Hi @jenovauh all of the CNC boards I’ve seen are built for bipolar motors, usually the much larger NEMA17 type. We’ve stuck with the micro geared steppers that we use because they’re cheap and low-power, because one of the things we care about is being able to run for a long time on batteries (e.g. in a Tanzanian clinic, where power outages are common).
There are two options:
- modify the 28BYJ-48 motors that we use to remove the “common centre tap”. This requires some dissassembly and the removal of a soldered wire. After doing this, you can drive the motors with bipolar drivers. This has some benefits (higher torque, wider selection of drivers) but we have avoided putting it in the main instructions because it’s using the motors off-spec, and it puts a lot of people off building the microscope.
- modify the microscope to use bipolar steppers. This has, I believe, been done by a team in Peru, though I’m not sure if they have shared the design yet - I should check that out! The disadvantage is that the NEMA17 motors (the most common and usually the cheapest, as they’re used in 3D printers and many other devices) are much heavier and much more power-hungry than the micro-geared motors we use at the moment.
In either case, you’d then need to replace the Python module driving our custom motor board with another one that communicates with a standard CNC board. I suspect you could use @B.Diederich’s code for this, I think he has got the server working with a GRBL board, I’m not sure if that uses the same G code as the 3D printer boards or not, but I’m pretty sure you could flash a cheap CNC board with the GRBL firmware - so you might not need to write any custom code.