Build A Color Changing LED Tree Using Arduino

You will need:

1x ATtiny85
10x male header pins
Solid core wire, 2 colors
A bunch of LEDs

1x Arduino Uno to program the ATtiny

To prep the Arduino for programming the ATtiny, follow the guide on this page.

After you have done that, upload this sketch to the ATtiny.

//CODE STARTS HERE

//ATtiny85 RGB color fading tree

const int 2Pin = 2;
const int 1Pin = 1;
const int 0Pin = 0;

void setup()
{
pinMode(2Pin, OUTPUT);
pinMode(1Pin, OUTPUT);
pinMode(0Pin, OUTPUT);

}

void loop() {
2to21();
21to1();
1to10();
10to0();
0to02();
02to2();
}

void 2to21()
{
digitalWrite(redPin, HIGH);
digitalWrite(bluPin, LOW);

// fade up green
for(byte i=1; i<100; i++) {
byte on  = i;
byte off = 100-on;
for( byte a=0; a<100; a++ ) {
digitalWrite(grnPin, HIGH);
delayMicroseconds(on);
digitalWrite(grnPin, LOW);
delayMicroseconds(off);
}
}
}

void 21to1()
{
digitalWrite(grnPin, HIGH);
digitalWrite(bluPin, LOW);

// fade down red
for(byte i=1; i<100; i++) {
byte on  = 100-i;
byte off = i;
for( byte a=0; a<100; a++ ) {
digitalWrite(redPin, HIGH);
delayMicroseconds(on);
digitalWrite(redPin, LOW);
delayMicroseconds(off);
}
}
}

void 1to10()
{
digitalWrite(grnPin, HIGH);
digitalWrite(redPin, LOW);

// fade up blue
for(byte i=1; i<100; i++) {
byte on  = i;
byte off = 100-on;
for( byte a=0; a<100; a++ ) {
digitalWrite(bluPin, HIGH);
delayMicroseconds(on);
digitalWrite(bluPin, LOW);
delayMicroseconds(off);
}
}
}

void 10to0()
{
digitalWrite(bluPin, HIGH);
digitalWrite(redPin, LOW);

// fade down green
for(byte i=1; i<100; i++) {
byte on  = 100-i;
byte off = i;
for( byte a=0; a<100; a++ ) {
digitalWrite(grnPin, HIGH);
delayMicroseconds(on);
digitalWrite(grnPin, LOW);
delayMicroseconds(off);
}
}
}

void 0to02()
{
digitalWrite(bluPin, HIGH);
digitalWrite(grnPin, LOW);

// fade up red
for(byte i=1; i<100; i++) {
byte on  = i;
byte off = 100-on;
for( byte a=0; a<100; a++ ) {
digitalWrite(redPin, HIGH);
delayMicroseconds(on);
digitalWrite(redPin, LOW);
delayMicroseconds(off);
}
}
}

void 02to2()
{
digitalWrite(redPin, HIGH);
digitalWrite(grnPin, LOW);

// fade down blue
for(byte i=1; i<100; i++) {
byte on  = 100-i;
byte off = i;
for( byte a=0; a<100; a++ ) {
digitalWrite(bluPin, HIGH);
delayMicroseconds(on);
digitalWrite(bluPin, LOW);
delayMicroseconds(off);
}
}
}

//CODE ENDS HERE