ESP32 KY-031 Knock Sensor Module

🛠️ KY-031 Knock Sensor 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 Sensor

⚠️ False Triggering

💻 Code Examples

Below you can find code examples of KY-031 Knock Sensor Module with ESP32 in several frameworks:

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

If you encounter issues while using the KY-031 Knock Sensor Module, check the Common Issues Troubleshooting Guide.

ESP32 KY-031 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the KY-031 Knock Sensor Module:

int knock = 10; // Sensor input pin
int value; // Variable to store sensor value

void setup() {
    pinMode(knock, INPUT); // Initialize sensor pin as input
    Serial.begin(9600); // Initialize serial communication
    Serial.println("KY-031 Knock test");
}

void loop() {
    value = digitalRead(knock); // Read sensor value
    if (value == LOW) { // If knock detected
        Serial.println("Knock recognized");
        delay(200); // Delay to avoid multiple detections
    }
}

This Arduino code initializes the sensor input pin and serial communication. In the loop, it continuously reads the sensor value and prints "Knock recognized" to the serial monitor when a knock is detected.

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-031 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the KY-031 Knock Sensor 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 KNOCK_SENSOR_PIN GPIO_NUM_16

void app_main(void) {
    gpio_config_t io_conf = {
        .intr_type = GPIO_INTR_NEGEDGE, // Interrupt on falling edge
        .mode = GPIO_MODE_INPUT,
        .pin_bit_mask = (1ULL << KNOCK_SENSOR_PIN),
        .pull_up_en = GPIO_PULLUP_ENABLE
    };
    gpio_config(&io_conf);

    gpio_install_isr_service(0);
    gpio_isr_handler_add(KNOCK_SENSOR_PIN, knock_isr_handler, NULL);

    printf("KY-031 Knock Sensor Test\n");
    while (1) {
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

void IRAM_ATTR knock_isr_handler(void* arg) {
    printf("Knock detected!\n");
}

This ESP-IDF code configures GPIO16 as an input with an interrupt on the falling edge. When a knock is detected, an interrupt service routine (ISR) is triggered, printing "Knock detected!" 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-031 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the KY-031 Knock Sensor Module

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO16
      mode: INPUT_PULLUP
    name: "KY-031 Knock Sensor"
    filters:
      - delayed_off: 200ms

This ESPHome configuration sets up a binary sensor for the KY-031 knock sensor connected to GPIO16. It uses a delayed_off filter to prevent multiple detections from a single knock.

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

ESP32 KY-031 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-031 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the KY-031 Knock Sensor Module:

#include <Arduino.h>

#define KNOCK_SENSOR_PIN 16

void setup() {
    pinMode(KNOCK_SENSOR_PIN, INPUT_PULLUP);
    Serial.begin(115200);
    Serial.println("KY-031 Knock Sensor Test");
}

void loop() {
    if (digitalRead(KNOCK_SENSOR_PIN) == LOW) {
        Serial.println("Knock detected!");
        delay(200); // Debounce delay
    }
    delay(50);
}

This PlatformIO code sets up GPIO16 as an input with a pull-up resistor for the KY-031 knock sensor. When a knock is detected, a message is printed to the serial monitor, and a debounce delay of 200ms prevents false triggers.

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

ESP32 KY-031 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the KY-031 Knock Sensor Module with your ESP32.

import machine
import time

KNOCK_SENSOR_PIN = machine.Pin(16, machine.Pin.IN, machine.Pin.PULL_UP)

while True:
    if KNOCK_SENSOR_PIN.value() == 0:
        print("Knock detected!")
        time.sleep(0.2)  # Debounce delay
    time.sleep(0.05)

This MicroPython script configures GPIO16 as an input with a pull-up resistor for the KY-031 knock sensor. It continuously checks for knocks and prints a message when one is detected, with a debounce delay to prevent multiple detections from a single event.

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