BitSwitch for Intel Edison sample using Node.js

bitswitch_intel_edison_main.js

/*jslint node:true, vars:true, bitwise:true, unparam:true */
/*jshint unused:false */
/*global */

var mraa = require('mraa'); //require mraa
var request = require('request');
var _ = require('underscore')

var addr2watch = '19e2eU15xKbM9pyDwjFsBJFaSeKoDxp8YT' // bitcoin address to watch 
//var loop_time  = 10000 // ms (check every 10 sec)
var loop_time  = 3000  // ms   (check every 3 sec)
var balance    = null
var relayPin   = new mraa.Gpio(13)

var check_balance = function(){
  // this version uses blockchain.info direct api - but I could've used blockr.io, chain.com or the awesome bitcore-explorers library
  request('https://blockchain.info/q/addressbalance/'+addr2watch, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      var satoshi = parseInt(body)
      var btc = satoshi*Math.pow(10, -8)
      
      // this is the simplest approach, just check if the balance if different
      // you could check if the price is increased by X amount or better if you got a transaction exactly of x btc
      if (balance && balance != btc)
        activate()

      balance = btc
    }
    _.delay(check_balance, loop_time)
  })
}

var activate = function() {
  console.log("Address balance changed, new one is:", balance, "BTC")
  console.log("Let there be light!")
  relayPin.write(0); 
}

var main = function() {
  console.log('MRAA Version: ' + mraa.getVersion()); //write the mraa version to the Intel XDK console
  relayPin.dir(mraa.DIR_OUT);
  relayPin.write(1); 
  
  console.log("check_balance() initialized")
  check_balance()
}


main()