PROJECT 2: Mini Basic PIR Sensor - BS412

Product page here

RESEARCH

The produce page says that the Mini Basic PIR Sensor detects motion from up to 5 meters away and is extremely small. The datasheet suggests it can be used for intelligent appliances, alarms, motion detector, as a sensor lamp switch, security systems, and automatic control. It can only take up to 3.6 volts for power. 

In testing it out, I found the range to be more like 2 meters (~6 feet). 

CIRCUIT

I found the circuit difficult to put together - there is little documentation on it and the datasheet is confusing to read. I tried a few different configurations and each time the sensor felt hot to the touch. 



I got it to work just my trial and error - turns out I read the diagram wrong and I had the power & signal wires swapped. I used parts of this code i found on the Adafruit site. At first, I just used the LED pin on the Arduino itself because I couldn’t get a standalone one to work. This is the code I used:


I found there to be a little delay when the motion is no longer detected, as shown here. It detects the motion quickly, but takes a little while for it to register that the motion has ended. Here’s footage of me testing it out with a standalone LED.