What is RGB led??
RGB led are a combination of red, green, and blue in one
package used to produce millions of different varieties of colors. As we know
RED, BLUE, and GREEN are primary colors, by mixing these three colors at different
intensities we can achieve our desired color.
By using primary color (ADDITIVE COLOR) we can obtain
secondary color
RED + GREEN = YELLOW
RED + BLUE = MAGENTA
BLUE + GREEN = CYAN
RED + BLUE + GREEN = WHITE
Similarly, when using
secondary color (SUBTRACTIVE COLOR) we can obtain secondary color
MAGENTA + YELLOW = RED
MAGENTA + CYAN = BLUE
CYAN + YELLOW = GREEN
MAGENTA + YELLOW + CYAN = BLACK
For example – if we want red, then we will keep the pin of red led to high intensity and the other two pins to low intensity. If we want yellow then we will adjust the light intensity of red and green pins to the appropriate proportion to produce yellow color as yellow color is a combination of red and green color.
We commonly use a common cathode configuration, which means all negative pins should have common ground while changing positive voltage at the desired proportion of each LED pin to get various different shades of color patterns. Here to achieve different combinations of color we use the analog write function, the problem with digital write is that we can only give 0v to 5v means HIGH or LOW. So we use analog Write to mix different primary colors (red, green, blue) and create new thousands of color combinations.
Parts Required
- KY-016 (RGB sensor module)
- Arduino
- Jumper wires
Schematic Diagram
Basic code for RGB led with Arduino
Code -
int RED_LED=3; // set red pin of led to pin 3
int Green_LED=5; // set green pin of led to pin 5
int Blue_LED=6; // set blue pin of led to pin 6
void setup() {
pinMode(RED_LED,OUTPUT); // declare red pin of led as output
pinMode(Green_LED,OUTPUT); // declare green pin of led as output
pinMode(Blue_LED,OUTPUT); // declare blue pin of led as output
}
void loop() {
red(); // calling red led function
delay(300); // delay of 300 millisecond
green(); // calling green led function
delay(300);
blue(); // calling blue led function
delay(300);
}
void red() // creating function to glow red light
{
digitalWrite(RED_LED,HIGH); // red light turn on
digitalWrite(Green_LED,LOW); // green light turn off
digitalWrite(Blue_LED,LOW); // blue light turn off
}
void green() // creating function to glow green light
{
digitalWrite(RED_LED,LOW); // red light turn off
digitalWrite(Green_LED,HIGH); // green light turn on
digitalWrite(Blue_LED,LOW); // blue light turn off
}
void blue() // creating function to glow blue light
{
digitalWrite(RED_LED,LOW); // red light turn off
digitalWrite(Green_LED,LOW); // green light turn off
digitalWrite(Blue_LED,HIGH); // blue light turn on
}
First initialize pins of RGB led module Connect ground pin of RGB to ground pin of Arduino, VCC pin to 5v and red pin to 3, green pin to 5, blue pin to 6. We will declare led pins as OUTPUT. Also, we configure the baud rate to 115200.
In the red function, we have written code to only turn on the red led pin keeping the other two pins green and blue led off. Similarly in green () and blue (). We have written code to turn green and blue led on.
Controlling RGB led using user input in serial monitor??
In this, we are using input from users to change the color of the RGB
led. First, we have to print the text “choose the color”. Here we have used the while
loop to see if the user has entered any text. If the user has put no input at serial monitoring
then while loop is not broken until there is an input from the user.
We will get the value entered by the user using Serial.read() function and store it in variable name color. Here
we are using the switch case conditions to compare the conditions with user input. If the user enters ‘r’ then the red light will glow, if the user enters ‘g’ then the green light
will glow, light glowing, if the user enters ‘b’ then the blue light will glow, if the user
enters ‘m’ then magenta light will glow, if the user enters ‘y’ then yellow light
will glow, if the user enters ‘c’ then cyan light will glow, if the user enters ‘w’
then white light will glow.
Code -
int Green_LED=5; // set green pin of led to pin 5
int Blue_LED=6; // set blue pin of led to pin 6
char color;
void setup()
{
pinMode(RED_LED,OUTPUT); // declare red pin of led as output
pinMode(Green_LED,OUTPUT); // declare green pin of led as output
pinMode(Blue_LED,OUTPUT); // declare blue pin of led as output
Serial.begin(115200); // set a baud rate of 115200
}
void loop()
{
Serial.println("Choose the color"); // print the message
while(Serial.available()==0) // while loop will not break until there is user input
{
}
color = Serial.read(); // Read values from user input and store it in variable
//Serial.print(color);
switch (color) { // using switch case condition to check user input
case 'r': // if user presses r then led will emit red color
analogWrite(RED_LED,255);
analogWrite(Green_LED,0);
analogWrite(Blue_LED,0);
Serial.println("red");
break; // breaks the condition if satisfies
case 'g': // if the user presses g then led will emit green color
analogWrite(RED_LED,0);
analogWrite(Green_LED,255);
analogWrite(Blue_LED,0);
Serial.println("green");
break;
case 'b': // if the user presses b then led will emit blue color
analogWrite(RED_LED,0);
analogWrite(Green_LED,0);
analogWrite(Blue_LED,255);
Serial.println("blue");
break;
case 'w': // if the user presses w then led will emit white color
analogWrite(RED_LED,255);
analogWrite(Green_LED,255);
analogWrite(Blue_LED,255);
Serial.println("White");
break;
case 'y': // if the user presses y then led will emit yellow color
analogWrite(RED_LED,240);
analogWrite(Green_LED,200);
analogWrite(Blue_LED,0);
Serial.println("yellow");
break;
case 'm': //, if user presses m then led, will emit a magenta color
analogWrite(RED_LED,240);
analogWrite(Green_LED,0);
analogWrite(Blue_LED,200);
Serial.println("magenta");
break;
case 'c': // if the user presses c then led will emit a cyan color
analogWrite(RED_LED,0);
analogWrite(Green_LED,240);
analogWrite(Blue_LED,200);
Serial.println("cyan");
break;
default: // by default all Led will be turned off
analogWrite(RED_LED,0);
analogWrite(Green_LED,0);
analogWrite(Blue_LED,0);
}
delay(2000); // delay of 2 sec
}
Output -
Controlling RGB led using 3 push buttons for different colors??
First initialize pins of RGB led module Connect ground pin of RGB to ground pin of Arduino, VCC pin to 5v and red pin to 3, green pin to 5, blue pin to 6. We have set the red button pin to 8, we have set the green button pin to 9, and we have set the blue button pin to 10. We have also declared variables for reading push button values.
int Green_LED=5; // set green pin of led to pin 5
int Blue_LED=6; // set blue pin of led to pin 6
int button_red_pin=8; // set button pin to pin 8
int button_green_pin=9; // set button pin to pin 9
int button_blue_pin=10; // set button pin to pin 10
int redcolor; // declaring variables
int greencolor;
int bluecolor;
int R = 0; // initialising variable
int G = 0;
int B = 0;
void setup()
{
pinMode(RED_LED,OUTPUT); // declare red pin of led as output
pinMode(Green_LED,OUTPUT); // declare green pin of led as output
pinMode(Blue_LED,OUTPUT); // declare blue pin of led as output
pinMode(button_red_pin,INPUT); // declare red button pin of led as input
pinMode(button_green_pin,INPUT); // declare green button pin of led as input
pinMode(button_blue_pin,INPUT); // declare blue button pin of led as input
Serial.begin(115200); // set a baud rate of 115200
}
void loop()
{
redcolor=digitalRead(button_red_pin); // reading values of red button and storing in variable
greencolor=digitalRead(button_green_pin); // reading values of green button and storing in variable
bluecolor=digitalRead(button_blue_pin); // reading values of blue button and storing in variable
if(redcolor == HIGH) // check the condition if red button pressed
{
delay(300);
R = R + 5; // increment the value of r by 5
if(R>255){ // increment till value of r reaches 255
R= R - 5; // decrement the value by 5
}
}
if(greencolor == HIGH) // check the condition if green button pressed
{
delay(300);
G = G + 5; // increment the value of g by 5
if(G>255){ // increment till value of g reaches 255
G = G - 5; // decrement the value by 5
}
}
if(bluecolor == HIGH) // check the condition if blue button pressed
{
delay(300);
B = B + 5; // increment the value of b by 5
if(B>255){ // increment till value of b reaches 255
B = B - 5; // decrement the value by 5
}
}
analogWrite(RED_LED,R); // passing value of r in analog write function
Serial.println(R);
analogWrite(Green_LED,G); // passing value of g in analog write function
Serial.println(G);
analogWrite(Blue_LED,B); // passing value of b in analog write function
Serial.println(B);
}
We will declare led pins as OUTPUT & push buttons as
INPUT. Also, we configure the baud rate to 115200.
We are reading the status of red, blue, and green buttons and
storing them in variable names red color, green color & blue color.
We have to use the if condition to check whether the red button, blue
button, or green button is pressed.
If conditions are satisfied we will increment the value of r
by 5 each time when the user presses the red button.
The value of r will get increment until the value of r
reaches 255. If the value of r exceeds 255 then the value of r will begin to get
decrement by 5.
Similarly, the value of g & b will increment by 5 each time when the user presses the button. The value will g and b continue to increment until it reaches 255. When it reaches 255 the value of g and b starts to decrement by 5.
Conclusion –
Today in this blog we learn about RGB led, how RGB led works, the concept of additive and subtractive color, and how we can generate different colors using primary colors. We also learn how to use RGB led sensor module with Arduino.
"I hope you find this IoT blog very helpful to you. In the upcoming lesson, we will see more about IoT sensors till then bye. See you all in my next blog."
