{"id":6842,"date":"2020-01-19T16:41:59","date_gmt":"2020-01-19T21:41:59","guid":{"rendered":"https:\/\/dronebotworkshop.com\/?p=6842"},"modified":"2023-04-12T11:04:53","modified_gmt":"2023-04-12T15:04:53","slug":"arduino-color-sense","status":"publish","type":"post","link":"https:\/\/dronebotworkshop.com\/arduino-color-sense\/","title":{"rendered":"Color Sensing with Arduino"},"content":{"rendered":"\n

\"Download \"Parts<\/a> \"View<\/a> \"Download<\/a><\/p>\n

Today we will look at two different types of color sensors that you can use with an Arduino or other microcontrollers. One of these is an inexpensive device that has been available for years, the other sensor offers improved performance and an I2C interface.<\/span><\/p>\n

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Introduction<\/span><\/h2>\n

Color sensing is often used in industrial and manufacturing applications for quality control, but there are several other uses for this technology.\u00a0 Color sensors can be used to build sorting machines, for photographic and lighting applications and even to build a device to solve a Rubik’s Cube!<\/span><\/p>\n

Your local hardware store likely uses a color sensor to match samples to blend paint.<\/span><\/p>\n

\"Color<\/p>\n

While there are some very expensive color sensors used in industrial applications there are also very inexpensive ones used for less stringent applications. We will use a couple of these sensors today with an Arduino.<\/span><\/p>\n

One of the sensors we are using is a very popular one, the TCS230 (also TCS3200). This sensor is available at Amazon, eBay and probably at your local electronics shop. It is quite inexpensive and pretty easy to use.<\/span><\/p>\n

The second sensor is a module from Sparkfun, based upon the Intersil ISL29125 sensor chip. This sensor communicates using the I2C bus, making hookup very easy.<\/span><\/p>\n

We will see how to hookup and calibrate both sensors, and then how to use them to get RGB values.\u00a0<\/span><\/p>\n

Color Sensing Principles<\/span><\/h2>\n

There are a variety of different color sensors, each having specific advantages and disadvantages. Most of them work on the same basic principles.<\/span><\/p>\n

Before we add a sensor to our Arduino project it would be a good idea to take a look at how some of these sensors work.<\/span><\/p>\n

How Color Sensors Work<\/span><\/h3>\n

Most color sensors are comprised of an array of light sensors, usually photodiodes or phototransistors.\u00a0<\/span><\/p>\n

\"Color<\/p>\n

The light sensors are filtered so that they only accept one of the primary colors red, green or blue. There is also an unfiltered sensor to gauge the relative light level in most sensors.<\/span><\/p>\n

The sensors are addressed one color at a time, and the light intensity is measured. As there are an array of sensors the results are averaged, and then sent out for processing.\u00a0 By measuring the relative level of red, green and blue, the color of the object detected by the sensor can be determined.<\/span><\/p>\n

These devices are far from perfect, and as photodiodes and phototransistors do not respond to every wavelength of light equally the results are not linear between the three colors. These nonlinearities are compensated for in the processing device, which in our case would be an Arduino.<\/span><\/p>\n

In most applications, it isn\u2019t actually important that the results are nonlinear, or that the output is not true RGB values. Just knowing the readings for the color you are trying to detect is often enough.<\/span><\/p>\n

Color Sensor Types<\/span><\/h3>\n

While most color sensors consist of an array of color-filtered light sensors their output methods can differ.<\/span><\/p>\n