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Torque issues and more info

A project log for Blind Motor

A motor to roll up my blinds, controlled by Home Assistant

nagupnagup 04/04/2021 at 12:000 Comments

I've done some tests, the mechanism is struggling to roll the blinds up. I will have to introduce a gearbox to the system or use a bigger stepper. The stepper being used right now is a strange one, 0 information about it, I believe it's a NEMA 15. Going to a more common NEMA 17 should give me more torque, I had these motors lying around so I thought I should use them but ill just keep them around for another project I have in mind. 

In the video, you see the whole assembly, driven by a TMC2208. I spent a couple of days troubleshooting with some A4988 drivers which turned out to be fake. The motor is extremely silent, definitely worth the extra money. The mechanism is a mix of custom 3D printed parts and parts from the original mechanism.

I think the combination of a stepper motor and a gearbox will be quite slow for my liking. I am thinking of introducing a regular DC motor for the increased RPM and then a gearbox for increased torque but that's probably going to be for the next version.

For the software side of things, I have got the HomeAssistant and esphome stuff working via a slider on the dashboard, just for testing but I want the end product to have some "limit switch" type functionality so the blinds will "home" themselves when I put the blinds all the way up in the morning, this is so that any difference between the actual position of the blinds, and where the software thinks the blind's position is will be brought back to zero, not quite sure how this will be done but I think a reed switch will do fine.

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