TrafficLight.js

//Program: Traffic Light Simulator
//Programmer: David Evans
//Program Date: 01/15/15
//Language: Node.js

//This is the node.js version of the program, which is basically a simple traffic light... makes me wonder why traffic lights
//in reality are so damn expensive >_>. I already knew I could pull this off with Node.JS via the Cloud 9 IDE that comes with
//my beaglebone, but I just wanted something to test that everything was in running order so that the only isolated point of
//failure for my python code would be my python... not my setup. Iterative development with electronics... tasty!

var b = require('bonescript');
var green_light = "P8_13";
var yellow_light = "P8_15";
var red_light = "P8_17";

b.pinMode(green_light, 'out');
b.pinMode(yellow_light, 'out');
b.pinMode(red_light, 'out');

var time = 0;
light_color = 'none'
runLights = function(){
    time += 1
    time = time % 33
    if(time < 15 && light_color != 'green'){
        b.digitalWrite(red_light, 0);
        b.digitalWrite(yellow_light, 0);
        b.digitalWrite(green_light, 1);
        console.log('green light!');
        light_color = 'green'
    }
    else if((time >= 15) && (time <= 18) && light_color != 'yellow'){
        b.digitalWrite(green_light, 0);
        b.digitalWrite(yellow_light, 1); 
        console.log('yellow light!');
        light_color = 'yellow'
    }
    else if (time > 18 && light_color != 'red'){
        b.digitalWrite(yellow_light, 0);
        b.digitalWrite(red_light, 1);
        console.log('red light!');
        light_color = 'red'
    }
}

timer = setInterval(runLights, 1000);

stopTimer = function() {
 clearInterval(timer);
 b.digitalWrite(green_light, 0);
 b.digitalWrite(yellow_light, 0);
 b.digitalWrite(red_light, 0);
};

setTimeout(stopTimer, 450000);