LEDs

I STARTED WORKING PLAYING with my Netduino a few days ago. Since I was just getting started (and I don’t have any motors or anything anyway), I tried something simple. Lighting up and changing the color of an RGB LED. The initial program technically worked, but it didn’t really work well. The color changes were often abrupt, and the algorithm I was using to cycle through colors led to the LED going dark quite often, sometimes for several seconds at a time. One iteration of the software even had multi-minute LED blackouts. The only reason I realized the LED hadn’t just shut off altogether was that it came back on while I was studying the code.

Anyway, this project isn’t really anything to brag about, and I likely wouldn’t post about it at all, except that it’s the first program that I really feel does what I want it to. Also, I created a class for the RGB LED that made changing the colors a little easier, and I’m pretty pleased with that one, so I’d like to share it.

using System;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace ColorChangingLED
{
    using System;
    using Microsoft.SPOT.Hardware;

    class Program
    {

        public class rgbLED
        {
            public rgbLED(Cpu.Pin RedOut, Cpu.Pin GreenOut, Cpu.Pin BlueOut)
		    {
			    // The Pins are all set by the constructor.
			    //  Red, Green, and Blue uints CAN be set here, but
			    //  otherwise will default to zero.
			    this.redPin = new PWM(RedOut);
			    this.greenPin = new PWM(GreenOut);
                this.bluePin = new PWM(BlueOut);
			    this.redPin.SetDutyCycle(this.Red);
			    this.greenPin.SetDutyCycle(this.Green);
			    this.bluePin.SetDutyCycle(this.Blue);

		    }

            // These will be used to set the duty cycles of the individual pins,
            //  governing the color output on the LED.
            public uint Red = 0;
            public uint Green = 0;
            public uint Blue = 0;

            // Specific individual pins...
            private PWM redPin;
            private PWM greenPin;
            private PWM bluePin;

            public void HSV(double hue, double saturation, double value)
            {
                // Convert HSV to RGB and set LED appropriately.

                // This method doesn't really do anything at this point.
                //  It will, though...
                // Formulas to convert HSV to RGB will go here.  

                // Then set the led to display the new color.
                // Set the uints Red, Blue, and Green.
                //this.Red = ;
                //this.Green = ;
                //this.Blue = ;

                // Set the uints Red, Blue, and Green.
                this.redPin.SetDutyCycle(this.Red);
                this.greenPin.SetDutyCycle(this.Green);
                this.bluePin.SetDutyCycle(this.Blue);

            }

            public void RGB(uint r, uint g, uint b)
            {
                // Set the uints Red, Blue, and Green.
                // Then set the led to display the new color.

                this.Red = r;
                this.Green = g;
                this.Blue = b;
                this.redPin.SetDutyCycle(this.Red);
                this.greenPin.SetDutyCycle(this.Green);
                this.bluePin.SetDutyCycle(this.Blue);
            }
        }

        static void Main()
        {
		    // Initialize our LED (NOTE: on the Netduino, 5, 6, 9, and 10 are the only PWM pins)
            rgbLED RGB1 = new rgbLED(Pins.GPIO_PIN_D5,Pins.GPIO_PIN_D6,Pins.GPIO_PIN_D9);

		    // Declare our color values (doubles are used instead of uints to add some variation)
		    double red, green, blue;

		    // Declare the "bandwidth" variables that will decide how much change each color gets.
		    double redBW, greenBW, blueBW;

		    // Initialize a random.  We'll use that shortly.
		    Random rand = new Random();

            // Set initial values.
		    red = 10.0;
		    blue = 10.0;
		    green = 10.0;
		    redBW = 0.5;
		    blueBW = 2.1;
		    greenBW = 4.8;

		    for (int i = 0; i < 1000; i++)
 		    { 			    // Step each of our color values up (or down, if the BW value is negative)
 			    red += redBW;
 			    blue += blueBW;
 			    green += greenBW;
			    if (red > 100.0) // If our value is out of range, reset.
				{
                                    red = 100.0;
                                    redBW = -1.0*((double)rand.Next(50)) / 40;
                                }
                            if (red < 0.0)
                                {
                                    red = 0.0;
                                    redBW = ((double)rand.Next(50)) / 40;
                                }
			    if (green > 100.0) // If our value is out of range, reset.
				{
                                    green = 100.0;
                                    greenBW = -1.0*((double)rand.Next(50)) / 40;
                                }
                            if (green < 0.0)
                                {
                                    green = 0.0;
                                    greenBW = ((double)rand.Next(50)) / 40;
                                }
			    if (blue > 100.0) // If our value is out of range, reset.
				{
                                    blue = 100.0;
                                    blueBW = -1.0*((double)rand.Next(50)) / 40;
                                }
                            if (blue < 0.0)
                                {
                                    blue = 0.0;
                                    blueBW = ((double)rand.Next(50)) / 40;
                                }

			    RGB1.RGB((uint)red,(uint)blue,(uint)green);
			    Thread.Sleep(100);
		    }

            RGB1.RGB(0, 0, 0);
            Thread.Sleep(Timeout.Infinite);
        }
    }
}