I have a major issue with two days until competition. I have two small motors that I am using… One that controls the arm to swing from left to right and another for the arm to extend in and out. For the longest time (2 weeks) both motors have been working. Well, now one will work and one will not. Yesterday the in and out was working and not spinning… Today it is the spinning one working and not the in and out… I have my helpers check the voltage of the motors and wires. Nothing wrong with them. I have checked and double checked my easy c program and can see nothing wrong. Any ideas of what might have happen?

Thank you in advance,
NL Robotics

Thanks for mentioning BEST, and for (also) posting in the community supported forum where many people can offer suggestions.

  • Since you are asking for help, we can’t much trust your data (“nothing wrong” with code or wires) because you don’t have any details.

This is a good opportunity to demonstrate the scientific method: create a testable falsifiable hypothesis and try to disprove it.

Hypothesis1: its your code.

  • If you post the code, we can look at it. Not otherwise.

Hypothesis2: its the #29 motor controllers, or loose wires.

  • if you control the motors forward and backward, and they don’t move, put a voltmeter on the motor terminals; Do you see corresponding positive and negative voltages?
  • for all the related white plastic connector blocks: unscrew, inspect, retighten
  • double check all plug to plug connections, reinforce with no-residue painters tape
  • make sure someone didn’t swap the motor controllers between days

Hypothesis3: the ptc current limiters are overheating and shutting off half the power.

  • Do both motors work from a cold start?
  • describe all your motor/servo uses and what ports they are plugged into.

Hypothesis4: you used the wrong screws or motor mount metal thickness on both small motors, and bent the internal gear plates; now both work intermittantly, maybe only in one direction away from jam, or for some small distance.

  • describe your motor mount system and screw length
  • do motors turn by hand with no binding? any grinding sounds?

Other debugging ideas:

  • Test each motor port in isolation: Unplug all the motor ports, then plug in 1 motor at a time and test it, then unplug it again. After all work independently, try adding one at a time.

I figured it out. It was my external motor control 29… I don’t know how it went out or what went wrong, but I changed that up and IT WORKS!!!Jgraber, thank you for the ideas and now I know what to look for.