Hello
I have six unused petite 101 PIRs left over from an old alarm. I want to use them to trigger cameras but am having problems reading the signal from the circuit. My understanding is that when the PIR is tripped it will open the circuit between N and C (the alarm contacts). It says it is a "Positive looped normally closed circuit".
I have found a digital copy of the PIR leaflet at
https://www.google.co.uk/url?sa=t&r...SZdkQwabZ9hK4f-6g&sig2=_k6iAgip2TC15xaueJimbg
When the PIR is triggered the LED (on the PIR board) lights for a short time and goes off but there does not seem to be any change in the signal on the alarms contacts N/C.
I have looked on the internet and a lot of people seems to use the LED circuit but I want to use the N/C contacts.
I have tried measuring the resistance between N and C
and the voltage difference but there does not seem to be any change.
If I just connect a voltage (12V or 5V or 3.3V) to C and and an LED followed by a resistor on N and go to ground then the LED stays on. (either way round)
I thought maybe it was because the signal was too short so I read N using an interrupt on an Arduino (with a pull down resistor) and there is no change.
I have tried 5 of the 6 PIRs and get the same result so I don't think they are faulty.
Am I missing something? What is this signal supposed to look like?
Thanks
Mrs Z
I have six unused petite 101 PIRs left over from an old alarm. I want to use them to trigger cameras but am having problems reading the signal from the circuit. My understanding is that when the PIR is tripped it will open the circuit between N and C (the alarm contacts). It says it is a "Positive looped normally closed circuit".
I have found a digital copy of the PIR leaflet at
https://www.google.co.uk/url?sa=t&r...SZdkQwabZ9hK4f-6g&sig2=_k6iAgip2TC15xaueJimbg
When the PIR is triggered the LED (on the PIR board) lights for a short time and goes off but there does not seem to be any change in the signal on the alarms contacts N/C.
I have looked on the internet and a lot of people seems to use the LED circuit but I want to use the N/C contacts.
I have tried measuring the resistance between N and C
and the voltage difference but there does not seem to be any change.
If I just connect a voltage (12V or 5V or 3.3V) to C and and an LED followed by a resistor on N and go to ground then the LED stays on. (either way round)
I thought maybe it was because the signal was too short so I read N using an interrupt on an Arduino (with a pull down resistor) and there is no change.
I have tried 5 of the 6 PIRs and get the same result so I don't think they are faulty.
Am I missing something? What is this signal supposed to look like?
Thanks
Mrs Z