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I'm planning to build a security camera with a Raspberry Pi 4B in it with the camera being an IR camera I found online. Being a security camera, I'm planning to put it outside my house. Where I live it's relatively dry, but there can still be quite a bit of condensation going on and still have drops of water/snow still finding its way inside the camera enclosure (which only has some ventilation holes on the bottom side). I'm afraid that the water in the enclosure can form on the Raspberry Pi and might end up causing damage to the traces or a short-circuit. To prevent that from happening, I'm planning to add some silicone conformal coating on the Raspberry Pi.

My problem is that I'm not too sure where exactly to apply the conformal coating to on the RPi PCB. For example for the top side of the PCB, would everything except for the CPU, GPIO pins and camera slot be covered in the coating? As for the bottom side of the RPi, how would the SD card slot and SD card (if necessary) be coated (perhaps SD card inside the slot already and coat both the slot and the card). For the USB plugs on the side as well as all the IO plugs like display outs and audio jack's insides have to be coated or just be plugged up somehow?

I haven't been able to find much on this topic online and would really appreciate any help, thanks!

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I've conformal coated a raspberry pi before without any noticeable ill effect.

You should entirely avoid all the connectors (unless you don't mind destroying them). Even if you place a mating cable or the sd card in a connector, the conformal coating will tend to wick into the empty spaces and jam it up. Just keep the conformal coating away from them.

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  • \$\begingroup\$ Got it, will keep the CC away from the connectors in that case! Just curious though, is it possible for moisture to damage the connectors since they're uncoated or is it something that isn't necessary to worry about? Also, just another quick question, is it necessary to cover up the memory and controllers on the Pi as well or should I just coat around it? \$\endgroup\$
    – Hao C.
    Commented Sep 20, 2021 at 7:53
  • \$\begingroup\$ Yes the connectors can be damaged by moisture, if water gets in there current can flow between the pins and electrolysis may occur. I would only consider conformal coating to be supplemental protection. It will not make the board fully waterproof. Conformal coating works well in combination with partially shielded enclosures which prevent direct spray/dripping. A cctv camera enclosure is a perfect example of this. \$\endgroup\$
    – Drew
    Commented Sep 20, 2021 at 17:56
  • \$\begingroup\$ Ah I see, thanks so much for the help! \$\endgroup\$
    – Hao C.
    Commented Sep 20, 2021 at 18:02

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