.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Sounds like a job for the <\/span><i><span style=\"font-weight: 400;\">any<\/span><\/i><span style=\"font-weight: 400;\"> node! \u00a0Get one from your xod\/core library and place it on your main patch, close to the <\/span><i><span style=\"font-weight: 400;\">boot<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Connect your final DONE output to a defer(pulse) node input. Connect the defer(pulse) output to one of the <\/span><i><span style=\"font-weight: 400;\">any<\/span><\/i><span style=\"font-weight: 400;\"> node inputs.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Now break the link between the <\/span><i><span style=\"font-weight: 400;\">boot<\/span><\/i><span style=\"font-weight: 400;\"> node output and the first <\/span><i><span style=\"font-weight: 400;\">event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> node SET input. \u00a0Connect the output of the <\/span><i><span style=\"font-weight: 400;\">boot <\/span><\/i><span style=\"font-weight: 400;\">node to the remaining input on the <\/span><i><span style=\"font-weight: 400;\">any<\/span><\/i><span style=\"font-weight: 400;\"> node. Connect the output of the <\/span><i><span style=\"font-weight: 400;\">any<\/span><\/i><span style=\"font-weight: 400;\"> node to the SET input on the first <\/span><i><span style=\"font-weight: 400;\">event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Save the project and deploy it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Your RGB LED should now display the sequence continuously.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We can use a similar technique to create a sequential node for our H-Bridge motor controller.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Motor Sequence Code<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">We will now do pretty well the same thing we did for our RGB LEDs for our motors. In fact the design is almost identical.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Our motor sequence node, which I am calling event-motor-move, will have the following pins:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">T &#8211; Time in seconds for the motors to run.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">SET &#8211; The SET input to start the motors running.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">DIR-A &#8211; The DIR pin for Motor B. You could also label this IN2 if you like.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">!DIR-A &#8211; The !DIR pin for Motor B. You could also label this IN1 instead to match your L298N motor controller.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">PWM-A &#8211; The PWM pin for Motor A. You could also label this ENA.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">SPD-A &#8211; The speed value for Motor A, a value from -1 to 1.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">DIR-B &#8211; The DIR pin for Motor B. You could also label this IN4 if you like.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">!DIR-B &#8211; The !DIR pin for Motor B. You could also label this IN3 instead to match your L298N motor controller.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">PWM-B &#8211; The PWM pin for Motor B. You could also label this ENB.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">SPD-B &#8211; The speed value for Motor B, a value from -1 to 1.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">DONE &#8211; The output pin for the DONE pulse.<\/span><\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4177\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-motor-move-patch.jpg?resize=750%2C446&#038;ssl=1\" alt=\"XOD event-motor-move patch\" width=\"750\" height=\"446\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-motor-move-patch.jpg?w=761&amp;ssl=1 761w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/event-motor-move-patch.jpg?resize=300%2C179&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">To construct this node follow the diagram and\/or the steps below.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Create a new patch (<\/span><i><span style=\"font-weight: 400;\">File &#8211; New Patch<\/span><\/i><span style=\"font-weight: 400;\"> or <\/span><i><span style=\"font-weight: 400;\">Ctrl+N<\/span><\/i><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name patch<\/span><i><span style=\"font-weight: 400;\"> event-motor-move.<\/span><\/i><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add 2 <\/span><i><span style=\"font-weight: 400;\">gweimer\/h-bridge<\/span><\/i><span style=\"font-weight: 400;\">\/<\/span><i><span style=\"font-weight: 400;\">h-bridge-2dir <\/span><\/i><span style=\"font-weight: 400;\">nodes (from the library you downloaded earlier).<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label one h-bridge node \u201cMotor A\u201d.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label second h-bridge node \u201cMotor B\u201d.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">core\/delay <\/span><\/i><span style=\"font-weight: 400;\">node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input pulse node to delay node SET input<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit new <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: SET<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201cdelay\u201d node SET description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-number <\/span><\/i><span style=\"font-weight: 400;\">node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Make 8 more copies of input-number node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link original input number node to delay node T input.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit original <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/input-number <\/span><\/i><span style=\"font-weight: 400;\">node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name : T<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description &#8211; copy from \u201cdelay\u201d node T description<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add 2 <\/span><i><span style=\"font-weight: 400;\">core\/if-else<\/span><\/i><span style=\"font-weight: 400;\"> nodes<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link R output from each if-else node to \u201cSPD\u201d inputs on rgb-led node<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R to SPD on Motor A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">R to SPD on Motor B<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to DIR input on Motor A node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: DIR-A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor A node DIR pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to !DIR input on Motor A node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: !DIR-A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor A node !DIR pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to PWM input on Motor A node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: PWM-A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor A node PWM pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to DIR input on Motor B node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: DIR-B<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor B node DIR pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to !DIR input on Motor B node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: !DIR-B<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor B node !DIR pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to PWM input on Motor B node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: PWM-B<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor B node PWM pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to T input on first if-else node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: SPD-A<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor A node SPD pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link input-number node to T input on second if-else node<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Label input number node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: SPD-B<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Description; Copy description from Motor B node SPD pin.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Connect COND inputs on both if-else nodes to ACT output on delay node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add <\/span><i><span style=\"font-weight: 400;\">core\/defer<\/span><\/i><span style=\"font-weight: 400;\"> pulse node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link DONE output on delay node to IN input on defer node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Add<\/span><i><span style=\"font-weight: 400;\"> patch-nodes\/output-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Link OUT output from defer node to output-pulse node.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Edit <\/span><i><span style=\"font-weight: 400;\">patch-nodes\/output-pulse<\/span><\/i><span style=\"font-weight: 400;\"> node:<\/span>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Name: DONE<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Save project<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Now go back to your main patch and drag a new <\/span><i><span style=\"font-weight: 400;\">event-motor-move<\/span><\/i><span style=\"font-weight: 400;\"> node onto it. Fill in the values for the connections to the L298N H-Bridge. \u00a0Also set some speed and time values.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-4179\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/main-patch.jpg?resize=693%2C720&#038;ssl=1\" alt=\"XOD main patch\" width=\"693\" height=\"720\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/main-patch.jpg?w=693&amp;ssl=1 693w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/main-patch.jpg?resize=289%2C300&amp;ssl=1 289w\" sizes=\"(max-width: 693px) 100vw, 693px\" data-recalc-dims=\"1\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Link one of the DONE outputs from one of the <\/span><i><span style=\"font-weight: 400;\">event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> nodes to the SET input of your <\/span><i><span style=\"font-weight: 400;\">event-motor-move<\/span><\/i><span style=\"font-weight: 400;\"> node. Link the output to another <\/span><i><span style=\"font-weight: 400;\">event-rgb-led-display<\/span><\/i><span style=\"font-weight: 400;\"> node.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can make copies of the new node, change their values and link them into the sequence.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">When you are done save the project and deploy it to the robot. Make sure the robot car is in a place where you can actually run it, or lift it off the workbench so that it doesn\u2019t run away on you!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Your XOD powered robot car can now run around the room!<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Conclusion<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">As this article and its associated video have hopefully illustrated it is possible to create complex projects using XOD without your screen becoming as complex as a map of Manhattan! <\/span><\/p>\n<p><span style=\"font-weight: 400;\">I hope you decide to build the XOD robot and stay tuned for more installments, as I think it will be a really fun project.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Let me know about your XOD projects in the comments below. Happy Xoding!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Resources<\/span><\/p>\n<p><a href=\"https:\/\/xod.io\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">XOD Website<\/span><\/a><span style=\"font-weight: 400;\"> &#8211; The XOD website, the primary source for information regarding XOD.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Code from this Article &#8211; The .xodball files I used in this article, in a convenient ZIP file for you!<\/span><\/p>\n<p><a href=\"https:\/\/xod.io\/libs\/\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"font-weight: 400;\">XOD Libraries<\/span><\/a><span style=\"font-weight: 400;\"> &#8211; The XOD Library page.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>XOD is a method of programming an Arduino using a graphical IDE instead of writing code.  In XOD you use a collection of \u201cnodes\u201d connected by \u201clinks\u201d to program your Arduino.<\/p>\n<p>In this second installment on our series on XOD I\u2019ll show you some ways of improving your XOD projects by using multiple patches, custom nodes and XOD libraries.<\/p>\n<p>But the real fun is that in this article we\u2019ll also start working on a practical project &#8211; a XOD robot! So let\u2019s get started.<\/p>\n","protected":false},"author":1,"featured_media":4182,"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":[9,4,6,90],"tags":[45,52,55],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2018\/05\/xod-robot-part-1.jpg?fit=768%2C432&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p74ClK-14T","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/4147"}],"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=4147"}],"version-history":[{"count":0,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/4147\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media\/4182"}],"wp:attachment":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media?parent=4147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/categories?post=4147"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/tags?post=4147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}