Ardumoto not working

Hello,

I have an Ardumoto motor driver shield plugged into a Freetronics Eleven Uno compatible.

I've hooked it all up, downloaded a sample sketch (modified because I only have one motor), applied 9V to Vin, and the yellow and blue leds on the Ardumoto light up which seems to indicate the sketch is running, but the motor does not run. Power direct to the motor runs ok. The single motor is attached to the "A" connector.

Any idea what the problem could be ?

Sketch is below

//=========================================
// Motor Control using Ardumoto Shield
//=========================================

int pwm_a = 3; //PWM control for motor outputs 1 and 2 is on digital pin 3
int pwm_b = 11; //PWM control for motor outputs 3 and 4 is on digital pin 11 - Second motor if attached
int dir_a = 12; //dir control for motor outputs 1 and 2 is on digital pin 12
int dir_b = 13; //dir control for motor outputs 3 and 4 is on digital pin 13 - second motor if attached

void setup()
{
pinMode(pwm_a, OUTPUT); //Set control pins to be outputs
// pinMode(pwm_b, OUTPUT);
pinMode(dir_a, OUTPUT);
// pinMode(dir_b, OUTPUT);

analogWrite(pwm_a, 100);
// set both motors to run at (100/255 = 39)% duty cycle (slow)
// analogWrite(pwm_b, 100);

}

void loop()
{
digitalWrite(dir_a, LOW); //Set motor direction, 1 low, 2 high
// digitalWrite(dir_b, LOW); //Set motor direction, 3 high, 4 low

delay(1000);

analogWrite(pwm_a, 255);
//set both motors to run at 100% duty cycle (fast)
// analogWrite(pwm_b, 255);

delay(1000);

digitalWrite(dir_a, HIGH); //Reverse motor direction, 1 high, 2 low
// digitalWrite(dir_b, HIGH); //Reverse motor direction, 3 low, 4 high

delay(1000);

analogWrite(pwm_a, 100);
// set both motors to run at (100/255 = 39)% duty cycle
// analogWrite(pwm_b, 100);

delay(1000);
}

Can you measure the voltage coming from the motor output terminals on the shield? If so, what voltage is there?

Voltage at output point ? SFA would be about it. 16 V at Vin on the Ardumoto

hsteve:
Voltage at output point ? SFA would be about it. 16 V at Vin on the Ardumoto

Double-check your shield’s header pin soldering for shorts, and also reduce the Vin to <12V. Max Vin for an Eleven is 12V:

There appeared to be a short across the power output terminals. Once I removed them the thing worked.

Thanks

Does the 9v power supply have sufficient current capability to power a motor?

Does the 9v power supply have sufficient current capability to power a motor?

Both the power supply and the motor came from an RC car, so they were designed to work together