I tried to find out the correct wiring for a HC-SR501 PIR sensor.
I thought that the second circuit diagram (digital isolated input example)
would be correct and that I have to select a suitable resistor.
But I got different voltage ranges for low / high if I either sourced only from the 12V battery within BOX102 or with the power supply to charge the 12V battery.
I sourced the PIR and the RUT955 together because the PIR should be suitable for 9 or 12V input voltage.
As resistor values I tried 470, 1k, 1,5k and 2,2kOhms.
It seems to be that the PIR started to toggle between low and high logical states.
I am not really sure if the digital isolated input example is correct for the HC-SR501 PIR
Are the voltage ranges for low and high logic level correct?
I measured high starting at 7,8V. with 1kOhms.
Which circuit diagram is fool proof?
Any hint appreciated.