The concept behind this circuit design is that you can press buttons without touching them. As your finger lowers to the tabletop, the yellow light will come on, indicating that you are on the correct approach. Farther down, the green light comes on, which activates the button function.
Or so it’s supposed to work. What I find is that when my finger is on the lower level, the upper sensor will still detect its position, which is bad enough, but since it’s measuring at a diagonal, it will measure the distance as greater than it is.
Possible solutions would be to redesign the circuit so that there is a UDS pointing up from each button position. But that would require four sensors rather than two even for this circuit.
Hmm, I wonder how big the ‘spray pattern’ is for the sensor pings. If it’s fairly wide, then the position of the finger could be determined by triangulation.
Available on Amazon: