How to Make an Arduino Powered Mood Lamp

Introduction: How to Make an Arduino Powered Mood Lamp

About: Creation Crate is a hands-on learning platform for 21st-century skills! We help makers learn programming, engineering, circuits, wearable tech, and more. All courses are authenticated by Go to…

A Mood Lamp is a great beginner Arduino project!

This "Mood Lamp" project will show you how to create a lamp that changes colors when it's dark.

This just so happens to be a project from our Electronics curriculum but you can still create this project without being a member of Creation Crate!

Step 1: Hardware

The Parts You Will Need:

Light Dependent Resistor (LDR) X1


Green LED X 1

Blue LED X 1

Regular Jumper Wires X 8

U-Shaped Jumper Wires X 6

2.2k OHM Resistor X 1

Breadboard X 1

UNO R3 (Arduino Compatible) X 1

USB Cable X 1

Paper Lanter X 1


How to find these parts:

1. Google your way through life

2. Roll the dice with Amazon parts

3. Buy reliable parts from our Maker Shop


Receive every single part you need (with extra) in one crate with Creation Crate!

Step 2: LED and LDR

Step 3: Connect the Jumper Wires

Attach the U-shaped wires to the 6 locations shown.

Step 4: Connect the Uno Microcontroller

Attach the rest of the (8) wires as shown.

Step 5: Place the Lantern Over the LEDs

Step 6: Programming

1. Let's start by going to

2. Download the Arduino Software (IDE).

3. Open the Arduino program and navigate to 'File > New'.

4. Delete all of the existing text/code. (Note: the program is made up of lines of code)

5. Navigate to 'File > Save' and save the program as "Mood Lamp".

6. Click next and start programming!

When you join Creation Crate, you receive access to an entire Online Classroom that breaks down each part of the code and teaches it to you step by step.

For time's sake, we will upload the entire code for you here.


/* Creation Crate Mood Lamp

This lamp smoothly cycles through a color spectrum. It only turns on when its surroundings are dark. Color equations (we’ll be using these later): Red = sin(x) Green = sin(x + PI/3) Blue = sin(x + 2PI/3) These equations are how the program will calculate the brightness of the LEDs.*/

// Step 1: Input User Defined Variables Think of variables like containers - they’re used to store information.

int pulseSpeed = 5; // This value controls how fast the mood lamp runs. You can replace this with any whole number.

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

int redLed = 11; // red LED in Digital Pin 11.

int greenLed = 10; // green LED in Digital Pin 10.

int blueLed = 9; // blue LED in DIgital Pin 9. // These are the pins we are using with the UNO R3 (Arduino-compatible). You can see the numbers on the board itself.

int ambientLight; // This variable stores the value of the light in the room.

int power = 150; // This variable controls the brightness of the lamp (2-255).

float RGB[3]; // This is an ‘array’. It can hold 3 values: RGB[0], RGB[1], and RGB[2].We’ll use this to store the values of the Red, Blue, and Green LEDs.

float CommonMathVariable = 180/PI;

/* Step 2: Create Setup Loop This ‘loop’ is not really a loop. It runs once in the beginning to create the default values for our LEDs. */

void setup () {

Serial.begin(9600); // Starts the serial monitor, which can be used for troubleshooting.

// This tells the UNO R3 to send data out to the LEDs.

pinMode (redLed,OUTPUT);

pinMode (greenLed,OUTPUT);

pinMode (blueLed,OUTPUT);

// This sets all the outputs (LEDs) to low (as in off), so that they do not turn on during startup.

digitalWrite (redLed,LOW);

digitalWrite (greenLed,LOW);

digitalWrite (blueLed,LOW);

} // Opening brackets must be accompanied by closing brackets.

/* Step 3: Create Main Loop The previous sections are where we set up the variables. This section is where we put them to work! This part of the program is a ‘loop’. It repeats itself over and over again, making a small change in the brightness of the LEDs each time - this creates a smooth transition in colour. */

void loop () {

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

RGB[0] = power * abs(sin(x * (CommonMathVariable))); // Red LED.

RGB[1] = power * abs(sin((x + PI/3) * (CommonMathVariable))); // Green LED.

RGB[2] = power * abs(sin((x + (2 * PI) / 3) * (CommonMathVariable))); // Blue LED.

ambientLight = analogRead(ldrPin); // This reads the light in the room and stores it as a number. Serial.println(ambientLight); // Prints the value to the serial monitor for troubleshooting

// This ‘if statement’ will make the lamp turn on only if it is dark. The darker it is, the higher the number.

if (ambientLight > 100) {

// These ‘analogWrite’ statements will send the values calculated above to the LEDs.

analogWrite (redLed,RGB[0]);

analogWrite (greenLed,RGB[1]);

analogWrite (blueLed,RGB[2]);

} // Don’t forget to close this ‘if statement’ with a bracket!

else {

// This ‘else statement’ will only activate if the ‘if statement’ above does not (ie. If it is too bright in the room). The LEDs will turn off.

digitalWrite (redLed,LOW);

digitalWrite (greenLed,LOW);

digitalWrite (blueLed,LOW); }

// This loop calculates the delay for each colour depending on its current brightness. Brighter LEDs will change colour slower and vice versa.

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

if (RGB[i] < 1) { delay (20 * pulseSpeed);


// ’else if’ means only one of these conditions can activate at a time.

else if (RGB[i] < 5) { delay (10 * pulseSpeed); }

else if (RGB[i] < 10) { delay (2 * pulseSpeed); }

else if (RGB[i] < 100) { delay (1 * pulseSpeed); }

else {} // This blank ‘else statement’ is a fail-safe mechanism. It instructs the program to do nothing if the conditions above do not activate. This prevents the program from generating errors when calculating delays.





Step 7: More Learning Resources

Join Creation Crate And Learn How To Build Electronic Projects Like A ...

  • Bluetooth Boombox
  • Line Following Roverbot
  • Weather Station
  • Alarm Clock


More Maker Resources

Subscribe To Our Youtube Channel

Receive Weekly Maker Emails With Project Ideas And Videos


Blogs You Might Enjoy

The Ultimate Arduino Tutorial

7 Arduino Projects For Beginners

Best Resources For Learning Electronics

Be the First to Share


    • For the Home Contest

      For the Home Contest
    • Big and Small Contest

      Big and Small Contest
    • Make It Bridge

      Make It Bridge



    4 years ago

    Thanks! Glad to see you appreciate the projects. You are right about the Young makers and we see it applying to old makers as well. About half our user base is made up of older makers to be exact. Great to see that learning has no age limit!


    4 years ago

    Nice work! It's great to see options like this for getting young makers on the right track! : )