A differential modulated IR height sensor with a small form factor (small enough to mount under the heatsink of a v6 hotend). The sensor detects the target height by looking for the reflected light from two separate LEDs to be equal. The two LEDs are positioned such that they reflect light into the sensor at slightly different heights. This allows the sensor to be used on most bed surfaces. It connects to the Duet family of controllers through a dedicated probe header.
