I have built a device based on Raspberry Pi who have to be located on a house's roof.
I use an IP67 enclosure with IP69 pressure compensation element with gore-tex membrane. I add silica gel before closing the enclosure.
I have seen that 3 chips are very hot (+-30°C more than ambient temperature) in normal external temperature (power regulator, ethernet and arm chip). I will add a passive heat sink on those three components.
I will underclock the ARM to match with performance needs.
Do you have another idea to avoid premature failure of electronics due to humidity/temperature?
Best Answer
This box has suffered 80F-plus direct sun exposure, survived weeks buried under ice and snow, even several days completely submerged. The heatsink was robbed from a Pentium II processor and mounted to the box with the screws tapped into the plastic. "25 Year" Silicon seals the heatsink to the plastic case. The internals show no sign of contamination.
"Silicone," now THAT'S funny!!! (grin)
This box has a "vent." Inside this cabinet is a 12VDC 500W, fan cooled power supply.
In the upper right hand corner I placed a right-angle cable "box-end" connector. Inside the connecter is a round patch of Scotch-Brite dish scrubber (http://www.scotch-brite.com/wps/portal/3M/en_US/Scotch-BriteBrand/Scotch-Brite/Products/Product-Catalog/~/Heavy-Duty-Scour-Pad?N=4337+3294631680&rt=rud) - helps keep the tiny critters out.