This circuit is designed to control a motor using an Arduino UNO microcontroller. The motor's speed is regulated through Pulse Width Modulation (PWM) on one of the Arduino's digital pins. A MOSFET is used as a switch to control the high-power circuit of the motor. A resistor is connected between the MOSFET gate and ground to ensure the MOSFET turns off when not driven by the Arduino. A diode is used to protect against voltage spikes caused by the inductive load of the motor, and a tantalum capacitor is added to smooth out any voltage fluctuations. The circuit is powered by a 12V battery.
/*
* This Arduino sketch controls a motor using a MOSFET. The motor speed is
* controlled via PWM on digital pin 9. A 10k ohm resistor is connected
* between the gate pin and ground to ensure the MOSFET turns off when the
* pin is low. A diode and capacitor are used to protect against voltage
* spikes.
*/
const int motorPin = 9;
void setup() {
pinMode(motorPin, OUTPUT);
}
void loop() {
// Set the PWM frequency to 500 Hz
analogWriteFrequency(motorPin, 500);
// Set the PWM duty cycle to 50% (adjust this to control speed)
analogWrite(motorPin, 128);
// You can change the duty cycle in a loop to vary the speed
// For example:
for (int dutyCycle = 0; dutyCycle <= 255; dutyCycle++) {
analogWrite(motorPin, dutyCycle);
delay(10);
}
}
The code sets up the Arduino to output a PWM signal on pin D9, which controls the MOSFET gate and thus the motor speed. The PWM frequency is set to 500 Hz, and the duty cycle starts at 50%. The loop then gradually increases the duty cycle from 0% to 100%, varying the motor speed accordingly.