PIR sensors are super useful for detecting motion from pets, humanoids, and even potentially zombies from up to 5 meters away. This BS412 sensor is much smaller than most PIR modules, making it perfect for projects where you don't want it to stand out. It's fully - contained, only needing power, ground, and a resistor to set the delay time, and it's easy to use on a breadboard or perfboard. It runs on 3.3V power. If you're using it with an Arduino or other 5V chips, power it from the 3V regulator. The digital signal output is 3.3V high/low. You can adjust the time the signal pin stays high from 2 seconds to one hour by connecting a resistor to the second pin. Check the datasheet 'on time' table for the right resistor values. The snap - on lens is focused at 5 meters with a 120 - degree spread and works from about 3 to 8 meters. It's smaller and cheaper than our other PIR modules. Its performance is decent, though not as good as larger modules, with a narrower range and longer trigger time. For PIR tutorials with CircuitPython and Arduino code examples, visit Adafruit's PIR sensor tutorial page. The BS sensor window is 4mm x 3mm. We also have the more sensitive BL412 PIR sensor with a larger sensing element.
Using this PIR sensor is easy. First, refer to the datasheet page 7 pin - out diagram. Connect pin #1 to the ground, pin #2 to the ground for a 2 - second on - time, and pin #3 to 3.3V. Then, check the signal on pin #4. Remember, it runs on 3.3V power. If you're using it with a 5V device like an Arduino, power it from the 3V regulator. You can change how long the signal pin stays high by connecting a resistor to the second pin. Just look at the 'on time' table in the datasheet to pick the right resistor. The sensor's lens is set for 5 meters with a 120 - degree spread, but it can work from 3 to 8 meters. It's smaller and less expensive, but don't expect the same performance as larger modules. As for maintenance, keep it clean and away from extreme conditions. If you want more help, check out Adafruit's PIR sensor tutorial page with code examples and project ideas.
