{"id":6620,"date":"2019-11-24T11:52:58","date_gmt":"2019-11-24T16:52:58","guid":{"rendered":"https:\/\/dronebotworkshop.com\/?p=6620"},"modified":"2023-04-12T11:06:55","modified_gmt":"2023-04-12T15:06:55","slug":"laser-vs-ultrasonic-distance-sensor-tests","status":"publish","type":"post","link":"https:\/\/dronebotworkshop.com\/laser-vs-ultrasonic-distance-sensor-tests\/","title":{"rendered":"LASER vs Ultrasonic &#8211; Distance Sensor Tests"},"content":{"rendered":"\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-9571 size-full alignnone\" 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 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\/xO5_3SjEhS4\" 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\/LASER+vs+Ultrasonic+-+DroneBot+Workshop.zip\"><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\u2019re having a contest of sorts, a match between two popular types of distance sensors. Get ready to place your bets on the winner!<\/span><\/p>\n<div class=\"youtube-player\" data-id=\"xO5_3SjEhS4\"><\/div>\n<p><span style=\"font-weight: 400;\">I\u2019ve got a bit of a different type of experiment going on in the workshop today, it\u2019s a battle between two types of distance sensors. One of them uses lasers and is extremely small, and the other is <a href=\"https:\/\/dronebotworkshop.com\/hc-sr04-ultrasonic-distance-sensor-arduino\/\">our old friend the HC-SR04<\/a> which chirps out ultrasonic sound waves.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We\u2019ll compare the performance of these sensors in the special DroneBot Workshop Distance Tester, constructed especially for this article and video!\u00a0<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6612\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-vs-tof10120.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 vs TOF10120\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-vs-tof10120.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-vs-tof10120.jpeg?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\u2019ll compare both devices for accuracy in the 10 &#8211; 100 cm range, against both reflective and absorbent surfaces.\u00a0 We\u2019ll also compare the spec sheets to see where each sensor shines.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Come and get a good seat for the match and we\u2019ll get started!<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Distance Sensing<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Distance Sensing is a common and even critical function in many modern designs. It\u2019s used extensively in robotics but also finds use in a variety of different applications such as security sensors, process control designs, quadcopters, and vehicle safety systems.\u00a0 It even finds a home in hands-free bathroom fixtures.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We have discussed these types of sensors before, including an extensive article about using the popular HC-SR04 ultrasonic distance sensor.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">All of these types of sensors use the same basic principle, they just execute it differently:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">A signal is transmitted at the target from the sensor.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The target reflects the signal back to the sensor.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The sensor receives the reflected signal.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The time delay between the sending of the signal and its reception is used to calculate the distance to the target.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">The HC-SR04 used ultrasonic sound at a frequency of about 40 kHz, too high for us humans to hear but potentially audible to some animals. Fifi and Fido beware!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Sound is only one of many different mediums that you can use to do this trick. The most well-known application of this principle is RADAR, which uses microwaves.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Light is also a popular method of building a distance sensor. We have already seen this used in a very advanced way when we discussed using LiDAR a while back.\u00a0\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Light sensors have several advantages over their ultrasonic counterparts. They can be made very small and can be waterproof. And because the speed of light is so much quicker than sound, light sensors can respond very quickly and can be queried more often.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">But light sensors also require advanced electronics, capable of measuring the incredibly small time differences encountered when working with light.\u00a0 Consider this:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">In one second sound will travel 343 meters (0.343 Km), a little longer than three American football fields placed end-to-end.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">In one second light will travel\u00a0 299,792,458 meters (299,792.458 Km), about three quarters the distance from the Earth to the Moon.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Advanced light sensors make use of lasers, combine that with the high-speed electronics and the cost of light sensors can be substantially higher than ultrasonic sensors.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Ultrasonic sensors also have some advantages over light sensors. Not only are they lower in cost, they generally have longer measurement ranges, at least in low-cost sensors.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Each type has advantages and disadvantages in different environments, and both can be subject to external interference.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In robotics, it is common to use both types to get the advantages of each type of sensor.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Our Contestants &#8211; HC-SR04 vs. TOF10120<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">It\u2019s time now to meet today&#8217;s contestants &#8211; yes that did sound a bit like a game show host speaking, didn\u2019t it?\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">We have our old friend the HC-SR04 Ultrasonic Sensor pitted up against the newcomer, a TOF10120 Laser range finder. This new guy is being offered on all the usual channels (Amazon, eBay, etc) and is very, very tiny.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Testing Parameters<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I\u2019m not expecting any real winners or losers today, as each sensor has its strengths and weaknesses. Here is what we\u2019ll be comparing:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><b>Cost<\/b><span style=\"font-weight: 400;\"> &#8211; How expensive is the device?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Interface<\/b><span style=\"font-weight: 400;\"> &#8211; How does the sensor connect up to your microcontroller?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Size &amp; Weight<\/b><span style=\"font-weight: 400;\"> &#8211; How large is the sensor, how much does it weigh?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Current <\/b><span style=\"font-weight: 400;\">&#8211; How much current does the sensor consume?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Maximum Rated Range<\/b><span style=\"font-weight: 400;\"> &#8211; What is the maximum range the sensor can detect?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Minimum Rated Range<\/b><span style=\"font-weight: 400;\"> &#8211; What is the minimum range the sensor can detect?<\/span><\/li>\n<li style=\"font-weight: 400;\"><b>Range Test<\/b><span style=\"font-weight: 400;\"> &#8211; A test of the sensor at 5 preset distances, each with two different target surfaces.\u00a0 How accurate are they?<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Let&#8217;s take a closer look at the two sensors.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">HC-SR04<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The HC-SR04 is a very popular ultrasonic distance sensor. It is widely available and is a staple of low-cost collision-avoidance robots.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6609\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-features.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 features\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-features.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-features.jpeg?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 a very versatile sensor, I have done a complete article and video devoted solely to the HC-SR04 as it is such an important component.\u00a0 <a href=\"https:\/\/dronebotworkshop.com\/hc-sr04-ultrasonic-distance-sensor-arduino\/\">If you want to bring yourself up to speed on the HC-SR04, then that article is a great place to start<\/a>.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6610\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-pinouts.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 Pinouts\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-pinouts.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-pinouts.jpeg?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 HC-SR04 is pretty simple to use. It has four pins:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">VCC &#8211; Power, +5 VDC<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Trig &#8211; the Trigger input, the input that you use to initiate a measurement. Each time you input a pulse of at least 10ms the sensor sends eight sets of 40 kHz pulses.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Echo &#8211; The received pulse. It stays HIGH while the sensor waits for returned reflection data.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">GND &#8211; Ground<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">You can tie the Trigger and Echo pins together and use the sensor in \u201c3-wire mode\u201d to save on an I\/O pin.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The HC-SR04 has a rated range of 2-400 cm.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">TOF10120<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The TOF10120 is a Laser \u201ctime of flight\u201d sensor that uses VCSEL (Vertical-Cavity Surface-Emitting Laser) technology to measure distance.\u00a0 It is a very tiny device, measuring only 20 * 13 * 5 mm.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6616\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-features.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 features\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-features.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-features.jpeg?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 device has a multitude of uses, including in those appliances like hand dryers and automatic sinks which use the sensor to detect movement.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This device communicates over I2C, it also has a serial connection.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The TOF10120 comes complete with an interface cable for use during experiments. It brings out the 6 pins on the sensor. The cable is color-coded as follows:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6619\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-pinouts.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 Pinouts - Color Coded\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-pinouts.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-pinouts.jpeg?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 device operates on voltages between 3 and 5-volts, so it is suitable for use with 3.3-volt logic.\u00a0 It has a stated range of 10 &#8211; 180 cm.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Comparing the two Devices<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">As these devices use different technologies (sound vs. light) to achieve their goals they each have specific advantages and disadvantages. Here are a few things to consider when choosing which one to use:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6611\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-tof10120-compare.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 - TOF10120 Compared\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-tof10120-compare.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-tof10120-compare.jpeg?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;\"><span style=\"font-weight: 400;\">The HC-SR04 is less expensive you can buy several of them for the price of one TOF10120.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The TOF10120 is a sealed unit and is ideal for applications where moisture or dirt may be present.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The TOF10120 is much smaller than the HC-SR04.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">As light travels much faster than sound the TOF10120 responds much quicker than the HC-SR04.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The HC-SR054 has a wider field of view, which may or may not be a disadvantage, depending upon your application.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">The TOF10120 can be used with 3.3-volt or 5-volt logic. The HC-SR04 can only be used with 5-volt logic.<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">Currently, there is very little English documentation for the TOF10120.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Having said all that, either unit would be a good choice for many common applications.\u00a0<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6617\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-hcsr04-compare-size.jpg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 vs HC-SR04 size comparison\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-hcsr04-compare-size.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-hcsr04-compare-size.jpg?resize=300%2C169&amp;ssl=1 300w\" sizes=\"(max-width: 750px) 100vw, 750px\" data-recalc-dims=\"1\" \/><\/p>\n<h2><span style=\"font-weight: 400;\">Sensor Test Sketches<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">To run our tests, we will need a sketch for each of the sensors.\u00a0 Nothing fancy, just something that will read the sensor and report the reading on the serial monitor will be sufficient.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">So before we move to the testbed we will first hook up our two sensors and check them out with a simple sketch.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">HC-SR04 Hookup<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">I\u2019m going to use one of the experiments I performed in the article and video I made about the HC-SR04 as my test sketch for the ultrasonic sensor. And I\u2019m going to add an additional component as well.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6607\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-dht22-hookup.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04, DHT-22 and Arduino Hookup\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-dht22-hookup.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-dht22-hookup.jpeg?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 extra part is a DHT-22 temperature and humidity sensor. I\u2019m adding this because the speed of sound is influenced by environmental factors like temperature and humidity, so I wanted to factor that in when calculating distance.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I\u2019m running the HC-SR04 in a 4-wire mode in this hookup.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">HC-SR04 Code<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">This sketch is an old one from early 2017, however, it serves its purpose.<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"HC-SR04 with DHT-22\">\/*\r\n  HC-SR04 with Temp and Humidity Demonstration\r\n  HC-SR04-Temp-Humid-Demo.ino\r\n  Demonstrates enhancements of HC-SR04 Ultrasonic Range Finder\r\n  With DHT22 Temperature and Humidity Sensor\r\n  Displays results on Serial Monitor\r\n\r\n  DroneBot Workshop 2017\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"ncVLtkJd1G\"><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=fDdlusOcMO#?secret=ncVLtkJd1G\" data-secret=\"ncVLtkJd1G\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n\/\/ Include DHT Libraries from Adafruit\r\n\/\/ Dependant upon Adafruit_Sensors Library\r\n#include \"DHT.h\";\r\n\r\n\/\/ Include NewPing Library\r\n#include \"NewPing.h\"\r\n\r\n\/\/ Define Constants\r\n\r\n#define DHTPIN 7       \/\/ DHT-22 Output Pin connection\r\n#define DHTTYPE DHT22   \/\/ DHT Type is DHT 22 (AM2302)\r\n#define TRIGGER_PIN  10\r\n#define ECHO_PIN     13\r\n#define MAX_DISTANCE 400\r\n\r\nNewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);\r\n\r\n\/\/ Define Variables\r\n\r\nfloat hum;    \/\/ Stores humidity value in percent\r\nfloat temp;   \/\/ Stores temperature value in Celcius\r\nfloat duration; \/\/ Stores HC-SR04 pulse duration value\r\nfloat distance; \/\/ Stores calculated distance in cm\r\nfloat soundsp;  \/\/ Stores calculated speed of sound in M\/S\r\nfloat soundcm;  \/\/ Stores calculated speed of sound in cm\/ms\r\nint iterations = 5;\r\n\r\n\/\/ Initialize DHT sensor for normal 16mhz Arduino\r\n\r\nDHT dht(DHTPIN, DHTTYPE); \r\n\r\nvoid setup() {\r\n  Serial.begin (9600);\r\n  dht.begin();\r\n}\r\n\r\nvoid loop()\r\n{\r\n\r\n  delay(2000);  \/\/ Delay so DHT-22 sensor can stabalize\r\n   \r\n    hum = dht.readHumidity();  \/\/ Get Humidity value\r\n    temp= dht.readTemperature();  \/\/ Get Temperature value\r\n    \r\n    \/\/ Calculate the Speed of Sound in M\/S\r\n    soundsp = 331.4 + (0.606 * temp) + (0.0124 * hum);\r\n    \r\n    \/\/ Convert to cm\/ms\r\n    \r\n    soundcm = soundsp \/ 10000;\r\n    \r\n  duration = sonar.ping_median(iterations);\r\n  \r\n  \/\/ Calculate the distance\r\n  distance = (duration \/ 2) * soundcm;\r\n  \r\n  \/\/ Send results to Serial Monitor\r\n  \r\n    Serial.print(\"Sound: \");\r\n    Serial.print(soundsp);\r\n    Serial.print(\" m\/s, \");\r\n    Serial.print(\"Humid: \");\r\n    Serial.print(hum);\r\n    Serial.print(\" %, Temp: \");\r\n    Serial.print(temp);\r\n    Serial.print(\" C, \");\r\n    Serial.print(\"Distance: \");\r\n\r\n    if (distance &gt;= 400 || distance &lt;= 2) {\r\n    Serial.print(\"Out of range\");\r\n    }\r\n    else {\r\n    Serial.print(distance);\r\n    Serial.print(\" cm\");\r\n    delay(500);\r\n    }\r\n  \r\n  Serial.println(\" \");\r\n}\r\n<\/pre>\n<p><span style=\"font-weight: 400;\">The sketch requires three libraries, as the <\/span><i><span style=\"font-weight: 400;\">Adafruit DHT Library<\/span><\/i><span style=\"font-weight: 400;\"> is dependent upon the <\/span><i><span style=\"font-weight: 400;\">Adafruit Universal Sensor Library<\/span><\/i><span style=\"font-weight: 400;\">. Both libraries can be installed using your Arduino IDE Library Manager.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You\u2019ll also need to install the <\/span><i><span style=\"font-weight: 400;\">NewPing Library<\/span><\/i><span style=\"font-weight: 400;\">, again you can install this by searching for it in the Library Manager.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The sketch is pretty simple, if you&#8217;d like a detailed explanation of it please see the original article about using the HC-SR04.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Most of the action in the sketch goes on in the Loop. The first thing that occurs here is the temperature and humidity are read from the DHT-22. These are then used to calculate the speed of sound in centimeters per millisecond, factoring in temperature and humidity.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This value is applied to the HC-SR04 time delay reading, which is then divided in half to determine the distance.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You\u2019ll note that there are a couple of time delays applied to the readings, to allow both the DHT-22 and HC-SR04 to stabilize between readings.\u00a0 This adds up to a total delay of about 2.5 seconds, so that\u2019s how often we can expect a reading.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The results of the distance equation, as well as the temperature and humidity readings, are displayed on the serial monitor.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">HC-SR04 Quick Check<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">So let\u2019s give the ultrasonic sensor a quick test.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6606\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-basic-test.jpg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 Basic Test\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-basic-test.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-basic-test.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;\">Hook up everything as shown in the diagram and load the sketch, being sure to remember to install the three libraries first.\u00a0 Then use a test object as a target, I used a notepad when I did this.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The resulting readings seemed reasonable, so I\u2019ll consider our HC-SR04 to be working properly.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">TOF10120 Hookup<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">Hooking up the TOF10120 is very simple, thanks to the cable provided with the unit. As the cable uses female Dupont pins I just used small jumper wires to connect it directly to my Arduino.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6613\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-arduino-hookup.jpeg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 Arduino hookup\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-arduino-hookup.jpeg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-arduino-hookup.jpeg?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;\">As we are using the I2C connection there are only four connections to the Arduino &#8211; power, ground, SDA, and SCL.\u00a0 I did not use pull-up resistors and everything seemed to work correctly.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are two other connections to the sensor serial port that are left unconnected in this experiment.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">TOF10120 Code<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">One difficulty in working with the TOF10120 is a lack of documentation. While there is a wealth of documentation, app notes and sample code for the HC-SR04 there is very little available for the TOF10120, at least in English.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The following code came from a YouTube user named \u201cSurtrTech\u201d who claims he\/she obtained it from a Chinese website. Unfortunately, no link to the actual source was provided, so I can\u2019t credit the original author.<\/span><\/p>\n<pre class=\"lang:default decode:true \" title=\"TOF10120 Test Sketch\">\/*\r\n  TOF10120 Distance Sensor Demonstration\r\n  TOF10120-Demo.ino\r\n  Demonstrates use of TOF10120 Distance Sensor\r\n  Adapted from code from SurtrTech\r\n  Displays results on Serial Monitor\r\n\r\n  DroneBot Workshop 2019\r\n  <blockquote class=\"wp-embedded-content\" data-secret=\"8lg0O9mU2j\"><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=9k0OUyrQ1b#?secret=8lg0O9mU2j\" data-secret=\"8lg0O9mU2j\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\r\n*\/\r\n\r\n#include &lt;Wire.h&gt;\r\n\r\nunsigned char ok_flag;\r\nunsigned char fail_flag;\r\n\r\nunsigned short lenth_val = 0;\r\nunsigned char i2c_rx_buf[16];\r\nunsigned char dirsend_flag=0;\r\n\r\n\r\nvoid setup() {\r\n  Wire.begin(); \r\n  Serial.begin(9600,SERIAL_8N1); \r\n  printf_begin();          \r\n\r\n}\r\n\r\nvoid loop() {\r\n  \r\n\r\n   int x=ReadDistance();\r\n   \r\n   Serial.print(x);\r\n   Serial.println(\" mm\");\r\n  \r\n}\r\n\r\nint serial_putc( char c, struct __file * )\r\n{\r\n  Serial.write( c );\r\n  return c;\r\n}\r\n\r\nvoid printf_begin(void)\r\n{\r\n  fdevopen( &amp;serial_putc, 0 );\r\n}\r\n\r\n\r\n\r\nvoid SensorRead(unsigned char addr,unsigned char* datbuf,unsigned char cnt) \r\n{\r\n  unsigned short result=0;\r\n  \/\/ step 1: instruct sensor to read echoes\r\n  Wire.beginTransmission(82); \/\/ transmit to device #82 (0x52)\r\n  \/\/ the address specified in the datasheet is 164 (0xa4)\r\n  \/\/ but i2c adressing uses the high 7 bits so it's 82\r\n  Wire.write(byte(addr));      \/\/ sets distance data address (addr)\r\n  Wire.endTransmission();      \/\/ stop transmitting\r\n  \/\/ step 2: wait for readings to happen\r\n  delay(1);                   \/\/ datasheet suggests at least 30uS\r\n  \/\/ step 3: request reading from sensor\r\n  Wire.requestFrom(82, cnt);    \/\/ request cnt bytes from slave device #82 (0x52)\r\n  \/\/ step 5: receive reading from sensor\r\n  if (cnt &lt;= Wire.available()) { \/\/ if two bytes were received\r\n    *datbuf++ = Wire.read();  \/\/ receive high byte (overwrites previous reading)\r\n    *datbuf++ = Wire.read(); \/\/ receive low byte as lower 8 bits\r\n  }\r\n}\r\n\r\nint ReadDistance(){\r\n    SensorRead(0x00,i2c_rx_buf,2);\r\n    lenth_val=i2c_rx_buf[0];\r\n    lenth_val=lenth_val&lt;&lt;8;\r\n    lenth_val|=i2c_rx_buf[1];\r\n    delay(300); \r\n    return lenth_val;\r\n}\r\n<\/pre>\n<p><span style=\"font-weight: 400;\">The sketch doesn\u2019t require any additional libraries, the only library it uses is the Arduino Wire Library which simplifies using I2C.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The real action in this sketch occurs in the <\/span><i><span style=\"font-weight: 400;\">SensorRead <\/span><\/i><span style=\"font-weight: 400;\">function. If you step through this function you\u2019ll see how the I2C bus is used to contact the sensor, request a reading and add the result to a data buffer.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Another function, <\/span><i><span style=\"font-weight: 400;\">ReadDistance<\/span><\/i><span style=\"font-weight: 400;\">, calls the <\/span><i><span style=\"font-weight: 400;\">SensorRead <\/span><\/i><span style=\"font-weight: 400;\">function every time it wants a reading. It then takes the value off the buffer, delays 300 ms and then outputs it as in integer. The integer will be the distance in millimeters.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The Loop just calls <\/span><i><span style=\"font-weight: 400;\">ReadDistance<\/span><\/i><span style=\"font-weight: 400;\"> and prints the value to the serial monitor.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">TOF10120 Quick Check<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">After wiring up the TOF10120 and loading the sketch I tested everything out, again using a notepad as a target.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6614\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-basic-test.jpg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 Basic Test\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-basic-test.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-basic-test.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 device responded quickly every time I moved my target, so it looks like it\u2019s working.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Note the two unconnected wires from the sensor, these are for the serial I\/O port.\u00a0<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Performance Tests<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Now that we have our two distance sensors working it\u2019s time to get to the actual competition!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Ideally, to do this test properly, I would have used a large room with controlled temperature, humidity and light levels. Unfortunately, that isn\u2019t feasible, so I did the tests on my workbench.\u00a0 It is certainly not as scientific, but it does represent more of a \u201creal world\u201d situation.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">DroneBot Workshop Distance Testbed<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">To conduct these tests I created the \u201cDroneBot Workshop Distance Testbed\u201d, which is an eloquent name for some scrap wood from the workshop!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The testbed consists of a 4-foot long piece of particle board that has several wood spacers glued to it. These spacers are made to hold a reflector block in several pre-measured positions.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The reflector block itself is a piece of wood with two different surfaces. On one side there is a small piece of plywood, which provides a smooth surface. On the other side, I affixed a piece of foam, the same thickness as the plywood. This provides an absorbent irregular surface.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The sensors and the Arduino Uno driving them are placed on an elevated surface at the \u201czero-point\u201d of the testbed. The surface is elevated so that the bottom board itself doesn&#8217;t interfere with the sensors.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">Testing Sequence<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">To keep things at an even playing field, I\u2019m going to calibrate each sensor at the 25 cm mark with the reflective (plywood) surface. Then we will test the sensors in all the remaining positions, with both the plywood and foam sides.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The preset positions are as follows:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">10 cm<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">25 cm<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">50 cm<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">75 cm<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">100 cm (1 meter)<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">I\u2019m limited to a one-meter test due to the size of my workbench!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">So let&#8217;s see how the two sensors performed.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">HC-SR04<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The ultrasonic sensor performed surprisingly well, although I did add the DHT-22 temperature and humidity sensor to help improve its performance.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">After calibrating the sensor at 25 cm I tested it at 10 cm and 50 cm. Both readings were well within a centimeter accuracy, which is pretty good for a cheap sensor.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6608\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-distance-test.jpg?resize=750%2C422&#038;ssl=1\" alt=\"HC-SR04 distance-test\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-distance-test.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-distance-test.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;\">After trying to move past 50 cm, however, I experienced problems. I know from previous experience that the sensor is capable of much greater distances than that, but on my testbed, I couldn\u2019t get much past the 50 cm mark.\u00a0 So all of the reading above that were pretty well meaningless.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">What I expect is happening is that the sensor is triggering on something <\/span><span style=\"font-weight: 400;\">besides<\/span><span style=\"font-weight: 400;\"> the testbed on my workbench. This sensor has a pretty wide field of view, and so it is likely hitting on either the parts cabinets or myself. After moving out of the way without any effect on the readings I\u2019m blaming the parts cabinets!<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Things got more interesting when I tried the foam side of the reflector.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As I had suspected, the sound waves don\u2019t reflect off of the foam. Instead, they are bouncing off the surface of the wooden block, passing through the foam as if it wasn\u2019t there.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As a result, the tests at 10, 25 and 50 cm were almost a centimeter off. Both my plywood and foam are a quarter-inch thick, which is about a sixth of a centimeter, and that seemed to account for the difference.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">As I knew that the tests after 50 cm were pointless I didn\u2019t bother to record them.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">What impresses me about this sensor is that it performed really well until I ran into the interference issue.\u00a0 When you consider it\u2019s price it\u2019s no wonder it\u2019s such a popular device.<\/span><\/p>\n<h3><span style=\"font-weight: 400;\">TOF10120<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The Laser time-of-flight sensor has a range of 10 cm to 180 cm, so I was curious how it would perform at the 10 cm mark.\u00a0 It has millimeter accuracy so 10 cm is 100 mm, and it came within 5 mm of the mark.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The sensor also did very well at the 50 cm mark.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6615\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-distance-test.jpg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 distance test\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-distance-test.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-distance-test.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;\">But on the higher points, 75 and 100 centimeters, the readings were off by a great deal, over 10%.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The documentation that I was able to obtain for the sensor claims that the range and accuracy are affected by many factors, including ambient light and the reflectivity of the surface being detected.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">So I tried the experiments with the lights out and with a white (and black) sheet of paper over the plywood. Neither seems to change the results.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One of the more interesting results was what happened when I used the foam side.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">I had expected that the sensor might get fooled by the foam and give erratic readings. But the readings were pretty steady, but they were all out by the same factor &#8211; the thickness of the foam.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-6618\" src=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-looking-through-foam.jpg?resize=750%2C422&#038;ssl=1\" alt=\"TOF10120 looking through foam\" width=\"750\" height=\"422\" srcset=\"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-looking-through-foam.jpg?w=768&amp;ssl=1 768w, https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/tof10120-looking-through-foam.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;\">It seems the laser beam passed right through the foam and hit the underlying board. Just as the ultrasonic sound waves did.\u00a0 I hadn\u2019t expected that.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Perhaps my foam is \u201cinvisible\u201d in infrared light?<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One thing that can\u2019t help but impress you when using this sensor is how fast the data gets updated.\u00a0 It really would be great for moving objects, like robots, quadcopters and model boats.<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">Conclusion<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Both sensors performed well in the 10 &#8211; 50 cm range, and both of them were affected by the foam side of the test target.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The ultrasonic sensor readings above 50 cm were meaningless, probably due to external interference from my workbench.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The laser sensor accuracy after 50 cm really dropped, although since my next test point was at 75 cm I \u2018m not certain exactly where the drop was.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">When factoring in the cost difference the HC-SR04 is a clear winner, providing that you don\u2019t require very fast readings or an environmentally-sealed sensor. But you also need to remember that I use dan DHT-22 temperature and humidity sensor in my circuit. If you add in the DHT-22 cost the two sensors come out to be within a couple of dollars of each other.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The high data rate of the TOF10120 is impressive, and I know I\u2019ll be making use of one in a robotics project soon.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In fact, I think an even better idea is to build a detector that uses both of these sensors, gaining the advantages of each one. I\u2019ll get to work on that right now!<\/span><\/p>\n<p>&nbsp;<\/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<p>COMING SOON!<\/p>\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\/LASER+vs+Ultrasonic+-+DroneBot+Workshop.zip\" target=\"_blank\" rel=\"noopener noreferrer\">Code for this Article<\/a> &#8211; All the code used in this article in a handy ZIP file.<\/p>\n<p><a href=\"https:\/\/s3.amazonaws.com\/download.dronebotworkshop.com\/DBWS+-+LASER+vs+Ultrasonic+%E2%80%93+Distance+Sensor+Tests.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">PDF Version<\/a> &#8211; A PDF version of this article, great for printing and using on your workbench.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Today I&#8217;m going to compare the performance of a tiny Laser-based time-of-flight sensor, the TOF10120, with the classic HC-SR04 ultrasonic range finder.<\/p>\n<p>After we hook the sensors up to an Arduino I&#8217;ll put them to the test on my &#8220;unique&#8221; testbed. The results might surprise you.<\/p>\n","protected":false},"author":1,"featured_media":6612,"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":[5],"tags":[43],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/dronebotworkshop.com\/wp-content\/uploads\/2019\/11\/hcsr04-vs-tof10120.jpeg?fit=768%2C432&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p74ClK-1IM","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/6620"}],"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=6620"}],"version-history":[{"count":2,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/6620\/revisions"}],"predecessor-version":[{"id":9918,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/posts\/6620\/revisions\/9918"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media\/6612"}],"wp:attachment":[{"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/media?parent=6620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/categories?post=6620"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dronebotworkshop.com\/wp-json\/wp\/v2\/tags?post=6620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}