Lesson 7--Microduino “RGB LED”

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Objective By now you are familiar with using an LED. Let's take a look at the RGB LED. This new type of LED allows us to display different colors. We can also replicate the breathing light effect from last lesson. Equipment Microduino-Core Microduino-FT232R Other hardware equipment 1x Box of breadboard jumper wires 1x Breadboard 1x RGB LED 1x 220Ω resistor 1x USB Data cable RGB RGB LED contains three LEDs: red, green, and blue. By controlling the three LED's brightness, you can create any color you want. Connection Methods Method 1: Connect the longest lead wire (anode) to +5V. The other three pins are connected to a 220Ω resistor and then connected to a Microduino PWM output port. We attach resistors to prevent too much current flow from damaging the LEDs. Method 2: Connect the anode through a 220Ω resistor to +5V. The other three pins are connected to PWM output ports. Since three LEDs share a single resistor, the brightness will be dimmer. Experiment Schematic The following connection uses method 1 and uses D5,D6,D11. Program int redPin = 11; int greenPin = 5; int bluePin = 6; void setup() { pinMode(redPin, OUTPUT); pinMode(greenPin, OUTPUT); pinMode(bluePin, OUTPUT); } void loop() { setColor(255, 0, 0); // Red delay(1000); setColor(0, 255, 0); // Green delay(1000); setColor(0, 0, 255); // Blue delay(1000); setColor(255, 255, 0); // Yellow delay(1000); setColor(80, 0, 80); // Purple delay(1000); setColor(255, 255, 255);// White delay(1000); setColor(0, 0, 0); //Black delay(1000); for(int i=0;i<255;i+=5)//Red coming on { setColor(i, 0, 0); delay(30); } delay(100); for(int i=255;i>0;i-=5)//Red coming off { setColor(i, 0, 0); delay(30); } delay(100); for(int i=0;i<255;i+=5)//Blue coming on { setColor(0, i, 0); delay(30); } delay(100); for(int i=255;i>0;i-=5)//Blue coming off { setColor(0, i, 0); delay(30); } delay(100); for(int i=0;i<255;i+=5)//Green coming on { setColor(0, 0, i); delay(30); } delay(100); for(int i=255;i>0;i-=5)//Green coming off { setColor(0, 0, i); delay(30); } delay(100); } void setColor(int red, int green, int blue)//Color display program { analogWrite(redPin, 255 - red); analogWrite(greenPin, 255 - green); analogWrite(bluePin, 255 - blue); } We wrote a setColor() function so that it can be invoked in loop() directly. This makes the program look cleaner and clearer. The above program only lists a few colors you can make. You can search online for RGB values for any color you want. Result The light will go from red, green, blue, yellow, purple, black, and to white. Then, it will behave like a breathing light as in Lesson 6. Video http://v.youku.com/v_show/id_XNzEwMDA0Njg0.html