The USB Proximity Trinkey, the circuit board with a Trinket M0 heart, APDS9960 Proximity, Light, RGB, and Gesture Sensor, and two RGB NeoPixels for a customizable glow. The PCB is designed to slip into any USB A port on a computer or laptop. There’s an ATSAMD21 microcontroller on board. One pin of the microcontroller connects to the two NeoPixel LEDs. Two other pins are used as capacitive touch inputs on the end and a reset button lets you enter bootloader mode if necessary.
The Trinkey has APDS9960 from Avago Technologies, which has a few different capabilities

Proximity sensingup to about 6″ away by bouncing IR light off an object

RGB color sensingcan detect color when light refects off of an object – good for bright colorful items like LEGO bricks

Ambient light sensing- how dark or bright is it in the room?

Basic gesture sensingusing 4 cardinal locations of photodiodes – this sensor is a little tough to use but it does work with practice

Configurable interrupt pin that can fire when a certain proximity threshold is broken, or when a color sensor breaks a certain threshold.