Lesson 10 of 16

Drive a motor

Loading the figure…

const int MOTOR = 6; // D6 is a ~ pin, so it can do PWM void setup() { pinMode(MOTOR, OUTPUT); } void loop() { for (int s = 0; s <= 255; s += 5) { analogWrite(MOTOR, s); // 0 = stopped, 255 = full speed delay(40); } delay(1500); analogWrite(MOTOR, 0); delay(1500); }

Stopped · Your code isn't running yet. Until you press Run, the board runs the program already on it.

Nothing printed yet. Press Run.

A motor needs far more current than a pin can give. A TIP120 transistor does the heavy lifting, PWM on D6 sets the speed, and a diode catches the spike when the motor stops.

Watch it speed up, run and stop
How a small current switches a big one
Leave out the diode and the spike can kill the transistor

Pin	Connects to	What it does
`D6`	1 kΩ resistor, then the transistor's base	PWM sets the speed.
`5V`	The motor's + lead and the diode	The motor's supply.
`GND`	The transistor's emitter	The motor's current returns here.

Wire it in

Sensors and actuators this board drives, with the real connections.

TIP120 Darlington transistorSupply 5 V
Base through a 1 kΩ resistor to a PWM pin, emitter to GND, the load from 5 V (or its own supply) to the collector.
Part pin Board pin
B D6Wire colour orange
E GNDWire colour black
Careful
A motor or fan needs a 1N4007 diode across it, band toward the + supply, or switching it off sends a voltage spike into the transistor.

Part pin	Board pin
B	D6Wire colour orange
E	GNDWire colour black

All 16 parts on the Arduino Uno R3 page

Drive a motor

Try it yourself

Serial monitor

Checks

Break it

Parameters

Wire it in

Drive a motor

Try it yourself

Serial monitor

Checks

Break it

Parameters

Wire it in