sensor-slave.js

gistfile1.txt

var plotly = require('plotly')('streaming-demos','3yyglqsi85');
var five = require("johnny-five");
var board = new five.Board();
var EventEmitter = require('events').EventEmitter;

// lets do this
board.on("ready", function () {

  var photoresistor = new five.Sensor({ pin: "A0", freq: 50, threshold: 100 });
  var potentiometer = new five.Sensor({ pin: "A5", freq: 50, threshold: 100 });

  var sinner = SinBox();
  console.log('ready');
  var stream = plotly.stream('xtndiqvpol', function (err, res) {
    if (err) console.log(err);
    console.log(res);
  });

  potentiometer.scale([ 0, 4000 ]).on("data", function () {
    var freq = this.value/1000;
    sinner.setFrequency(freq);
  });

  photoresistor.scale([ 0, 1 ]).on("data", function () {
    sinner.setAmplitude(this.value);
  });

  sinner.on('data', function (data) {
      //console.log(data);
      stream.write(JSON.stringify(data)+'\n');
  });
});

// little helper function to get a nicely formatted date string
function getDateString () {
  var time = new Date();
  var datestr = new Date(time - 14400000).toISOString().replace(/T/, ' ').replace(/Z/, '');
  return datestr;
}

function SinBox () {
    var self = new EventEmitter();

    self.freq = 0; // should be between 200ms and 4 seconds?
    self.amp = 0;  // should be between 0 and 1

    self.start = Date.now();
    self.switcher = 0;

    self.setAmplitude = function (amp) {
        self.amp = amp;
        self.switcher = !self.switcher;
        if (self.switcher)
            self.computeSignal();
    };

    self.setFrequency = function (freq) {
        self.freq = freq;
        self.switcher = !self.switcher;
        if (self.switcher)
            self.computeSignal();
    };

    self.computeSignal = function () {
        var now = Date.now();
        var ts = (now - self.start) / 1000;
        var x = new Date(now - 14400000).toISOString().replace(/T/, ' ').replace(/Z/, '');
        var y = self.amp * Math.sin(self.freq * ts);


        self.emit('data', {x:x, y:y} );
    };

    return self;

}