I have two 300RPM 12V DC motors connected to arduino motor shield r3 that is mounted on arduino uno board.
Problem is my motors runs very slow some times not even running.
After googling I found I need to use external power supply. I did supplied 9 volt dc power to arduino motor shield r3. But still motor is running very slow what could be the issue.
My other questions.
When supplying power to arduino motor shield r3 via external power supply pins do I need still need to provide separate power to arduino uno board via power jack.
Can I use 9 volt dc for arduino uno board and another 9 volt batter to arduino motor shield r3.
Is single 9 volt batter enough for running two 300RPM 12 dc motor.
My circuit.
My program
void setup() { //Setup Channel A pinMode(12, OUTPUT); //Initiates Motor Channel A pin pinMode(9, OUTPUT); //Initiates Brake Channel A pin //Setup Channel B pinMode(13, OUTPUT); //Initiates Motor Channel A pin pinMode(8, OUTPUT); //Initiates Brake Channel A pin } void loop(){ //Motor A forward @ full speed digitalWrite(12, HIGH); //Establishes forward direction of Channel A digitalWrite(9, LOW); //Disengage the Brake for Channel A analogWrite(3, 255); //Spins the motor on Channel A at full speed //Motor B backward @ half speed digitalWrite(13, LOW); //Establishes backward direction of Channel B digitalWrite(8, LOW); //Disengage the Brake for Channel B analogWrite(11, 123); //Spins the motor on Channel B at half speed delay(3000); digitalWrite(9, HIGH); //Engage the Brake for Channel A digitalWrite(9, HIGH); //Engage the Brake for Channel B delay(1000); //Motor A forward @ full speed digitalWrite(12, LOW); //Establishes backward direction of Channel A digitalWrite(9, LOW); //Disengage the Brake for Channel A analogWrite(3, 123); //Spins the motor on Channel A at half speed //Motor B forward @ full speed digitalWrite(13, HIGH); //Establishes forward direction of Channel B digitalWrite(8, LOW); //Disengage the Brake for Channel B analogWrite(11, 255); //Spins the motor on Channel B at full speed delay(3000); digitalWrite(9, HIGH); //Engage the Brake for Channel A digitalWrite(9, HIGH); //Engage the Brake for Channel B delay(1000); } 
