Hey guys… I am using a Hyperpixel 4" square on a rpi 4 to loop a number of videos 24/7. I need to cool this thing, but obviously the HP uses all the GPIO pins. I think my only option is to go with USB power.
I understand that the rpi USB port provides 1.2 amps peak power. My question:
Would this be enough power to run a small 40mm 5v Noctua fan like this one:
I believe is uses .07amps - correct?
If you look at the product photo on that page which shows the back of the rotor there is a sitcker which rates it at 0.07A. That’s usually peak, so it will probably only use that until the rotor gets up to speed and then might settle down to something like 40mA.
I had the double-thick 12V version of that (the NF-A4x20) on my desk a while ago and was running it from USB power banks just fine, so I can’t see why a USB port wouldn’t like it. You might also need to send 5V to the PWM pin but I’ve just tried this with a bigger 120mm fan and as long as you don’t ground that pin it seems to run fine.
I have the normal Hyperpixel 4 and a Pimoroni Fan Shim under it. I don’t run any script for the Fan Shim which means it’s always on, but that shouldn’t be a problem for your use :)