PowerPoint presenter using a Puck.js beacon's button and magnetic sensor.

puck_pp_presenter.js

var kb = require("ble_hid_keyboard");


var next = "n";
var prev = "p";

var magIsOn = false;

var magTimeoutID = null;

// Restart BLE when Puck is powered on, and/or code is saved to flash
// And give the device a catchy name. :-)
E.on('init', function(){
  NRF.setServices(undefined, { hid : kb.report });
  NRF.setAdvertising({},{name:"Attila's PPP"});
  magIsOn = false;
  magTimeoutID = null;
});

function sendPrev(){
  sendChar(prev);
  LED2.set();
  setTimeout("LED2.reset()",1000);

  setMagTimeout();
}

// We can't query if magnetometer is on, so we
// keep track of this in magIsOn variable
function sendNext(){
  if (!magIsOn){
    Puck.magOn();
    magIsOn = true;
  }
  sendChar(next);
  LED2.set();
  setTimeout("LED2.reset()",1000);

  setMagTimeout();
}

function sendChar(chr){
  var sk = 0x02;
  if (chr == chr.toLowerCase()){
    sk = 0;
  }
  // send the keyboard character
  kb.tap(kb.KEY[chr.toUpperCase()], sk);
}

// watch the button press, action happens on button release (rising)
// debounce set to 50 to prevent unintended mechanical "bounce" triggers
setWatch(function(e) {
    sendNext(); // fire the "n" character
}, BTN, {edge:"rising", debounce:50, repeat:true});

// trigger the "p" character when the x magnetic axis value is over 0
Puck.on('mag', function(value) {
  if(value.x > 0){
    sendPrev(); // fire the "p" character
  }
});


// Turn off magnetic sensor after 30 minutes to save power.
// Each button press or magnetic gesture clears and restarts the timer.
// That way, we won't lose functionality if user is still interacting.
function setMagTimeout() {
  if (magTimeoutID){
    try{
      clearTimeout(magTimeoutID);
    } catch(err) {
      // timeout already cleared; ignore error
    }
  }

  magTimeoutID = setTimeout(function(){
    Puck.magOff();
    magIsOn = false;
  }, 1800000);
}

Changes:

• Ensure BLE is turned on when Puck is powered on or battery is replaced.
• Ensure mag turning off doesn’t happen in the middle of presenting.
• Puck.magOn() doesn’t return a boolean to check if on/off; added code to
• fix this.
• Simplified character sending code to remove duplicate code.
• Added catchy keyboard Bluetooth device name. :-)