Problem with the SparkFun Monster Motor Shield

Hi,

I’m just using The Monster Motor Shield the sample code Here to drive a 12v 2a motor. If I don’t hook up the motor and run the code, i see the DIR leds switching back and forth, showing that the bridge is changing direction. When I connect my motor though, it works fine in one direction, but in the other it goes half as fast, and both leds for direction are on. One is at full brightness, and the other is at about half. Any ideas how I can fix this?

Before the Monster Motor Shield, I had it connected to an L298 driver board, and it was working fine in both directions. I switched the board because the L298 seemed to get pretty warm at the full 2A continuous.

Also, the error happens regardless of the motor I use.

Well, best I could do was to hook up the motor to both motor out pins in parallel. The shield is made to control two motors, so it looks like if you're only controlling one motor that you need to hook it up in parallel to make sure that voltage is going where you want it to. Works great now, Just have to see how it holds up.

Whoops! That's a Schroedingbug right there.

Quoting from http://cdn.sparkfun.com/datasheets/Dev/Arduino/Shields/MonsterMoto_Shield_Example.pde

pwm: should be a value between ? and 1023, higher the number, the faster
 it'll go
 */
void motorGo(uint8_t motor, uint8_t direct, uint8_t pwm)

You can't store 1023 in a uint8_t. You could never store 1023 in an 8-bit variable, not in the current version of Arduino and not in whatever version was current in 2011. And questionmark is obviously not a numeric value, so perhaps the original writer just never finished this code.

I would not try to connect both outputs of the shield together. You can get lots of smoke and flames that way.