Ardumoto problems

So I’ve got an Arduino Uno connected to a Lithium Backpack (By ground and 5V) and a fresh Ardumoto shield (By PWMA, PWMB, DIRA, DIRB, 5V and ground). The Uno is running the code from the sparkfun page for the Ardumoto (modified to use pin 3 rather than 10, of course) to try and run two connected GM9 motors.

Nothing is happening. I can verify that current is passing to the shield, that the Uno is running the code properly, and that the motors are undamaged, along with the shield and Uno themselves. I did have some fleeting success by putting 5V from the backpack through the VIN earlier whilst the Uno was connected to my laptop, but now even that doesn’t seem to function, it just feeds back into the backpack (This was before I soldered the pins of the shield onto it).

Is anyone else having a similar problem?

How many volts is your lithium battery? You keep referring to it as “5V” but that would not be a standard lithium voltage.

The Uno specifies a 7-12V input. Perhaps you could try attaching a 9V battery?

It’s the Lithium Backpack from Liquidware, it provides a regulated 5V and 3.3V charge.

Annoyingly, this is the last part of my current robotics project I need to sort out, everything else has been soldered, tested, coded, etc. This one shield is holding me up substantially.

Annoyingly, if you are using the barrel connector for input power, you need more than 5V. This is due to the linear regulator needing head room to provide a regulated voltage. Putting 5V into a linear regulator gives you something like 3.5 volts out.

One solution is to feed a regulated 5V supply into the Vin pin on the Uno or Duemilinova. This will bypass all the switching and regulators.

fll-freak:
One solution is to feed a regulated 5V supply into the Vin pin on the Uno or Duemilinova. This will bypass all the switching and regulators.

[["Vin" or "5V"](http://arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf)?

Eric](http://arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf)

“5V”. “Vin” would be equivalent to the barrel jack.

Rereading your original post it appears that you had it hooked up correctly. Sorry about the confusion I created but the term “backpack” could have meant just about anything.