Beat IoT device. Start, pause, and stop music playing iPhone with a PuckJS.

playerHID.js

/*
Custom Beat IoT device. Start, pause, and stop music playing iPhone with a PuckJS.

This source code is an alternative to BLE HID. BLE HID is great and offers devices 
a Bluetooth integration that lets a device simulate media, keyboard, mouse buttons.
Unfortunately, iPhones do not support BLE HID at the system level that is required, 
but your macOS laptop or android device can. More on BLE HID here -
https://learn.sparkfun.com/tutorials/bluetooth-basics/bluetooth-profiles
 
This device intends to operate as a faux BLE HID through "Diny" [an iOS app].
 
Load JS source code on device here https://www.espruino.com/ide/
https://www.puck-js.com/
*/

NRF.setServices({
    0x180F : [Puck.getBatteryPercentage()], // Set battery level
    0xBCDE : { // Set button state 0 play-pause, 1 play-pause, 2 stop
        0xABCD : {
            value : [0],
            readable : true,
            notify: true,
            indicate : true,
            broadcast : true
        }
    }
},{ advertise: [ 'BCDE' ] });

var playFlag = true; // Redundancy - app play-pause will return 0 or 1 in addition to a BLE notify alert. If you don't trust the BLE alert, check if play-pause changed from 0 to 1.

setWatch(function(e) {
     var len = e.time - e.lastTime;
     if (len > 0.4) {
         // advertise stop-restart
         advertise(2);
         digitalPulse(LED1,1,100);
     } else {
         // advertise play-pause
         advertise(playFlag >>> 0);
         playFlag =! playFlag;
         digitalPulse(LED2,1,100);
     }
}, BTN, { edge:"falling",repeat:true,debounce:50});

function advertise(State){
    print(State);
    NRF.updateServices({
        0xBCDE : {
            0xABCD : {
                value : [State],
                notify: true
            }
        }
    });
}