ESP32 KY-040 Rotary Encoder Module

🛠️ KY-040 Rotary Encoder Module Troubleshooting

This guide outlines a systematic approach to troubleshoot and resolve common problems with the . Start by confirming that the hardware connections are correct, as wiring mistakes are the most frequent cause of issues. If you are sure the connections are correct, follow the below steps to debug common issues.

❌ Unexpected Behavior or No Response

⚠️ Incorrect Direction Detection

💻 Code Examples

Below you can find code examples of KY-040 Rotary Encoder Module with ESP32 in several frameworks:

• Arduino IDE
• ESP-IDF
• ESPHome
• PlatformIO
• MicroPython

If you encounter issues while using the KY-040 Rotary Encoder Module, check the Common Issues Troubleshooting Guide.

ESP32 KY-040 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the KY-040 Rotary Encoder Module:

#define CLK_PIN 3
#define DT_PIN 4
#define SW_PIN 5

int counter = 0;
int currentStateCLK;
int lastStateCLK;
bool currentStateSW;
bool lastStateSW;

void setup() {
    pinMode(CLK_PIN, INPUT);
    pinMode(DT_PIN, INPUT);
    pinMode(SW_PIN, INPUT_PULLUP);
    lastStateCLK = digitalRead(CLK_PIN);
    lastStateSW = digitalRead(SW_PIN);
    Serial.begin(9600);
    Serial.println("KY-040 Rotary Encoder Test");
}

void loop() {
    currentStateCLK = digitalRead(CLK_PIN);
    if (currentStateCLK != lastStateCLK) {
        if (digitalRead(DT_PIN) != currentStateCLK) {
            counter++;
        } else {
            counter--;
        }
        Serial.print("Position: ");
        Serial.println(counter);
    }
    lastStateCLK = currentStateCLK;

    currentStateSW = digitalRead(SW_PIN);
    if (currentStateSW == LOW && lastStateSW == HIGH) {
        Serial.println("Button Pressed");
    }
    lastStateSW = currentStateSW;

    delay(50);
}

This Arduino code sets up the KY-040 rotary encoder using three pins: CLK (Clock), DT (Data), and SW (Switch). It initializes these pins as inputs and continuously monitors the rotation direction and button presses.

When the encoder knob is turned, the CLK and DT pins generate pulses. By comparing the sequence of these pulses, the code determines whether the encoder is rotating clockwise or counterclockwise:

• If the DT signal is opposite to the CLK signal, the counter increments (clockwise rotation).
• If the DT signal matches the CLK signal, the counter decrements (counterclockwise rotation).

The position counter is updated accordingly and printed to the serial monitor.

The built-in push-button switch (SW) is also monitored. If pressed, a message is printed to the serial monitor.

A delay(50) is used to debounce the encoder readings, ensuring stable detection of rotation and button presses.

Connect your ESP32 to your computer via a USB cable, Ensure the correct Board and Port are selected under Tools, Click the "Upload" button in the Arduino IDE to compile and upload the code to your ESP32.

ESP32 KY-040 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the KY-040 Rotary Encoder Module, here's how you can set it up and read data from the sensor. Fill in this code in the main ESP-IDF file:

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

#define CLK_PIN GPIO_NUM_18
#define DT_PIN GPIO_NUM_19
#define SW_PIN GPIO_NUM_21

volatile int counter = 0;
volatile int lastStateCLK;

void IRAM_ATTR encoder_isr_handler(void* arg) {
    int currentStateCLK = gpio_get_level(CLK_PIN);
    if (currentStateCLK != lastStateCLK) {
        if (gpio_get_level(DT_PIN) != currentStateCLK) {
            counter++;
        } else {
            counter--;
        }
        printf("Position: %d\n", counter);
    }
    lastStateCLK = currentStateCLK;
}

void app_main(void) {
    gpio_config_t io_conf = {
        .intr_type = GPIO_INTR_ANYEDGE,
        .mode = GPIO_MODE_INPUT,
        .pin_bit_mask = (1ULL << CLK_PIN) | (1ULL << DT_PIN) | (1ULL << SW_PIN),
        .pull_up_en = GPIO_PULLUP_ENABLE
    };
    gpio_config(&io_conf);

    lastStateCLK = gpio_get_level(CLK_PIN);
    gpio_install_isr_service(0);
    gpio_isr_handler_add(CLK_PIN, encoder_isr_handler, NULL);

    printf("KY-040 Rotary Encoder Test\n");
    while (1) {
        if (gpio_get_level(SW_PIN) == 0) {
            printf("Button Pressed\n");
        }
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

This ESP-IDF code configures the KY-040 rotary encoder on GPIO18 (CLK), GPIO19 (DT), and GPIO21 (SW). It uses an interrupt service routine (ISR) to detect changes in the encoder's rotation and update a counter. Additionally, it checks for button presses in the main loop and prints the status to the console.

Update the I2C pins (I2C_MASTER_SDA_IO and I2C_MASTER_SCL_IO) to match your ESP32 hardware setup, Use idf.py build to compile the project, Use idf.py flash to upload the code to your ESP32.

ESP32 KY-040 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the KY-040 Rotary Encoder Module

sensor:
  - platform: rotary_encoder
    pin_a: GPIO18
    pin_b: GPIO19
    name: "KY-040 Rotary Encoder"
    min_value: -1000
    max_value: 1000
    resolution: 1

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO21
      mode: INPUT_PULLUP
    name: "KY-040 Button"

This ESPHome configuration sets up the KY-040 rotary encoder with GPIO18 and GPIO19 for rotation detection and GPIO21 for the push button. The encoder is configured with a minimum and maximum value range, and its resolution is set to 1 step per increment.

Upload this code to your ESP32 using the ESPHome dashboard or the esphome run command.

ESP32 KY-040 PlatformIO Code Example

Example in PlatformIO Framework

For PlatformIO, make sure to configure the platformio.ini file with the appropriate environment and libraries, and then proceed with the code.

Configure platformio.ini

First, your platformio.ini should look like below. You might need to include some libraries as shown. Make sure to change the board to your ESP32:

[env:esp32]
platform = espressif32
board = esp32dev
framework = arduino

ESP32 KY-040 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the KY-040 Rotary Encoder Module:

#include <Arduino.h>

#define CLK_PIN 18
#define DT_PIN 19
#define SW_PIN 21

volatile int counter = 0;
int lastStateCLK;

void IRAM_ATTR rotary_encoder() {
    int currentStateCLK = digitalRead(CLK_PIN);
    if (currentStateCLK != lastStateCLK) {
        if (digitalRead(DT_PIN) != currentStateCLK) {
            counter++;
        } else {
            counter--;
        }
        Serial.print("Position: ");
        Serial.println(counter);
    }
    lastStateCLK = currentStateCLK;
}

void setup() {
    pinMode(CLK_PIN, INPUT);
    pinMode(DT_PIN, INPUT);
    pinMode(SW_PIN, INPUT_PULLUP);
    attachInterrupt(digitalPinToInterrupt(CLK_PIN), rotary_encoder, CHANGE);
    Serial.begin(115200);
    Serial.println("KY-040 Rotary Encoder Test");
}

void loop() {
    if (digitalRead(SW_PIN) == LOW) {
        Serial.println("Button Pressed");
        delay(100);
    }
}

This PlatformIO code configures GPIO18 (CLK), GPIO19 (DT), and GPIO21 (SW) for the KY-040 rotary encoder. It uses an interrupt to detect changes in rotation and updates a counter accordingly. The push button state is also monitored and printed to the serial monitor when pressed.

Upload the code to your ESP32 using the PlatformIO "Upload" button in your IDE or the pio run --target upload command.

ESP32 KY-040 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the KY-040 Rotary Encoder Module with your ESP32.

import machine
import time

CLK_PIN = machine.Pin(18, machine.Pin.IN, machine.Pin.PULL_UP)
DT_PIN = machine.Pin(19, machine.Pin.IN, machine.Pin.PULL_UP)
SW_PIN = machine.Pin(21, machine.Pin.IN, machine.Pin.PULL_UP)

counter = 0
last_state_clk = CLK_PIN.value()

while True:
    current_state_clk = CLK_PIN.value()
    if current_state_clk != last_state_clk:
        if DT_PIN.value() != current_state_clk:
            counter += 1
        else:
            counter -= 1
        print("Position:", counter)
    last_state_clk = current_state_clk

    if SW_PIN.value() == 0:
        print("Button Pressed")
        time.sleep(0.1)
    time.sleep(0.05)

This MicroPython script configures GPIO18 (CLK), GPIO19 (DT), and GPIO21 (SW) for the KY-040 rotary encoder. It continuously monitors the encoder rotation and updates a counter while also detecting button presses.

Upload this code to your ESP32 using a MicroPython-compatible IDE, such as Thonny, uPyCraft, or tools like ampy.