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ESP32 - GPIO Interrupt

ESP32 - SW-420 Vibration Sensor

The SW-420 vibration sensor module can catch shocks, knocks, and shaking that happen around it, turning a simple mechanical disturbance into a digital signal your ESP32 can act on.

In this tutorial, we will learn how to use the ESP32 and a SW-420 vibration sensor to detect vibration. We will delve into the following:

Connecting the SW-420 vibration sensor to the ESP32
Programming the ESP32 to detect vibration using the SW-420 vibration sensor.

Once the basic detection is working, you can extend the code to sound a buzzer, flash an LED, or send a notification whenever vibration is picked up.

This tutorial shows how to program the ESP32 using the Arduino language (C/C++) via the Arduino IDE. If you’d like to learn how to program the ESP32 with MicroPython, visit this ESP32 MicroPython - SW-420 Vibration Sensor tutorial.

Hardware Used In This Tutorial

1	×	38-pin ESP32 ESP-WROOM-32 Dev Module - Narrow
1	×	Alternatively, 38-pin ESP32 ESP-WROOM-32 Dev Module - Wide
1	×	Alternatively, 30-pin ESP32 ESP-WROOM-32 Dev Module - Wide
1	×	Alternatively, ESP32 Uno-form board
1	×	Alternatively, ESP32 S3 Uno-form board
1	×	USB Cable Type-A to Type-C (for USB-A PC)
1	×	USB Cable Type-C to Type-C (for USB-C PC)
1	×	SW-420 Vibration Sensor Module
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, 5V Power Adapter for ESP32
1	×	Recommended: Screw Terminal Expansion Board for ESP32
1	×	Recommended: Breakout Expansion Board for ESP32
1	×	Recommended: Power Splitter for ESP32

Or you can buy the following kits:

1	×	DIYables ESP32 Starter Kit (ESP32 included)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links in this section are Amazon affiliate links, meaning we may earn a commission at no additional cost to you if you make a purchase through them. Additionally, some links direct you to products from our own brand, DIYables .

Introduction to SW-420 Vibration Sensor

The SW-420 vibration sensor module is built to notice shocks and shaking in whatever it is mounted on. Inside the module, a small spring-based vibration switch sits near a metal contact; an onboard LM393 comparator watches that switch and outputs a clean digital signal whenever vibration or shock disturbs it, while an onboard potentiometer lets you set how much shaking is needed to trigger the output.

The SW-420 Vibration Sensor Pinout

The SW-420 vibration sensor has three pins:

VCC pin: needs to be connected to VCC (3.3V to 5V)
GND pin: needs to be connected to GND (0V)
DO pin: is an output pin: LOW when the sensor is idle and HIGH when vibration or shock is detected. This pin needs to be connected to ESP32's input pin.

image source: diyables.io

The SW-420 vibration sensor module has two LED indicators:

One LED indicator shows the power status.
Another LED indicator lights up whenever the DO pin goes HIGH, signaling that vibration has been detected.

How It Works

Here's how the output pin of the sensor behaves:

When the module sits still, the internal switch stays open and the output pin is set to LOW.
When vibration or shock disturbs the module, the internal switch closes momentarily and the output pin is set to HIGH.

Wiring Diagram

How to connect ESP32 and SW-420 vibration sensor using breadboard

This image is created using Fritzing. Click to enlarge image

How to connect ESP32 and SW-420 vibration sensor using screw terminal block breakout board

How to connect ESP32 and SW-420 vibration sensor

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: The best way to Power ESP32 and sensors/displays.

How To Program For SW-420 Vibration Sensor

Initializes the ESP32 pin to the digital input mode by using pinMode() function. For example, pin GPIO18

pinMode(18, INPUT);

Reads the state of the ESP32 pin by using digitalRead() function.

int vibrationState = digitalRead(18);

ESP32 Code - Detecting the vibration

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-sw-420-vibration-sensor */ #define SENSOR_PIN 18 // ESP32 pin GPIO18 connected to the DO pin of the SW-420 vibration sensor int lastState = LOW; // the previous state from the input pin (idle/resting state) int currentState; // the current reading from the input pin void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); // initialize the ESP32's pin as an input pinMode(SENSOR_PIN, INPUT); } void loop() { // read the state of the ESP32's input pin currentState = digitalRead(SENSOR_PIN); if (lastState == LOW && currentState == HIGH) Serial.println("Vibration detected"); else if (lastState == HIGH && currentState == LOW) Serial.println("Vibration stopped"); // save the the last state lastState = currentState; }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to ESP32
Tap or shake the SW-420 sensor
See the result on Serial Monitor.

Newbiely | Arduino IDE 2.3.8

──

☐

Newbiely.ino

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8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'ESP32 Dev Module' on 'COM15')

New Line

9600 baud

Vibration detected Vibration stopped Vibration detected Vibration stopped

Ln 11, Col 1

ESP32 Dev Module on COM15

From here, you are free to personalize the code so it sounds a buzzer, flashes an LED, or sends an alert whenever vibration is detected. For more detailed guidance and step-by-step instructions, you can refer to the tutorials provided at the end of this tutorial.

Troubleshooting

If you encounter any issues with the SW-420 vibration sensor's functionality, please consider the following troubleshooting steps:

Adjust the sensitivity: Turn the onboard potentiometer to make the sensor more or less sensitive if it triggers too easily or not at all.
Isolate from ambient vibration: Mount the sensor away from motors, fans, or surfaces that vibrate constantly, as this can cause continuous false triggers.
Check the wiring: Make sure the VCC, GND, and DO pins are connected correctly.
Check the power supply: Ensure that the power supply is clean and stable for consistent readings.

Video Tutorial

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Function References

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