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Tilt Sensor Module SW520D

15-07-2025

🤔 What is a Tilt Sensor?

A tilt sensor (also called a ball switch or mercury switch) is a digital switch that changes its output based on orientation. When tilted beyond a certain angle, the internal mechanism (metal ball or mercury drop) makes or breaks contact, changing the signal.

📌 Key Features:

Simple ON/OFF output
Detects if the object is upright or tilted
Digital signal (HIGH or LOW)
No orientation angle info — only tilt or no tilt

📦 Types of Tilt Sensors:

Type	Inside it	Behavior
Metal ball type	Rolling metal ball	Conducts when level
Mercury type	Liquid metal drop	Conducts when tilted
MEMS Tilt Module	Accelerometer-based	Gives angle info

We'll focus on the basic ball type, which is easiest to use with ESP32.

🧰 Components Needed:

ESP32 board
Tilt sensor module (KY-017, SW-520D, or similar)
Jumper wires
LED (optional for output)

🧪 How It Works:

Inside the sensor is a small metal ball.
When upright → ball connects two metal contacts → Circuit closed → Output LOW
When tilted → ball breaks contact → Circuit open → Output HIGH (or floating)

Some modules have built-in pull-up resistors and LED to indicate state.

🔌 Wiring Tilt Sensor to ESP32

Tilt Sensor Pin	ESP32 Pin
VCC	3.3V or 5V
GND	GND
OUT	GPIO 14 (or any digital pin)

🧠 What This Code Does:

Reads digital value from the sensor.
If LOW: the sensor is upright.
If HIGH: the sensor is tilted.
LED shows the state.

💡 Real-world Applications

Use Case	Description
🛠️ Anti-Tamper Alarm	Alert when a box/device is moved
🔒 Laptop Security	Lock or alert if tilted or stolen
🎮 Game Controller	Basic motion control in DIY games
🛑 Vehicle Crash Alert	Detect if a device tips over
📦 Package Monitoring	Detect tilting during delivery/shipping

🛠️ Sensor Not Working? Troubleshooting:

Problem	Fix
No response	Check VCC, GND, and OUT connection
Inverted readings	Try changing logic (HIGH/LOW check)
Floating output	Add external pull-up/down resistor
No LED on module	Try tilting more or check supply voltage