TRACE unit is mainly consist of 4 sets of IR, 1x infrared emitting and 1x infrared receiver for each set. The infrared LEDs should be placed towards and close to the ground where having black tracing lines and white background (or vice versa) layouts.
The IR transmitter keep emitting, at the mean time infrared ray would be absorbed by different color of objects. Black can absorb more ray than other color, so the infrared receiver (infrared sensitive phototransistor) would receive less which makes the resistance value of the phototransistor would vary with different object color. Then we assign an AD convertor tp capture the data.
This Unit communicates with the M5Core via GROVE PORTA I2C (0x5A).
I purchase this product to build a line follower with a Beetle. I had somme difficulties to program it in UIFlow/Blockly because of the I2C (the M5StickC detect the Beetle and display an error message about the I2C)