I’ve got a rough idea of how your device works, and I’ve found a datasheet for that motor controller (attached below), but I’m not sure how everything is connected. Could you post a photo of the internals so we can take a look at the wiring and PCB? njm2606-datasheet.pdf (187.0 KB)
In the meantime, depending on how it is wired, Liam’s guide on using an analog switch IC to emulate button presses may be helpful:
Keen to get this project on track with you!
-James
