Masum Ahmed

/*
  Coded by Masum Ahmed www.mahmed.tech for NodeJs <---> Arduino Communication Project
  Date: 12/07/2017
  Version: 1.00
*/
//-------------------------- Program ------------------------------
// include the various libraries that you'll use:
var myPort = require('serialport');  // include the serialport library
var mysql = require('mysql');		// include the mysql library
var ledBrightness = '0';
var newValue = true;
var portOpen = false;

// ------ SQL Databse Details -----------------
  var con = mysql.createConnection({
  host: "Server IP",
  user: "Your_Username",
  password: "Your_Passowrd",
  database : "Database_Name"
});
//---------------------------------------------

//----------- Make SQL Connection -------------
con.connect(function(err, result) {
  if (err) throw err;
  console.log("Connected to SQL Database");
});
//---------------------------------------------

//Communication speed must match arduino setting. 
// Serial port configuration:
	//SerialPort = serialport.SerialPort,             // make a local instance of serialport
    portName = process.argv[2],                 // get serial port name from the command line
    delimiter = 'n';                // serial parser to use, from command line
var serialOptions = {                           // serial communication options
      baudRate: 9600,                           // data rate: 9600 bits per second
      parser: delimiter // newline generates a data event
    };

// if the delimiter is n, use readline as the parser:
if (delimiter === 'n' ) {
  serialOptions.parser = myPort.parsers.readline('\n');
}

if (typeof delimiter === 'undefined') {
  serialOptions.parser = null;
}

// If the user didn't give a serial port name, exit the program:
if (typeof portName === "undefined") {
  console.log("You need to specify the serial port, like so:\n");
  console.log("    node myscript.js portname");
  process.exit(1);
}

//---------- New Serial Port Instance ---------
var myPort = new myPort(portName, serialOptions);
//---------------------------------------------


// set up event listeners for the serial events:
myPort.on('open', showPortOpen);
myPort.on('data', sendSerialData);
myPort.on('close', showPortClose);
myPort.on('error', showError);


function readSQL(data){
	con.query(data, function (err, result) {
		if (err) throw err;
		console.log(result.affectedRows + " record(s) updated");
  });
}

function writeSQL(data){
	con.query(data, function (err, result, fields) {
    if (err) throw err;
    //console.log(result[0].LedPWM);
	if(ledBrightness != result[0].LedPWM){
		ledBrightness = result[0].LedPWM.toString();
		newValue = true;
		console.log("New Brightness: "+ledBrightness);
	}
  });
}

// this is called when the serial port is opened:
function showPortOpen() {
  console.log('port open. Data rate: ' + myPort.options.baudRate);
  //portOpen = true;
}

// this is called when new data comes into the serial port:
function sendSerialData(data) {
  writeQuery("UPDATE ArduinoJS SET Value = '"+data+"' WHERE ID = 1");
  console.log("PotValue: "+ Number(data));
}

function showPortClose() {
   console.log('port closed.');
}
// this is called when the serial port has an error:
function showError(error) {
  console.log('Serial port error: ' + error);
}

//This function is called to write data to serial port
function sendToSerial(data) {
  myPort.write(data);
}

//Makes a update (write) query to the sql table
function writeQuery(querya){
	con.query(querya, function (err, result) {
		if (err) throw err;
		console.log(result.affectedRows + " record(s) updated");
  });
}

//makes a select query on a sql table
function readQuery(queryb){
	con.query(queryb, function (err, result, fields) {
    if (err) throw err;
    //console.log("SQL LED PWM Value: "+result[0].LedPWM);  //for debugging
	//will only write to serial if the value changes from the previous stored brightness aka user has inputed new pwm value
	if(ledBrightness != result[0].LedPWM){  
		console.log("\n  Old Brightness: "+ledBrightness+"\n  New Brightness: "+result[0].LedPWM.toString()+"\n");
		//The results is in a Array hence this notation this can be seen printing the results directly 
		ledBrightness = result[0].LedPWM.toString();
		sendToSerial(ledBrightness);
	}
  });
}
//-------------------------------------------- Main Loop ------------------------
function mainLoop(){
	readQuery("SELECT LedPWM FROM ArduinoJS WHERE ID = 1");  //selects pwm value 
}

setInterval(mainLoop, 5000);  // Will call mainLoop every 5 Seconds (default)