Arduino with SMC05a

Hi there,

I am still new to physical computing but I am advanced in programming (hope so Wink ), so here is a question for the specialists in electronics, I think.

I have an Arduino Duemilanove with:

  • 9V Batterie or USB-Power-suppy
  • two Tamiya motors with a 4,5 V power supply
  • a Pololu smc05a dual motorcontroller


  • (+) of the 4,5 V power supply to pin 1
  • pin2 to Arduino GND and power supply (-) /GND
  • pin3 5V from Arduino (measured, exactly 5 V)
  • pin 4 to Arduino pin 7 (Arduino software serial OUT)
  • pin 5 to Arduino pin 87 (reset)
  • pin 6,7 to Motor 0
  • pin 8,9 to Motor 1

My question is: What is wrong, because absolutly nothing happens on pin 6-9.
I used the code here:


It looks like you’re connecting things correctly. Are your LEDs doing anything?

- Jan

No, the LEDs do nothing. I think the controller is simply broken.
Thanks for reply

Did anything ever happen (e.g. reverse polarity application; overheating, smoke coming out) that would support the notion that the motor controller is just broken? While these kinds of things can be destroyed easily if used the wrong way, many of the items we get back for repair actually work just fine. It sounds like you might be ready to give up, but if you don’t know of anything bad having happened to the unit, you could contact us to get an RMA number and send it back for us to check out.

- Jan