As I’ve already discussed here and here, opto detectors are one way to sense position. Unlike a switch, there’s no moving parts, so reliability is high. However, the compromise is a more complicated setup. In a previous article, I showed a schematic that sent a signal to the Arduino when the light beam was unbroken between diode and sensor, and turned off when it was broken. One reader commented that the usual way was the reverse, and included a link … Continue reading →