Mini Basic PIR Sensor - BL412

PIR sensors are super useful for detecting motion from pets or humanoids up to about 5 meters away, and who knows, maybe even zombies (though it's not guaranteed). This BL412 sensor is much smaller than most PIR modules, making it perfect for projects where you don't want it to stand out. It's self - contained and only needs power, ground, and a resistor to set the delay time. It's also easy to use on a breadboard or perfboard. It runs on 3.3V power. So, 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 how long the signal pin stays high by connecting a resistor to the second pin, with the time ranging from 2 seconds (at 0V) up to one hour (at 3.3V). Check the datasheet's 'on time' table for the right resistor values. To use it, refer to the datasheet page 7 pin - out diagram. Connect pin #1 to ground, pin #2 to ground for a 2 - second on time, pin #3 to 3.3V, and then check the signal on pin #4. The snap - on lens is focused at 5 meters with a 120 - degree spread and works from about 3 to 8 meters. These sensors are smaller and cheaper than our other PIR modules. The performance is decent but not as good as larger modules, with a smaller range and longer trigger time. For a PIR tutorial with CircuitPython and Arduino code examples and project ideas, visit our PIR sensor tutorial page! The BL sensor window is 5mm x 3.8mm, and we also have the BS412 PIR sensor with a smaller sensing element.

Using this PIR sensor is quite straightforward. First, make sure you power it with 3.3V. If you're using it with a 5V device like an Arduino, use the 3V regulator for power. Then, follow the pin - out diagram on page 7 of the datasheet. Connect pin #1 to the ground, pin #2 to the ground if you want a 2 - second on time, and pin #3 to the 3.3V power. After that, you can check the signal on pin #4. You can change how long the signal stays high by connecting a resistor to the second pin. Look at the 'on time' table in the datasheet to pick the right resistor. Note that the sensor's range is about 3 to 8 meters, with the best focus at 5 meters and a 120 - degree spread. Its performance might not be as good as larger modules, with a shorter range and longer trigger time. For maintenance, keep it clean and dry. If you want to learn more about using it with CircuitPython or Arduino, check out our PIR sensor tutorial page.