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Arduino - SW520D Tilt Sensor

The SW520D tilt sensor module (also known as a ball switch or angle sensor) is capable of detecting tilt or orientation changes. It can be used to create tilt-reactive projects, such as an alarm that triggers when an object is moved or a servo motor that responds to orientation.

In this tutorial, we are going to learn how to use Arduino and a SW520D tilt sensor to detect tilt. In detail, we will learn:

How to connect the SW520D tilt sensor to Arduino
How to program Arduino to detect tilt using the SW520D tilt sensor

Afterward, you can tweak the code to make it activate an LED or a light (via a relay) when it detects a tilt, or even make a servo motor rotate.

Hardware Required

1	×	Official Arduino Uno
1	×	Alternatively, DIYables STEM V3, Fully Compatible with Arduino Uno R3
1	×	USB 2.0 cable type A/B (for USB-A PC)
1	×	USB 2.0 cable type C/B (for USB-C PC)
1	×	SW520D Tilt Sensor Module
1	×	Jumper Wires
1	×	Recommended: Screw Terminal Block Shield for Arduino Uno
1	×	Recommended: Sensors/Servo Expansion Shield for Arduino Uno
1	×	Recommended: Breadboard Shield for Arduino Uno
1	×	Recommended: Enclosure for Arduino Uno
1	×	Recommended: Prototyping Base Plate & Breadboard Kit for Arduino UNO

Or you can buy the following kits:

1	×	DIYables STEM V3 Starter Kit (Arduino included)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some links in this section are Amazon affiliate links. If you make a purchase through these links, we may earn a commission at no extra cost to you.
Additionally, some links direct to products from our own brand, DIYables .

About SW520D Tilt Sensor

The SW520D tilt sensor module can be used to detect tilt or orientation changes in the surrounding environment. Inside the module, there is a small metal ball that rolls between two electrical contacts depending on the tilt angle. The module outputs a simple digital signal (ON/OFF), which makes it easy to interface with Arduino.

The SW520D Tilt Sensor Pinout

The SW520D tilt 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: HIGH when the sensor is upright and LOW when the sensor is tilted. This pin needs to be connected to Arduino's input pin.

image source: diyables.io

The SW520D tilt sensor module also has two LED indicators:

One LED indicator for power
One LED indicator for the tilt state: on when the sensor is upright, off when it is tilted

How It Works

When the sensor is upright, the metal ball inside closes the contact, and the output pin is HIGH.
When the sensor is tilted, the metal ball inside opens the contact, and the output pin is LOW.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

How To Program For SW520D Tilt Sensor

Initializes the Arduino pin to the digital input mode by using pinMode() function. For example, pin 5

pinMode(5, INPUT);

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

int tiltState = digitalRead(5);

Arduino Code - Detecting the tilt

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-sw520d-tilt-sensor */ // Arduino's pin connected to DO pin of the SW520D tilt sensor #define SENSOR_PIN 5 int lastState = HIGH; // the previous state from the input pin int currentState; // the current reading from the input pin void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); // initialize the Arduino's pin as an input pinMode(SENSOR_PIN, INPUT); } void loop() { // read the state of the the input pin: currentState = digitalRead(SENSOR_PIN); if (lastState == HIGH && currentState == LOW) Serial.println("The tilt has been detected"); else if (lastState == LOW && currentState == HIGH) Serial.println("The tilt has disappeared"); // save the the last state lastState = currentState; }

Quick Steps

Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to Arduino
Tilt the SW520D sensor back and forth
See the result on Serial Monitor.

Newbiely | Arduino IDE 2.3.8

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Newbiely.ino

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

Output

Serial Monitor

Message (Enter to send message to 'Arduino Uno' on 'COM15')

New Line

9600 baud

The tilt has been detected The tilt has disappeared The tilt has been detected The tilt has disappeared

Ln 11, Col 1

Arduino Uno on COM15

Now we can customize the code to activate an LED or a light when a tilt is detected, or even make a servo motor rotate. You can find more information and step-by-step instructions in the tutorials provided at the end of this tutorial.

Troubleshooting

If the SW520D tilt sensor is not working properly, try the following steps:

Check the orientation: The SW520D is sensitive to its mounting orientation. Make sure it is installed in the correct upright position for reliable detection.
Reduce vibrations: The tilt sensor can also pick up mechanical vibrations. Mounting it on a solid surface can help minimize 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 stable for consistent readings.

Video Tutorial

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Function References

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