Let's Make Arduino LED Holiday Lighting

3. Let’s light up!

Now, let’s create a program to light up the LED string. The sample code below is based on

Adafruit_NeoPixel code example.

Sample program of LED strip

#include <Adafruit_NeoPixel.h>
 
#define PIN 6   	//pin number of the signal terminal
#define LED_NUM 50  //number of LEDs
 
Adafruit_NeoPixel ledtape = Adafruit_NeoPixel(LED_NUM, PIN, NEO_GRB + NEO_KHZ800);  //if the control IC of the LED tape used is WS2812, the third parameter is NEO_KHZ800 and if WS2811 then NEO_KHZ400
 
void setup() {
  ledtape.begin();
  ledtape.show();   //reflects once in all OFF state
}
 
void loop() {
 uint16_t i, j;
 
 for(j=0; j <256; j++) {
   for(i=0; i < ledtape.numPixels(); i++) {
     ledtape.setPixelColor(i, rotateColor((((i) * 256 / ledtape.numPixels()) + j) & 255));
   }
   ledtape.show();
   delay(20);
 }
}
 
//RGB color transition function
uint32_t rotateColor(byte WheelPos) {
  if(WheelPos < 85) {
   return ledtape.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if(WheelPos < 170) {
   WheelPos -= 85;
   return ledtape.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170;
   return ledtape.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}

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#include <Adafruit_NeoPixel.h>

#define PIN 6 //pin number of the signal terminal

#define LED_NUM 50 //number of LEDs

Adafruit_NeoPixel ledtape = Adafruit_NeoPixel(LED_NUM, PIN, NEO_GRB + NEO_KHZ800); //if the control IC of the LED tape used is WS2812, the third parameter is NEO_KHZ800 and if WS2811 then NEO_KHZ400

void setup() {

ledtape.begin();

ledtape.show(); //reflects once in all OFF state

}

void loop() {

uint16_t i, j;

for(j=0; j <256; j++) {

for(i=0; i < ledtape.numPixels(); i++) {

ledtape.setPixelColor(i, rotateColor((((i) * 256 / ledtape.numPixels()) + j) & 255));

}

ledtape.show();

delay(20);

}

//RGB color transition function

uint32_t rotateColor(byte WheelPos) {

if(WheelPos < 85) {

return ledtape.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

} else if(WheelPos < 170) {

WheelPos -= 85;

return ledtape.Color(255 - WheelPos * 3, 0, WheelPos * 3);

} else {

WheelPos -= 170;

return ledtape.Color(0, WheelPos * 3, 255 - WheelPos * 3);

}

If the LED tape is connected and the program runs correctly, you will see the LEDs lighting up.

Figure 7. LED tape lighting

Also, if you change the program a little bit, it’s also possible to light the LEDs one after another, one by one.

Program to light the LEDs one at a time

#include <Adafruit_NeoPixel.h>
 
#define PIN 6   	//pin number of the signal terminal
#define LED_NUM 50  //number of LEDs
 
Adafruit_NeoPixel ledtape = Adafruit_NeoPixel(LED_NUM, PIN, NEO_GRB + NEO_KHZ800);  //if the control IC of the LED tape used is WS2812, the third parameter is NEO_KHZ800 and if WS2811 then NEO_KHZ400
 
void setup() {
  ledtape.begin();
  ledtape.show();   //reflects once in all OFF state
}
 
void loop() {
  uint16_t i, j;
 
//Set the state of all colors of the LED in minutes and light in show
 for(i=0; i < ledtape.numPixels(); i++) {
   ledtape.setPixelColor(i, Wheel((((i) * 256 / ledtape.numPixels()) + j) & 255));
   ledtape.show();
   ledtape.setPixelColor(i, ledtape.Color(0,0,0));
   delay(20);
   ledtape.show();
 }
}
 
//RGB color transition function
uint32_t rotateColor(byte WheelPos) {
  if(WheelPos < 85) {
   return ledtape.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if(WheelPos < 170) {
   WheelPos -= 85;
   return ledtape.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
   WheelPos -= 170;
   return ledtape.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}

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#include <Adafruit_NeoPixel.h>

#define PIN 6 //pin number of the signal terminal

#define LED_NUM 50 //number of LEDs

Adafruit_NeoPixel ledtape = Adafruit_NeoPixel(LED_NUM, PIN, NEO_GRB + NEO_KHZ800); //if the control IC of the LED tape used is WS2812, the third parameter is NEO_KHZ800 and if WS2811 then NEO_KHZ400

void setup() {

ledtape.begin();

ledtape.show(); //reflects once in all OFF state

}

void loop() {

uint16_t i, j;

//Set the state of all colors of the LED in minutes and light in show

for(i=0; i < ledtape.numPixels(); i++) {

ledtape.setPixelColor(i, Wheel((((i) * 256 / ledtape.numPixels()) + j) & 255));

ledtape.show();

ledtape.setPixelColor(i, ledtape.Color(0,0,0));

delay(20);

ledtape.show();

}

//RGB color transition function

uint32_t rotateColor(byte WheelPos) {

if(WheelPos < 85) {

return ledtape.Color(WheelPos * 3, 255 - WheelPos * 3, 0);

} else if(WheelPos < 170) {

WheelPos -= 85;

return ledtape.Color(255 - WheelPos * 3, 0, WheelPos * 3);

} else {

WheelPos -= 170;

return ledtape.Color(0, WheelPos * 3, 255 - WheelPos * 3);

}

You can decorate your indoor or outdoor spaces using the LED string we just programmed. (Even though Halloween has just passed) when set up with jack-o’-lantern, you feel it’s Halloween all over again!

Today, we learned the basics of how to use LED strip/string Next time, we will be using a sensor from ROHM Sensor Evaluation Kit to create a device that manipulates LED string based on the sensor input values. The holidays will be here before you know it! Add some holiday spirit to your home using these cool LED strip/string projects!