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Arduino - Rotary Encoder LED
In this tutorial, We are going to learn how to program Arduino to control the brightness of a LED according to the rotary encoder's output value.
Hardware Required
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Additionally, some links direct to products from our own brand, DIYables.
About LED and Rotary Encoder
If you do not know about LED and rotary encoder (pinout, how it works, how to program ...), learn about them in the following tutorials:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Arduino Code
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-rotary-encoder-led
*/
#include <Servo.h>
#define CLK_PIN 2
#define DT_PIN 3
#define SW_PIN 4
#define LED_PIN 9
#define DIRECTION_CW 0 // clockwise direction
#define DIRECTION_CCW 1 // counter-clockwise direction
int counter = 0;
int direction = DIRECTION_CW;
int CLK_state;
int prev_CLK_state;
int brightness = 125; // middle value
void setup() {
Serial.begin(9600);
// configure encoder pins as inputs
pinMode(CLK_PIN, INPUT);
pinMode(DT_PIN, INPUT);
// read the initial state of the rotary encoder's CLK pin
prev_CLK_state = digitalRead(CLK_PIN);
pinMode(LED_PIN, OUTPUT);
}
void loop() {
// read the current state of the rotary encoder's CLK pin
CLK_state = digitalRead(CLK_PIN);
// If the state of CLK is changed, then pulse occurred
// React to only the rising edge (from LOW to HIGH) to avoid double count
if (CLK_state != prev_CLK_state && CLK_state == HIGH) {
// if the DT state is HIGH
// the encoder is rotating in counter-clockwise direction => decrease the counter
if (digitalRead(DT_PIN) == HIGH) {
direction = DIRECTION_CCW;
counter--;
brightness -= 10; // you can change this value
} else {
// the encoder is rotating in clockwise direction => increase the counter
direction = DIRECTION_CW;
counter++;
brightness += 10; // you can change this value
}
if (brightness < 0)
brightness = 0;
else if (brightness > 255)
brightness = 255;
// sets the brightness of LED according to the counter
analogWrite(LED_PIN, brightness);
Serial.print("COUNTER: ");
Serial.print(counter);
Serial.print(" | BRIGHTNESS: ");
Serial.println(brightness);
}
// save last CLK state
prev_CLK_state = CLK_state;
}
Quick Steps
- Connect Arduino to PC via USB cable
- Open Arduino IDE, select the right board and port
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to Arduino
- Open Serial Monitor
- Rotate the rotary encoder
- See the LED's brightness
- See the result on Serial Monitor
COM6
COUNTER: 1 | BRIGHTNESS: 135
COUNTER: 2 | BRIGHTNESS: 145
COUNTER: 3 | BRIGHTNESS: 155
COUNTER: 4 | BRIGHTNESS: 165
COUNTER: 5 | BRIGHTNESS: 175
COUNTER: 6 | BRIGHTNESS: 185
COUNTER: 7 | BRIGHTNESS: 195
Autoscroll
Clear output
9600 baud
Newline
Code Explanation
Read the line-by-line explanation in comment lines of source code!
Video Tutorial
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