g2c
Member
Hello friends,
I am using 13 PIRs detector around the house, both for intrusion detection (in armed state) as for lighting (disarm state) the elements I'm using are of ref HC-SR501. They work quite reliably once you replace the pots by a resistor (or a short for the pulse width). The main issue is that oftentimes, when it's windy and raining, some elements start oscillating and send (to the Ino measuring the pulse density) a pulse every ~5” which is interpreted as an intrusion.
The PIRs are housed in a kind of aluminum plate screwed to the wall, picture attached , the wall surface is rough and the Fresnel lens mounting is not hermetic either. It is practically impossible to keep the PIR elements in a dry atmosphere
Now, a friend, aware of mil technology, told me that the mils often coat their PCB with some kind of coating that makes them insensitive to humidity. This coating can even be dissolved if a rework is required on the PCB and I was wondering if anyone has experienced this technic? if so, what kind of coating? or has other ones to overcome my problem?
I am using 13 PIRs detector around the house, both for intrusion detection (in armed state) as for lighting (disarm state) the elements I'm using are of ref HC-SR501. They work quite reliably once you replace the pots by a resistor (or a short for the pulse width). The main issue is that oftentimes, when it's windy and raining, some elements start oscillating and send (to the Ino measuring the pulse density) a pulse every ~5” which is interpreted as an intrusion.
The PIRs are housed in a kind of aluminum plate screwed to the wall, picture attached , the wall surface is rough and the Fresnel lens mounting is not hermetic either. It is practically impossible to keep the PIR elements in a dry atmosphere
Now, a friend, aware of mil technology, told me that the mils often coat their PCB with some kind of coating that makes them insensitive to humidity. This coating can even be dissolved if a rework is required on the PCB and I was wondering if anyone has experienced this technic? if so, what kind of coating? or has other ones to overcome my problem?
