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Mini Basic PIR Sensor - BS412
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A compact passive infrared (PIR) motion sensor that detects movement from approximately 3–8 metres away. Much smaller than standard PIR modules, making it id...
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A compact passive infrared (PIR) motion sensor that detects movement from approximately 3–8 metres away. Much smaller than standard PIR modules, making it ideal for unobtrusive, space-constrained projects. Fully self-contained — just needs power, ground, and a resistor to set the delay time.
Key Features
- 3.3 V Operation – Low-voltage, low-power motion detection
- ~5 m Detection Range – Effective from approximately 3–8 m with the snap-on lens
- 120° Detection Spread – Wide field of view
- Adjustable On-Time – From 2 seconds (0 V on pin 2) up to 1 hour (3.3 V) via resistor divider
- 4 × 3 mm Sensor Window – Compact BS-series sensing element
- Breadboard Friendly – Standard pin spacing for easy prototyping
Wiring
- Pin 1 → Ground
- Pin 2 → Ground (for 2-second on-time) or resistor divider (see datasheet for values)
- Pin 3 → 3.3 V
- Pin 4 → Signal output (3.3 V high/low)
Note: This sensor runs on 3.3 V. If interfacing with a 5 V microcontroller such as Arduino, power the sensor from the 3.3 V regulator, not the 5 V rail.
Resources
- PIR Sensor Tutorial (CircuitPython and Arduino code examples)
Jargon buster
Plain-language definitions for the technical terms used above.
- CircuitPython
- A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- Motion detection
- A camera feature that checks the image for changes that suggest something has moved. It matters because your project can use movement as a trigger instead of constantly saving or processing every frame.
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Related Tutorials
Free guides on learn.littlebird.com.au
