The GY-31 is a sensor that can recognize colors. In addition to the TCS3200 RGB sensor chip, there are 4 white LED lights on the sensor. These ensure that the color is clearly visible to the sensor. The TCS3200 is able to detect an (almost) unlimited number of visible colors. This sensor is ideal for sorting machines that have to sort by color, for example. The module can be directly connected to boards such as Arduino or a Raspberry Pi .