Description: A 1N4004 Rectifer Diode (a.k.a flyback diode, snubber diode, kickback diode) is used to prevent back EMF from a fan motor connected to an Arduino Nano.
Notes: The grey band represents the negative side. A forward voltage drop of around .7V can be expected for the 1N4004 diode. A back EMF (reverse voltage spike) gets created when the magnetic field of a coil (like in a motor) collapses. Therefore, in order to avoid damage to electrical components, a rectifier diode which only let’s voltage flow in one direction and not in the other is used to protect from reverse voltage spikes.
Supplies:
1 – Breadboard 400 Points
1 – Arduino Nano
1 – Metal Push-Button 12mm >> Link <<
1 – 1N4004 Rectifier Diode >> Link <<
1 – 10k Resistor
1 – 5V Brushless DC Fan >> Link <<
Arduino Code:
#define fan 6
#define button 16
int fanState = LOW;
int lastSwitchVal = LOW;
void setup() {
pinMode(fan, OUTPUT);
pinMode(button, OUTPUT);
}
void loop() {
int switchVal = digitalRead(button);
if (switchVal != lastSwitchVal && switchVal == HIGH) {
fanState = !fanState;
}
digitalWrite(fan, fanState);
lastSwitchVal = switchVal;
}