Connecting the Mini IR Pyroelectric Infrared PIR Motion Human Sensor Detector Module. This guide is detail guide for one of the sensor types on this guide here: Infrared motion detection

We found no official name for this sensor but its sold as “Mini IR Pyroelectric Infrared PIR Motion Human Sensor Detector Module”. WARNING do not attempt to connect it directly. Specs on its output pin on the net were fluctuating from 3.3V to 4 V so I measured just in case and found it to be 4.4 V !
This sensor costs about $2.2 on Ali express.
Specs are supposed to be something like this:
Working voltage: DC 4.5-20V
Static current: <55uA
Electronic level output: High 3.3V/Low 0V (Some sellers listed this as 4V but I measured it as 4.4 V ! So assume its 4.4 V to be safer)
Trigger mode: Repeated triggering
Blockade time: 2.5S
Detective angle: <100°
Induction distance: less than 3m
Working temperature: -20—+80
First problem is that this sensor does not come with pins soldered on it. And since the sensor is really small, only 10 mm wide then normal header pins will not fit (It is actually smaller than it seems on the picture, it is smaller than finger nail). So in the end I soldered wires directly to it which was a bit of detail work. Also clamped the 3 wires together to keep it nice and tidy. Then it ended like this:
Red to VCC (5 V)
Blue to GND
Yellow to OUT
Because the voltage output is clearly to high for GPIO, then do not connect the out pin on this sensor directly to the GPIO pin. Instead we need to lower the voltage on the output like shown here bellow:
R1 we choose as 1kΩ
So we can calculate:
3,3 = 4.4 * (1000 / (R + 1000))
0.75 = (1000 / (R + 1000))
0.75R + 750 = 1000
0.75R = 250 Ω
R = 333 Ω ->
Nearest resistor above it was 360 Ω which is good we use that