Just like we did in the previous circuit, copy and paste the code into a new Arduino sketch. Then compile and upload it to your metro.
/* -----------------------------------------------------------
* | Arduino Experimentation Kit Example Code |
* | CIRC-03 .: Spin Motor Spin :. (Transistor and Motor) |
* -----------------------------------------------------------
*
* The Arduinos pins are great for driving LEDs however if you hook
* up something that requires more power you will quickly break them.
* To control bigger items we need the help of a transistor.
* Here we will use a transistor to control a small toy motor
*
*
*/
int motorPin = 9; // define the pin the motor is connected to
// (if you use pin 9,10,11 or 3you can also control speed)
/*
* setup() - this function runs once when you turn your Arduino on
* We set the motors pin to be an output (turning the pin high (+5v) or low (ground) (-))
* rather than an input (checking whether a pin is high or low)
*/
void setup()
{
pinMode(motorPin, OUTPUT);
}
/*
* loop() - this function will start after setup finishes and then repeat
* we call a function called motorOnThenOff()
*/
void loop() // run over and over again
{
motorOnThenOff();
//motorOnThenOffWithSpeed();
//motorAcceleration();
}
/*
* motorOnThenOff() - turns motor on then off
* (notice this code is identical to the code we used for
* the blinking LED)
*/
void motorOnThenOff(){
int onTime = 2500; //the number of milliseconds for the motor to turn on for
int offTime = 1000; //the number of milliseconds for the motor to turn off for
digitalWrite(motorPin, HIGH); // turns the motor On
delay(onTime); // waits for onTime milliseconds
digitalWrite(motorPin, LOW); // turns the motor Off
delay(offTime); // waits for offTime milliseconds
}
/*
* motorOnThenOffWithSpeed() - turns motor on then off but uses speed values as well
* (notice this code is identical to the code we used for
* the blinking LED)
*/
void motorOnThenOffWithSpeed(){
int onSpeed = 200; // a number between 0 (stopped) and 255 (full speed)
int onTime = 2500; //the number of milliseconds for the motor to turn on for
int offSpeed = 50; // a number between 0 (stopped) and 255 (full speed)
int offTime = 1000; //the number of milliseconds for the motor to turn off for
analogWrite(motorPin, onSpeed); // turns the motor On
delay(onTime); // waits for onTime milliseconds
analogWrite(motorPin, offSpeed); // turns the motor Off
delay(offTime); // waits for offTime milliseconds
}
/*
* motorAcceleration() - accelerates the motor to full speed then
* back down to zero
*/
void motorAcceleration(){
int delayTime = 50; //milliseconds between each speed step
//Accelerates the motor
for(int i = 0; i < 256; i++){ //goes through each speed from 0 to 255
analogWrite(motorPin, i); //sets the new speed
delay(delayTime); // waits for delayTime milliseconds
}
//Decelerates the motor
for(int i = 255; i >= 0; i--){ //goes through each speed from 255 to 0
analogWrite(motorPin, i); //sets the new speed
delay(delayTime); // waits for delayTime milliseconds
}
}
Motor Not Spinning?
If you sourced your own transistor, double check with the data sheet that the pinout is compatible with a PN2222 (many are reversed).
Check Your Motor
If you sourced your own motor, double check that it will work with 5 volts and that it does not draw too much power.
Still having issues?
Sometimes the Metro board will disconnect from the computer. Try un-plugging and then re-plugging it into your USB port.
Tried the steps above? Still didn't resolve your issue?
Page last edited January 22, 2025
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