Module development - using example of Temperature Nodes with 1-Wire PT100 / DS18B20 Sensor at multiple Locations

1. For a first step, we develop the module code and usage in single file TemperatureDevTest.js:

The code below is working and covers basically the above requirements for the module:

// TemperatureDevTest.js

// 'class' (Prototype definition)
var Temperature = function // module (class), for multiple instances
  ( name      // name hinting room / location of sensor\
  , oneWire   // one-wire; for example: new OneWire(B8);
  , addr      // address on the one-wire (required for multiples)
  , interval  // interval in milliseconds of measurements
  , preferred // optional, unit - "C" or "F" (default and not F is C)
  ) {
  // set givens
  this.name       = name;
  this.oneWire    = oneWire;
  this.addr       = addr;
  this.interval   = interval;
  this.preferred  = (preferred === "F") ? "F" : "C";
  this.enabled    = (typeof enabled === "undefined") || enabled;
  this.t = (this.preferred==="C") ? 0 : 32; // set current to 'frozen'
  this.intervalId = null; // later also used as indicator for enabled
  this.sensor     = null; // laster also used as indicatore for connected
  // get going
  this.sensor = require("DS18B20").connect(this.oneWire)­;
  this.intervalId = setInterval(function(_this) {
    _this.sensor.getTemp(function(t) {
        _this.t = t;
      });
  }, this.interval, this);
};
Temperature.prototype.getTemp = function
( unit // optional, unit "F" or "C", default "C"
) {
  var u 
      = (typeof unit === "undefined") ? this.preferred
      : (unit === "F"               ) ? "F"
      :                                 "C"
      ;
  var d = (u === "F")
      ? (this.t * 1.8 + 32) + " Fahrenheit"
      : this.t + " Celsius";
  return d;
};


// usage

// setup oneWire
var oneWire = new OneWire(B8);

// setup 1st temperature sensor ts1
var ts1 = new Temperature
  ( "office" // name / location of temperatre sensor 1
  , oneWire
  , null     // addr on one-wire currently not implemented / used
  , 5000     // every 5 secs make a read (to keep it not booring)
  , "F"      // preferred unit is Fahrenheit
  );


// for sample's sake, do everhthing deferred for more 
// than 5 seconds in order to have value(s) to display
setTimeout(function(){

// get temp in preferred and ad-hoc specified units 
console.log(ts1.getTemp());
console.log(ts1.getTemp("C"));

},6000);

The output - in the console - is as expected (code unrelated: unusually hot... a heat wave... usually it is around 50 F or even less this early in the morning...)

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 1v94 Copyright 2016 G.Williams
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83.1875 Fahrenheit
28.4375 Celsius
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