Micro dual motor controller


I’ve recently bought a micro dual motor controller with the two motors Tamiya Gearbox. I’m using it with a basic stamp II. The problem is tha sometimes the motor controller doesn’t respond to the commands (shutdown, start at intervals, etc).

I think that the proble is caused by the termal shut down of the controller. What can I do?.

Im using 4 AA batteries as power source for the motors.

Will a heatsink solve the problem, or maybe the controller is damaged.

I thought that that dual gearbox was perfect for the controller , but maybe the voltage is too high.

I tried using only two AA batteries but the motors wasn’t strong enough to drive my robot.




The motors are 3 V motors, so running them off of 6 V will definitely cause the motors to draw too much current for the micro motor controller. The twin-motor gearbox is suitable for small robots like our 5-inch round chassis, and if your motors can’t move your robot at 3 V, you might want to go with larger motors. They will run at 6 V, but you will wear them out sooner.

If you want to run at 6 V, you might also consider running just one motor per motor controller (configured for single-motor mode) and see if it still overheats. Even at 3 V, though, the motor stall current is well beyond the limit of the micro motor controller, so before you do anything else, you should probably measure the current your motors are drawing to see what your requirements are.

In general, a heat sink will help, and it won’t hurt to try. You just might be so far beyond the limit of the motor controller that it won’t be enough.

- Jan

Hi Jan:

Thank you for the answer. I’m thinking that a couple of capacitors between the leads of the motors could help, lowering the max current draw of them.

Also maybe the capacitor may help if I’m using 3v as power source providing the extra current for the motors in the change of direction, start, etc

I’m not sure about the capacitors, please tell me if that could help using both configurations (3v and 6v).

thank you!!!


The capacitors won’t work the way you are planning on using them. All of the power that goes to your motor has to go through the motor controller, and you are trying to use more than what the motor controller can deliver. There is also no point in artificially reducing the current draw of the motor: you can already do that, by lowering the supply voltage. If that does not give you enough power, then anything else you do to reduce the current won’t give you enough, either.

In general, it’s good to put a small capacitor across the motor for noise reduction. However, that capacitor does not help supply current when you need to change the motor direction; rather, it opposes the change because it also needs to get “turned around” in the sense that it needs to get discharged and then charged in the opposite direction.

Large capacitors on your motor supply can help the power supply during small bursts of increased current consumption. However, this increased current still has to go through the motor controller, and that is what is limiting you. Also, sources such as NiCd or NiMh battery packs don’t typically need any large capacitors across them.

- Jan

I think, I will try with three aa batteries (4,5 v) as power source to deliver a little more tha 3v to the motors. Also I will attach a heatsink to the controller to reduce the temperature of it.

Also I’m thinking of adding more pauses to my program to reduce the current draw in the transitions.

tahnk you!!