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Topic: trouble shooting (Read 1 time) previous topic - next topic


I have tried to connect the arduino with the h-bridge connected to the dc motor. Using the connections defined by the program below, but its not running the dc motor.

My sketch

#define motorpin1 2
#define motorpin2 3
#define motorpin3 4
#define motorpin4 5
#define enablepin 8

void setup() {
 pinMode(motorpin1, OUTPUT);
 pinMode(motorpin2, OUTPUT);
 pinMode(motorpin3, OUTPUT);
 pinMode(motorpin4, OUTPUT);

 // set speedPin high so that motor can turn on:
 digitalWrite(enablepin, HIGH);

void loop() {
   digitalWrite(motorpin1, LOW);  
   digitalWrite(motorpin2, HIGH);  
   digitalWrite(motorpin3, LOW);  
   digitalWrite(motorpin4, HIGH);
   digitalWrite(motorpin1, LOW);  
   digitalWrite(motorpin2, LOW);  
   digitalWrite(motorpin3, LOW);  
   digitalWrite(motorpin4, LOW);


What type of H-bridge are you using?


Hi Anachrocomputer,

Am using a pololu MD03A 12 volt dc h-bridge. Am not sure of the grd connection from the h-bridge. Am sure that the hardware are okey!


Don't cross post it's not nice.


did you remember to connect Arduinos ground to the H bridge ground ?


Hi MikMo,
I have grounded the h-bridge at the arduino power pin and at the same time tappes a +5 from the arduino. Or should i ground it on the digital pin of the arduino?


Mar 27, 2009, 02:40 pm Last Edit: Mar 27, 2009, 02:41 pm by anachrocomputer Reason: 1
Connect the Ground pin of the Arduino to the Ground (or 0V) pin of the H-bridge.

You might also want to follow the advice of another poster (in the other thread) and add another 500ms delay at the end of "loop()".


I have managed to move my dc motor!! The peroblem was simply that i had missed to connect the pwm from the h-bridge to the pwm of the arduino.

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