ESP32 Tap Sensor (KY-031) with Arduino IDE

#Introduction

The KY-031 Tap Sensor is a vibration and knock detection module that generates a digital signal when it detects a tap, knock, or sudden vibration. It uses a spring-based sensor to detect mechanical shocks and sends a signal to the ESP32. Tap sensors are commonly used in security systems, vibration monitoring, impact detection, and automation projects. In this tutorial, we'll interface a KY-031 Tap Sensor with the ESP32 and monitor tap events through the Serial Monitor.

#Required Components

• ESP32 Board
• KY-031 Tap Sensor Module
• Jumper Wires
• Breadboard

#Pinout

#Circuit Diagram / Wiring

• KY-031 VCC → 3.3V (ESP32)
• KY-031 GND → GND (ESP32)
• KY-031 OUT → GPIO 15 (ESP32)

#Code / Programming

/* Filename: ol_tap_sensor.ino Description: Reads KY-031 Tap Sensor and prints detection status via Serial Monitor Author: www.oceanlabz.in Modification: 1/4/2025 */

#define TAP_SENSOR_PIN 15

void setup() { Serial.begin(115200); pinMode(TAP_SENSOR_PIN, INPUT); }

void loop() { int sensorState = digitalRead(TAP_SENSOR_PIN);

if (sensorState == HIGH) { Serial.println("Tap Detected"); } else { Serial.println("No Tap"); }

delay(500); }

#Explanation

• The TAP_SENSOR_PIN reads the digital output from the KY-031 Tap Sensor.
• When the sensor detects a tap, knock, or vibration, the internal spring mechanism changes state and generates a digital signal.
• The ESP32 continuously monitors the sensor output and detects tap events.
• The detection status is displayed on the Serial Monitor.

#Troubleshooting

• Ensure that the sensor is powered correctly (VCC to 3.3V and GND to GND) and that the output pin is connected to GPIO 15.
• If taps are not detected, gently tap the sensor module and verify the wiring connections.
• If the sensor triggers continuously, ensure it is mounted securely and away from excessive vibrations.
• If no messages appear in the Serial Monitor, verify that the correct COM port and ESP32 board are selected in the Arduino IDE.