Stepper motor driven smart blinds

Hello!

I'm using a TMC2208 - Nema 17 combo to raise and lower blinds. I'm powering the system with a 24v PSU, and while the blinds are quite wide, the setup is able to raise them 90% of the time.

I was wondering if increasing the PSU voltage to 36v (max for the TMC2208) would yield more torque? I've decrease the step speed dramatically and it has helped a lot, but I want them to work reliable 99% of the time.

If the blinds fail to roll up even once, that will cause a calibration/indexing issue that will be unfixable until re-calibrated.

Switching to a larger NEMA-17 isn't an option because the space between the wall and the window is only a few inches, so a larger-bodied motor will not fit.

Raising the supply voltage will increase the torque.

Have you set the coil current limit on the driver to the motor max? Are you using microstepping?

What is the max coil current of the motor? Post a data sheet.

Just curious how you are re-calibrating. Might be worth considering some type of limit/home switch. Maybe a hall effect sensor would work.

This appears to be a very common problem…
Developers put stepper motors in applications that really aren’t ideal for them.

A blind controller is screaming out for an h-bridge, DC motor and reduction gear.

Limit switches would be ideal, or use timed run, and a slip clutch at the extents

1 Like