What is a low cost, reliable method for providing a distance measurement to a CNC controller PCB that is accurate to the nearest 0.05 millimeters? The possible distances would be 0.0 to 1.0 meters. It would be for a CNC intended for wood carving. (If it were intended for metal cutting, the accuracy would need to be even better.)
The first thing I thought of was measuring the strength of a stationary magnetic field, but I doubt I could create a clean enough environment for that. Then I imagined the round trip time of a momentary light or laser blast, but I am pretty sure I can't afford anything that can be accurate to the nearest 15 picoseconds. Now I am wondering if measuring the round trip time of a momentary audio burst is feasible. It would probably need to be self-calibrating to account for changes in temperature and humidity. I don't want to freak out the dogs (or humans) in the neighborhood, so I'm thinking it would need to be a 150k+ Hertz signal. (Some animals can hear very high frequencies—although I doubt anyone nearby has a pet porpoise or beluga whale.) However, are there even low cost emitters and detectors that work for those audio frequencies? (I couldn't find any at any cost.) It's easy to build a crude emitter, but I have no idea what its capabilities or limitations would be.
Any other methods, perhaps more realistic, of measuring come to mind?
The first thing I thought of was measuring the strength of a stationary magnetic field, but I doubt I could create a clean enough environment for that. Then I imagined the round trip time of a momentary light or laser blast, but I am pretty sure I can't afford anything that can be accurate to the nearest 15 picoseconds. Now I am wondering if measuring the round trip time of a momentary audio burst is feasible. It would probably need to be self-calibrating to account for changes in temperature and humidity. I don't want to freak out the dogs (or humans) in the neighborhood, so I'm thinking it would need to be a 150k+ Hertz signal. (Some animals can hear very high frequencies—although I doubt anyone nearby has a pet porpoise or beluga whale.) However, are there even low cost emitters and detectors that work for those audio frequencies? (I couldn't find any at any cost.) It's easy to build a crude emitter, but I have no idea what its capabilities or limitations would be.
Any other methods, perhaps more realistic, of measuring come to mind?