I´m playing around with some PIR-Sensors (I don´t know the exact type) and I don´t have any experience in designing circuits for this type of sensor. I have googled some basic circuits and I took a look into the D203B datasheet to get some ideas how I have to design a circuit for this sensor. I want to test this one:
But the transistor doesn´t pull down the signal line. I have measured the output voltage of the sensor and my oscilloscope displays a voltage of 520 mV, but this voltage doesn´t change when I move my finger in front of the sensor. So I´m pretty unsure if this sensor is broken or if my circuit is "too cheap".
Output of sensor is miliVolts, not enough to control MOSFET. If you mean to apply the amplifier circuit in that document it is good point to start. But you should keep in mind that sensor does not work without lenses. The sensor is differenial types and IR radiation should be different to each half. Lenses create this pattern and transfer radiation only nessesary band. Quality of lenses affect sensitivity