mute_button.ino

/*
    Heil Dual-Switch Footswitch Momentary Mute Button

    Mark Jessop < vk5qi@rfhead.net >

    Mutes system audio on Windows machine when a footswitch is pressed, then un-mutes when 
    the switch is released. This is useful when listening via a remote SDR on a PC, which
    can also hear your own transmissions (helps avoid echo!)

    Hardware:
      * Pololu A-Star 32U4 (though any other ATMega32U4 based board should work)
        * Source: https://www.littlebird.com.au/products/a-star-32u4-micro
      * Jiffy Box
      * RCA socket: Centre pin connected to Pin 0 on the A-Star, Shield connected to GND.
      * Heil FS-2 Footswitch
        * Source: https://www.strictlyham.com.au/heil-fs-2
        * NOTE: This footswitch has two outputs! One (black wire) goes to my radio, and the
          other (red wire) goes to this box.


    Extra libraries you will need to install into Arduino:
        * 'HID-Project' we use this class: https://github.com/NicoHood/HID/wiki/Consumer-API
        * Board library for whatever board you are using.
        
    Note that since switching to using the mute HID button, this acts as a toggle - so you will
    need to be sure your audio is unmuted before you press the footswitch.

*/

#include "HID-Project.h"

const int buttonPin = 0;          // Input pin connected to the switch.
int previousButtonState = HIGH;   // for checking the state of a pushButton

void setup() {
  // make the pushButton pin an input:
  pinMode(buttonPin, INPUT_PULLUP);
  // initialize control over the keyboard:
  Consumer.begin();
}

void loop() {
  // read the pushbutton:
  int buttonState = digitalRead(buttonPin);
  // if the button state has changed,
  if ((buttonState != previousButtonState)
      // and it's currently pressed:
      && (buttonState == LOW)) {
    
    // Send the 'mute' signal
    Consumer.write(MEDIA_VOLUME_MUTE);
    delay(100); // This delay acts to de-bounce

  } else if ((buttonState != previousButtonState)
      // and it's currently pressed:
      && (buttonState == HIGH)) {
    // Send the mute signal again.
    Consumer.write(MEDIA_VOLUME_MUTE);
    delay(100);
      
  }
  
  // save the current button state for comparison next loop
  previousButtonState = buttonState;
}