How to Build Color Combination LED system using LDR

What if we can use a solitary RGB LED to make distinct colors and make our area corners much more desirable? So this is a very simple Arduino-dependent shade mixing light that alterations shade when the room’s mild alterations. Thus, this light-weight will quickly change colour in accordance to the lighting disorders of the home.

How to Build Color Combination LED system using LDR

Every single shade is a combination of purple, environmentally friendly and blue. Consequently, we can create any colour by working with red, environmentally friendly and blue. So right here we will change the PWM, the light intensity on the LDR. This will further more adjust the intensity of pink, inexperienced and blue in the RGB LED and will generate distinct colors.

The desk below displays the shade mixtures for each and every responsibility cycle alter.

Components Specifications


We will use a photoresistor (or photoresistor, LDR or photoconductive cell) in this circuit. The LDR is designed of a semiconductor materials to give it a photosensitive residence. The working principle of these LDR or Photograph RESISTORS is “photoconductivity”. The basic principle now states that whenever the gentle falls on the floor of the LDR (in this situation), the conductance of the ingredient boosts, or in other words and phrases, when the light falls on the surface area of the LDR, the resistance of the LDR decreases. Because the LDR is a attribute of a semiconductor material employed on the surface area, this sort of a characteristic that the resistance of the LDR is decreased is reached.

There are 3 LDR sensors for managing the brightness of the crimson, inexperienced and blue LEDs inside the RGB Led. Find out a lot more about employing the Arduino to handle LDR listed here.

How to Build Color Combination LED system using LDRRGB LED:

There are two forms of RGB LEDs, one is popular cathode sort (frequent cathode form), and the other is widespread anode style (common anode sort). In CC (prevalent cathode or widespread cathode), there will be 3 favourable terminals, every terminal symbolizing a person color and one particular damaging terminal symbolizing all a few colors.

  • RGB LED common anode lead wire
  • Typical anode RGB LED

How to Build Color Combination LED system using LDR

In our circuit we will use the CA (popular anode or popular anode) kind. In the Prevalent Anode variety, if we want the Purple LED to turn on, we need to have to floor the Crimson LED pin and electrical power the widespread beneficial. This is genuine for all LEDs. Discover to interface RGB LEDs with Arduino here.

 Circuit schematic:

How to Build Color Combination LED system using LDR

Arduino shade mixing lamp employs RGB and LDR circuit diagram

The comprehensive circuit diagram for this project is as described over. The +5V and floor connections proven in the circuit diagram are out there from the 5V and floor pins of the Arduino. The Arduino alone can be powered by a laptop or a DC jack employing a 12V adapter or 9V battery.

Build Color Combination LED system using LDR

Upload Resource Code

const byte crimson_sensor_pin = A0

const byte eco-friendly_sensor_pin = A1

const byte blue_sensor_pin = A2

const byte environmentally friendly_led_pin = 9

const byte blue_led_pin = 10

const byte crimson_led_pin = 11

unsigned int red_led_value      =

unsigned int blue_led_value     =

unsigned int environmentally friendly_led_value    =

unsigned int red_sensor_value   =

unsigned int blue_sensor_value  =

unsigned int eco-friendly_sensor_benefit =

void setup()





void loop()

red_sensor_price = analogRead(red_sensor_pin)

hold off(50)

blue_sensor_price = analogRead(blue_sensor_pin)

hold off(50)

green_sensor_benefit = analogRead(environmentally friendly_sensor_pin)

// print these values on to the serial check

Serial.println(“Raw Sensor Values:”)

Serial.print(“t Purple: “)


Serial.print(“t Blue: “)


Serial.print(“t Green: “)

Serial.println(environmentally friendly_sensor_value)

// convert from -1023 to -255

purple_led_value   = purple_sensor_worth / 4   // outline Crimson LED

blue_led_value  = blue_sensor_benefit / 4  // determine Blue LED

eco-friendly_led_worth = environmentally friendly_sensor_worth / 4 // determine Eco-friendly LEd

// print mapped values to serial keep an eye on

Serial.println(“Mapped Sensor Values:”)

Serial.print(“t Red: “)


Serial.print(“t Blue: “)


Serial.print(“t Inexperienced: “)


// use analogWrite() to established output for RGB LED

analogWrite(crimson_led_pin,red_led_worth)   // indicate purple LED

analogWrite(blue_led_pin,blue_led_worth)  // suggest blue LED

analogWrite(green_led_pin,inexperienced_led_worth) // indicate environmentally friendly

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