main.js

/*jslint node:true,vars:true,bitwise:true,unparam:true */

/*jshint unused:true */

/*
The Local Temperature Node.js sample application distributed within Intel® XDK IoT Edition under the IoT with Node.js Projects project creation option showcases how to read analog data from a Grover Starter Kit Plus – IoT Intel® Edition Temperature Sensor, start a web server and communicate wirelessly using WebSockets.

MRAA - Low Level Skeleton Library for Communication on GNU/Linux platforms
Library in C/C++ to interface with Galileo & other Intel platforms, in a structured and sane API with port nanmes/numbering that match boards & with bindings to javascript & python.

Steps for installing MRAA & UPM Library on Intel IoT Platform with IoTDevKit Linux* image
Using a ssh client: 
1. echo "src maa-upm http://iotdk.intel.com/repos/1.1/intelgalactic" > /etc/opkg/intel-iotdk.conf
2. opkg update
3. opkg upgrade

Article: https://software.intel.com/en-us/html5/articles/iot-local-temperature-nodejs-and-html5-samples
*/

var B = 3975;
var mraa = require("mraa");
var coap = require('coap');

//GROVE Kit A0 Connector --> Aio(0)
var myAnalogPin = new mraa.Aio(0);

/*
Function: startSensorWatch(socket)
Parameters: socket - client communication channel
Description: Read Temperature Sensor and send temperature in degrees of Fahrenheit every 4 seconds
*/
var startSensorWatch = function() {
    'use strict';

    setInterval(function () {
	var data;
        //connect to CoAP server
        var coapWriable = coap.request('coap://192.168.0.100:8000/object/testman/send');

        var a = myAnalogPin.read();
        console.log("Analog Pin (A0) Output: " + a);
        //console.log("Checking....");
        
        var resistance = (1023 - a) * 10000 / a; //get the resistance of the sensor;
        //console.log("Resistance: "+resistance);
        var celsius_temperature = 1 / (Math.log(resistance / 10000) / B + 1 / 298.15) - 273.15;//convert to temperature via datasheet ;
        //console.log("Celsius Temperature "+celsius_temperature); 
        var fahrenheit_temperature = (celsius_temperature * (9 / 5)) + 32;

	var obj = {
	    temperature: fahrenheit_temperature
	};
	data = JSON.stringify(obj);

        console.log("Sending: " + data);

        //send to COAP broker
        coapWriable.end(new Buffer(data));
    }, 4000);
}

console.log("Sample Reading Grove Kit Temperature Sensor");

startSensorWatch();