It isn’t tough to picture a circumstance where you are stuck at home all the time with nothing to do and particular products are in brief supply. Sure, restroom tissue gets all journalism, however attempt buying some flour or a freezer and see how far you get. Plus online shopping has quit on next day shipment throughout. Not difficult to envision at all. Now expect your newest self-quarantine job requires a rotary shaft encoder. Not having one, what do you do? If you are [Tech Build] you go all MacGyver on an old printer and pull out a stepper motor. How does a stepper motor become an encoder? Well, that’s the MacGyver part. We are not huge fans of the physical circuit diagrams, but it appears like [Tech Build] obtained (with credit) from an earlier post and that one has an appropriate schematic
. Taking a look at [Andriyf1’s] schematic, you can see each coil connects to an op-amp wired as a positive feedback comparator. The result must be a relatively clean square wave from a loud input. The genuine technique is how to connect the coils, which depends upon how the stepper is wired. If you have a stepper motor of unidentified provenance, grab your ohmmeter and check out how to sort the wires out.
The initial variation was on a breadboard, however the final was on a prototyping board. Obviously, an Arduino reads the pulses. We like using things for unexpected purposes. Speakers and microphones are frequently interchangeable. Generators and motors, too. Then there’s the paperclip.