This Electronic Edge Finder detects touchdown using either a cutter or a rod mounted in the spindle of a mill or the chuck of a lathe. Unlike my last design, this one is all analog, no Arduino.
It is a simple circuit using seven resistors, two capacitors, one dual opamp, a diode, two LEDs, and two pushbuttons. Power is from a USB wall wart or battery pack. If you replace one of the LEDs with an opto, the circuit is compatible with CNC systems.
Click here if you are interested.
Your comments are welcome. All of us are smarter than any one of us.