r/arduino • u/ikilim • Aug 19 '26

Look what I made! Upgraded my DIY Pen Plotter with a 28BYJ-48 stepper and auto-homing, but struggling with backlash. What should I improve in the next version?

https://youtu.be/I17q4qABjvM

I recently updated my 5-bar parallel linkage pen plotter by swapping the old servo for a 28BYJ-48 stepper motor and adding a limit switch for auto-homing. The drawing resolution and stability improved a lot with shorter arms, but mechanical backlash is still noticeable when changing directions.

I'm keeping this on a hobby budget:

  • Should I keep optimizing the mechanical design around the cheap 28BYJ-48 motors to fight the backlash?
  • Or is it worth biting the bullet and upgrading to NEMA 17 steppers for the next prototype?

Any mechanical tips or anti-backlash design ideas for linkage arms would be greatly appreciated!

Previous version : https://youtu.be/MOSY5ml29bg
https://youtu.be/y3IjeUqKv2A

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2

u/Zouden Alumni Mod , tinkerer Aug 19 '26

Yeah, those steppers are designed for opening vents in HVAC systems.

Upgrade to nema 17 steppers and use micro stepping if you aren't already. Nice project!!

2

u/koombot Aug 20 '26

Get a nema something.  There are smaller motors available, and pancake motors where are much thinner

2

u/mikesierrafoxtrott Aug 20 '26

The 28BYJ have internal gearing - and this is the source of the backlash.
You might be able to work around in software - but this is often unreliable. If you want to use them in some gauge or minor application, all is good. For anything robotics/mechanical - please avoid them.
Good NEMA-steppers with microstepping is the way to go.

2

u/binuuday Aug 22 '26

Get a nema man, else you will spend too much time fine tuning. Its a wrong world, that people who can tinker and create something new, are short of money.