I am making an elevator controlled by a raspberry pi zero and driven by a stepper motor. I have managed to get the engine working using a python script and an MPC28017 pin expander (i2c protocol).

This is the script: https://gist.github.com/aitormendez/7797a6bc52e6f20c27abcad241225c9a

The script working: https://youtu.be/tuPRvOaolGY

And this is the elevator:

Elevator enter image description here

So far everything has gone well, but I have been stuck in the planning and construction of the mechanical part coupled to the engine and I need help and advice on it.

There are two problems to solve. The first is what and how it is attached to the motor shaft. The motor shaft (5mm diameter) does not have a gear attached and I cannot find one on the market with a 5mm hole. What options are there? How is it usually done?

The second problem is that the motor, although it seems quite accurate, turns very slowly so I will need more gears with the same tooth size to build a throttle.

In short, what elements are necessary to be able to transmit the force of the motor to a pulley.

Thank you so much.

  • 3
    Not Pi specific. The 28BYJ-48 stepper will max out at 17 RPM and has surprisingly little torque (the 12V version is better). I would get another stepper. Re fixing to shaft look up shaft couplers. This is the wrong site for the question. he project is interesting. Have you asked on raspberrypi.org/forums ?
    – joan
    Nov 19 '20 at 18:47
  • Ah, ok. I will try there. Thanks.
    – aitor
    Nov 19 '20 at 18:50
  • 1
    @aitor, Welcome and nice to meet you. Your programs, video, and GitHub stuff are impressive. I look forward to see you elevator ascending! :) BTW, you might be interested to read the catalog of motor shaft copulers: aliexpress.com/w/wholesale-shaft-coupler.html. /to continue ...
    – tlfong01
    Nov 20 '20 at 2:22
  • 1
    I recommend newbies to start with something like this: fr.aliexpress.com/item/…. / to continue, ...
    – tlfong01
    Nov 20 '20 at 2:25
  • 1
    And you might also need to consider high torques stepping motors: aliexpress.com/popular/stepper-motor-high-torque.html. /to continue, ...
    – tlfong01
    Nov 20 '20 at 2:28

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