Instructables

Step 8: Wire things up to the arduino

Connect the left motor's forward transistors to pin 9, left motor backwards to pin 10, right motor's forwards to pin 11, right motor backwards pin 12. connect power from the H bridge to the 3.3v pin on the arduino, and the H bridge's ground to one of the ground pins. connect the output of the sensor to analog pin 0, the power of the QRD to the 5v pin, and the ground to one of the ground pins. We will keep these connections for all three tasks the robot will be able to perform.