The Color Sensor

Color Sensor Types

The color sensor is used to show the paper moving in front of the distance sensor in the right color. Just like in case of the RGB LEDs different models can be found on the market. There are essentially two different types, using different sensor chips built onto a variety of breakout boards.

The GY-31 board based on the TCS2300

This board is built around the TCS34725 chip

Both chips implement color filters which let only one of the base colors pass onto a photo diode, whose intensity is then measured before switching to the next base color. The TCS2300 converts the photo diode signal into a frequency proportional to the light intensity. This board comes with 4 white LEDs to illuminate the colored object in front of it. Certain modules switch these LEDs permanently on while others (like the one shown on the photo) have a pin enabling the LEDs by software. This particular board also has a plastic ring protecting the sensor from direct light from the LEDs.

The TCS34725 does essentially the same thing but has an I2C interface in addition providing easy interfacing with a micro-controller. Here we have a single, less intense white LED, the yellow device on the photo.

-- Uli Raich - 2018-01-31

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