Code snippets for Bluetooth Low Energy Raspberry Pi presentation at Maker Faire NY 2015

00_characteristic.js

var TemperatureCharacteristic = function() {
    TemperatureCharacteristic.super_.call(this, {
      uuid: 'bbb1',
      properties: ['read', 'notify'],
    });
};
util.inherits(TemperatureCharacteristic, Characteristic);

01_onSubscribe.js

TemperatureCharacteristic.prototype.onSubscribe 
              = function(maxValueSize, updateValueCallback) {
  this.changeInterval = setInterval(function() {
    sensor.temperature(sensorId, function(err, result) {
        if (result != lastTemp) {
          lastTemp = result;
          var data = new Buffer(4);
          data.writeFloatLE(result, 0);
          updateValueCallback(data);
        }
    });
  }.bind(this), 2000);
}

02_onUnsubscribe.js

TemperatureCharacteristic.prototype.onUnsubscribe = function() {
  console.log('TemperatureCharacteristic unsubscribe');

  if (this.changeInterval) {
    clearInterval(this.changeInterval);
    this.changeInterval = null;
  }
};