Mood Lamp With Arduino

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Hi! In this tutorial you will learn to make a mood lamp with arduino.
I know that you may have seen a lot of mood lamp projects with arduino, but I wasn't very satisfied with them because they all change the color very abruptly. So, I decided to make a smooth mood lamp and I also made it to turn on only when the room is dark.
This project is good for those who are beginners in the arduino's world.

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Step 1: Material

For this instructable you are gonna need:
- Arduino
- Jumper wires
- 1 RGB LED or 1 red LED, 1 green LED and 1 blue LED
- LDR (Light Dependent Resistor)
- Protoboard
- Sheet of paper

Step 2: Time to Code!

Write the code above on the Arduino program.
Darker the ambient light is, the higher is the value read from the LDR.
I used PWM to change led's brightness.

// Smooth RGB mood lamp
// Changes an RGB LED's color smoothly that only turns on
// when it's dark around it.
// Author: Ricardo Ouvina
// Date: 19/07/2012
// Version: 2.0
// ---------------------------------------------------
// The brightness of the leds follows these equations:
// Red = sin(x)
// Green = sin(x + PI/3)
// Blue = sin(x + 2PI/3)
// for x from 0 to PI
// ---------------------------------------------------

float RGB;
int ldrPin = 0;     // LDR in Analog Input 0 to read the ambient light
int ambientLight;   // variable to store the value of the ambient light
int redLed   = 11;  // red LED in Digital Pin 11 (PWM)
int greenLed = 10;  // green LED in Digital Pin 10 (PWM)
int blueLed  = 9;   // blue LED in Digital Pin 9 (PWM)

void setup(){
pinMode(redLed,OUTPUT);  // tell arduino it's an output
pinMode(greenLed,OUTPUT);// tell arduino it's an output
pinMode(blueLed,OUTPUT); // tell arduino it's an output

// set all the outputs to low
digitalWrite(redLed,LOW);
digitalWrite(greenLed,LOW);
digitalWrite(blueLed,LOW);
}

void loop(){
for (float x=0;x<PI;x=x+0.00001){
RGB=255*abs(sin(x*(180/PI)));           // calculate the brightness for the red led
RGB=255*abs(sin((x+PI/3)*(180/PI)));    // calculate the brightness for the green led
RGB=255*abs(sin((x+(2*PI)/3)*(180/PI)));// calculate the brightness for the blue led
ambientLight=analogRead(ldrPin); // read an store the ambient light
if(ambientLight>600){ // start only if the ambient light is very low
//  write the brightness on the leds
analogWrite(redLed,RGB);
analogWrite(greenLed,RGB);
analogWrite(blueLed,RGB);
}
else{
digitalWrite(redLed,LOW);
digitalWrite(greenLed,LOW);
digitalWrite(blueLed,LOW);
}
for(int i=0;i<3;i++){
if(RGB[i]<1){
delay(100);
}
if(RGB[i]<5){
delay(50);
}
if(RGB[i]<10){
delay(10);
}
if(RGB[i]<100){
delay(5);
}
}
delay(1);
}
}

Step 3: Connect It!

Connect as it is on the image.

Step 4: Upload and It's Done!

Upload the code to the arduino and it's done.
Try to add a sheet of paper around it to see it more smoothly, the paper acts as a diffuser.
Feel free to modify this project to your way, and tell me your progress. Comments are welcome.
Have a look at  the video I've made. Participated in the
LED Contest with Elemental LED

9 People Made This Project!

• • • • • • • • • 65 Discussions

I made it but I'd love to know if there are any good resources out there to help me understand the code - I have learned a couple of basics but some of the terms still confuse me. Thanks for the project it's a great early confidence builder when it comes to the circuit!

Very good idea! Pls. find my modification of the code that is also smooth and shows all colors in the spectrum with higher intensity:

float RGB;
int redLed = 11; // red LED in Digital Pin 11 (PWM)
int greenLed = 10; // green LED in Digital Pin 10 (PWM)
int blueLed = 9; // blue LED in Digital Pin 9 (PWM)
int delaymood = 100; // delay for mood light

void setup(){
pinMode(redLed,OUTPUT);
pinMode(greenLed,OUTPUT);
pinMode(blueLed,OUTPUT);
digitalWrite(redLed,HIGH);
digitalWrite(greenLed,LOW);
digitalWrite(blueLed,LOW);
}

void loop(){
for (int y=0; y<=3; y++) {
if (y=1){
for (int x=0;x<=255;x++){
RGB=255-x;
RGB=0;
RGB=0+x;
analogWrite(redLed,RGB);
analogWrite(greenLed,RGB);
analogWrite(blueLed,RGB);
delay(delaymood);
}
}
if (y=2){
for (int x=0;x<=255;x++){
RGB=0;
RGB=0+x;
RGB=255-x;
analogWrite(redLed,RGB);
analogWrite(greenLed,RGB);
analogWrite(blueLed,RGB);
delay(delaymood);
}
}
if (y=3){
for (int x=0;x<=255;x++){
RGB=0+x;
RGB=255-x;
RGB=0;
analogWrite(redLed,RGB);
analogWrite(greenLed,RGB);
analogWrite(blueLed,RGB);
delay(delaymood);
}
}
}
}

--Made it in 10 minutes of opening the instructable. It was cool, but it would turn itself off with the LDR as soon as the light came on (I followed the breadboard exactally, and it was close to the LED).

So, about to move it, I took out the LDR, and it worked.... I'll just run it without it. Thank you!

Hi! thank you for the tutorial. But, i'm have a little problem here. See, i tired to combine this circuit with lm35 temperature sensor so that the circuit can sense temperature and light at the same time. I use different led for different sensor. Now the problem is, when i combine the 2 source code, the mood lamp seems not working well. It lighted up but it dont changing colors. Can you help me with this? Here is my source code:

float RGB;

float tempC;

int ldrPin = 0; // LDR in Analog Input 0 to read the ambient light

int analog_tempPin1 = 1;

int ambientLight; // variable to store the value of the ambient light

int ledPin1 = 11; // red LED in Digital Pin 11 (PWM)

int ledPin2 = 10; // green LED in Digital Pin 10 (PWM)

int ledPin3 = 9; // blue LED in Digital Pin 9 (PWM)

int ledPin4 = 7; // LED connected to digital pin 7

int ledPin5 = 6;

void setup(){

pinMode(ledPin1,OUTPUT); // tell arduino it's an output

pinMode(ledPin2,OUTPUT);// tell arduino it's an output

pinMode(ledPin3,OUTPUT); // tell arduino it's an output

// set all the outputs to low

digitalWrite(ledPin1,LOW);

digitalWrite(ledPin2,LOW);

digitalWrite(ledPin3,LOW);

pinMode(ledPin4, OUTPUT);

pinMode(ledPin5, OUTPUT);

Serial.begin(9600);

}

void loop(){

for (float x=0;x<PI;x=x+0.00001){

RGB=255*abs(sin(x*(180/PI))); // calculate the brightness for the red led

RGB=255*abs(sin((x+PI/3)*(180/PI))); // calculate the brightness for the green led

RGB=255*abs(sin((x+(2*PI)/3)*(180/PI)));// calculate the brightness for the blue led

ambientLight=analogRead(ldrPin); // read an store the ambient light

if(ambientLight>600){ // start only if the ambient light is very low

// write the brightness on the leds

analogWrite(ledPin1,RGB);

analogWrite(ledPin2,RGB);

analogWrite(ledPin3,RGB);

}

else{

digitalWrite(ledPin1,LOW);

digitalWrite(ledPin2,LOW);

digitalWrite(ledPin3,LOW);

}

for(int i=0;i<3;i++){

if(RGB[i]<1){

delay(100);

}

if(RGB[i]<5){

delay(50);

}

if(RGB[i]<10){

delay(10);

}

if(RGB[i]<100){

delay(5);

}

}

delay(1);

tempC = analogRead(analog_tempPin1); //read the value from the sensor

tempC = (5.0 * tempC * 100.0)/1024.0; //convert the analog data to temperature

Serial.print("analog ");

Serial.print(analog_tempPin1);

Serial.print(" ");

Serial.println(tempC); //send the data to the computer

if (tempC < 40){

digitalWrite(ledPin4, HIGH); // set the LED on

digitalWrite(ledPin5, LOW); // set the LED off

delay(1000); // wait for a second

digitalWrite(ledPin4, LOW); // set the LED off

digitalWrite(ledPin5, HIGH); // set the LED on

delay(1000); // wait for a second

}

if (tempC > 40){

digitalWrite(ledPin4, HIGH); // set the LED on

digitalWrite(ledPin5, LOW); // set the LED off

delay(100); // wait for 0.1second

digitalWrite(ledPin4, LOW); // set the LED off

digitalWrite(ledPin5, HIGH); // set the LED on

delay(100); // wait for 0.1second

}

}

}