Controlling NeoPixels

A NeoPixel is a smart RGB LED. They can be linked together into long chains or grids, and programmed easily with only 1 wire from the Arduino. It is controlled by sending an 8 bit integer for Red, Green and Blue to the Pixel. This is most easily achieved through use of the NeoPixel library you were asked to install.

The test units I provided have only a single NeoPixel. This makes them a bit less interesting since they are normally used in groups, but they can still do 24 bit color, so the exercise is still at least a little fun.

Here is a simple sketch to use it. Note that the Wheel() function isn't used in the example, but it could be useful in your own script:

#include <Adafruit_NeoPixel.h>

#define PIN 6

// Initialize a strip with a single pixel
Adafruit_NeoPixel strip = Adafruit_NeoPixel(1, PIN, NEO_GRB + NEO_KHZ800);

int lval=0;

void setup() {
  strip.begin();            // startup the strip
  strip.setPixelColor(0,strip.Color(0,64,96));   // purple
  strip.show();             // Initialize pixel to set color
}

void loop() {
delay(50);     // this isn't really necessary
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
  if(WheelPos < 85) {
   return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if(WheelPos < 170) {
   WheelPos -= 85;
   return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170;
   return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}

• First, just try loading this sketch onto the arduino as is
• Pick a different color, and make sure you can get that to work
• Finally, try having the color change over time in some way by modifying the loop() function

• When you're done, please put the BareMinimum sketch back on the Arduino

You're done. There is nothing to turn in. If there is time, and you like, you are welcome to do one of the other exercises. Otherwise you're done!