How can I determine whether active cooling is necessary for my application?

Question

I would like to avoid active cooling for my application, but I'm not sure how to test this short of clipping the fan wires as described here: http://jevois.org/doc/Fanless.html  From what I understand, there's no alternative way to disable the fan, is this correct?

My application involves pose estimation using ArUco markers at around 320x240 resolution, aiming for 30 FPS or better with the global shutter camera and potentially up to 20 markers visible at a time.  Is it possible to make an educated guess based on this use case?

Alternatively, is it possible to make an educated guess based on the CPU usage?

Answer 1

Yes, the fan is just connected to 5V and always on at full speed. We had some PWM speed modulation hardware logic on a previous version of the board, but that one had other issues, so finally we decided to roll back the design for mass production.

Making a guess based on CPU usage is the best. Anything below 300% should be no problem using a large heatsink like we used in that doc page you mention. We had a deep net running at 375% CPU (i.e., almost loading all 4 cores to the max) and that was stable with the heatsink.

I see DemoArUco around 220% CPU in the screenshots here: http://jevois.org/moddoc/DemoArUco/modinfo.html

So it should be no problem. Make sure you have a good thermal contact with the heatsink. You may want to spread the glue on the chip with a screwdriver or such so that it fully covers the whole chip before applying the heatsink.