ESP32 KY-004 Key Switch Module

🛠️ KY-004 Key Switch 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.

❌ No Response from KY-004 Module

⚠️ False Triggering of Button Press

💻 Code Examples

Below you can find code examples of KY-004 Key Switch Module with ESP32 in several frameworks:

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

If you encounter issues while using the KY-004 Key Switch Module, check the Common Issues Troubleshooting Guide.

ESP32 KY-004 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the KY-004 Key Switch Module:

#define BUTTON_PIN 7
#define LED_PIN 13

void setup() {
    pinMode(BUTTON_PIN, INPUT);
    digitalWrite(BUTTON_PIN, HIGH); // Enable internal pull-up resistor
    pinMode(LED_PIN, OUTPUT);
    Serial.begin(9600);
    Serial.println("KY-004 Key Switch Module Test");
}

void loop() {
    int buttonState = digitalRead(BUTTON_PIN);
    if (buttonState == LOW) {
        Serial.println("Button pressed");
        digitalWrite(LED_PIN, HIGH);
    } else {
        Serial.println("Button released");
        digitalWrite(LED_PIN, LOW);
    }
    delay(100);
}

This Arduino code sets up the KY-004 Key Switch Module on pin 7 and an LED on pin 13. When the button is pressed, the sensor outputs a LOW signal, turning on the LED and printing a message to the serial monitor.

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-004 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the KY-004 Key Switch 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 BUTTON_PIN GPIO_NUM_4
#define LED_PIN GPIO_NUM_2

void app_main(void) {
    gpio_set_direction(BUTTON_PIN, GPIO_MODE_INPUT);
    gpio_set_pull_mode(BUTTON_PIN, GPIO_PULLUP_ONLY);
    gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
    printf("KY-004 Key Switch Module Test\n");
    while (1) {
        int button_state = gpio_get_level(BUTTON_PIN);
        if (button_state == 0) {
            printf("Button pressed\n");
            gpio_set_level(LED_PIN, 1);
        } else {
            printf("Button released\n");
            gpio_set_level(LED_PIN, 0);
        }
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

This ESP-IDF code configures GPIO4 as an input for the KY-004 Key Switch Module and GPIO2 as an output for an LED. When the button is pressed (sensor outputs LOW), the LED turns on, and a message is printed 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-004 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the KY-004 Key Switch Module

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO4
      mode: INPUT_PULLUP
    name: "KY-004 Key Switch"
    filters:
      - delayed_on: 10ms
      - delayed_off: 10ms
    on_press:
      - then:
          - lambda: |-
              ESP_LOGD("sensor", "Button pressed!");

This ESPHome configuration sets up the KY-004 Key Switch as a binary sensor on GPIO4 with an internal pull-up resistor. It includes filtering to debounce false triggers and logs when the button is pressed.

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

ESP32 KY-004 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-004 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the KY-004 Key Switch Module:

#include <Arduino.h>

#define BUTTON_PIN 4
#define LED_PIN 2

void setup() {
    pinMode(BUTTON_PIN, INPUT_PULLUP);
    pinMode(LED_PIN, OUTPUT);
    Serial.begin(115200);
    Serial.println("KY-004 Key Switch Module Test");
}

void loop() {
    if (digitalRead(BUTTON_PIN) == LOW) {
        Serial.println("Button pressed");
        digitalWrite(LED_PIN, HIGH);
    } else {
        Serial.println("Button released");
        digitalWrite(LED_PIN, LOW);
    }
    delay(100);
}

This PlatformIO code configures the KY-004 Key Switch on GPIO4 and an LED on GPIO2. When the button is pressed, the LED turns on, and a message is printed to the serial monitor.

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

ESP32 KY-004 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the KY-004 Key Switch Module with your ESP32.

import machine
import time

BUTTON_PIN = machine.Pin(4, machine.Pin.IN, machine.Pin.PULL_UP)
LED_PIN = machine.Pin(2, machine.Pin.OUT)

while True:
    if BUTTON_PIN.value() == 0:
        print("Button pressed")
        LED_PIN.on()
    else:
        print("Button released")
        LED_PIN.off()
    time.sleep(0.1)

This MicroPython script configures the KY-004 Key Switch on GPIO4 and an LED on GPIO2. When the button is pressed (LOW signal), the LED turns on, and a message is printed to the console.

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