12 September 2020

Turn a relay on and off using a push button. When using a pushbutton, you have use a library (don't reinvent the wheel) to control the push button signal. It's called a debounce, taking account in faulty signals and long button holds, still resulting in a single click. In this sample code I use acebutton library, you can find it from "Tools -> Manage Libraries..." in your Arduino code editor.

MEGA2560 - https://s.click.aliexpress.com/e/_dSHcI3D
Solderless Prototype Breadboard - https://s.click.aliexpress.com/e/_dZBtgob
Push Buttons - https://s.click.aliexpress.com/e/_dWLsiIR
Relay - https://s.click.aliexpress.com/e/_dYUsVFl
Jumper Wires - https://s.click.aliexpress.com/e/_d81TuyF

 
Source code viewer
#include <AceButton.h>
using namespace ace_button;
 
#define RELAY_ON LOW
#define RELAY_OFF HIGH
 
const int BUTTON_PIN = 2;
const int RELAY_PIN = 3;
 
AceButton button(BUTTON_PIN);
 
void handleEvent(AceButton*, uint8_t, uint8_t);
 
void setup() {
  // Relay setup.
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, RELAY_OFF);
 
  // Button setup.
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  button.setEventHandler(handleEvent);
}
 
void loop() {
  button.check();
}
 
void handleEvent(AceButton* /*button*/, uint8_t eventType, uint8_t /*buttonState*/) {
  switch (eventType) {
    case AceButton::kEventPressed:
      if (digitalRead(RELAY_PIN) == RELAY_ON) {
        digitalWrite(RELAY_PIN, RELAY_OFF);
      }
      else {
        digitalWrite(RELAY_PIN, RELAY_ON);
      }
      break;
  }
}
arduino relay button