Arduino/DC Motors/PWM with transistor

First Sketch

We use a variable resistor to change the duty cycle.

The motor is powered by any DC source.

The middle pin on the transistor is the control pin.

The left(flat/labeled/non-Heatsink) side is the ground.

The right pin is the voltage return to ground.

You power the motor from the positive side of the battery.

The potentiometer simply

#define pwm 3  // Use pin 3 for the pwm output.

#define pot A0 // the resistor will go on analog input pin 0

void setup()   // put your setup code here, to run once:

{

  pinMode(pwm,OUTPUT);  // Define pin pwm as an output.

  pinMode(pot,INPUT);  // Define pin pot as an input.

  Serial.begin(9600);  // Start the serial monitor.

  analogWrite(pwm,0);    // Make sure the motor is off.

}

void loop()  // This is the main code that runs till power off.

{

  float val = analogRead(pot);

  float duty = map(val,0,1023,0,255) // Change the input range of 1023 to the output range of 255

  analogWrite(pwm,duty);  // Set pin pwm to duty value.

  Serial.print("PWM = ");

  Serial.print(pwm);  // Print the pwm value.

  Serial.print("  ");

  Serial.println(duty); // Print the Duty value and then do a carriage return.

}