I have two pi5s, originally both with the original ‘active cooler for pi5’ and now one with ’ Argon NEO 5 M.2 NVME’ and the other with ’ Argon ONE V3 M.2 NVME’ cases.
I am able to monitor fan speed via /sys/devices/platform/cooling_fan/hwmon/hwmon2/fan1_input with the active coolers and the NEO 5 - but not with the argon one v3. (in fact the whole /sys//devices/platform/cooling_fan tree no longer exists on that p5).
It might be relevant that now, (only on the one v3), the fan is driven by some magic, and not pluggen-in to the fan header on the pi5 (but still works ok)
Is there some other place or magic command that I can read the speed from?
If you remove the board from the top part of the case, you’ll find that the fan has a standard 4-pin connector and plenty enough cable to route it to the connector on the pi5 board. I did this last night, tested it under load, and the fan came on and read back RPM through hwmon.
I was looking for a solution to run the fan without any scripts because I am using Home Assistant with my Pi 5 never thought to look under the hood for the fan connector.
I managed to loop the wire to the top right near the GPIO pins but I guess it’ll make it a bit tricky when removing the board from the case as you might yank the wire off.
It’s not perfect, but it’s long enough to not be under strain or pinched… And how often will you take it apart? The PCI-E cable for the NVME is a tighter fit if you ask me. Plus you don’t have to run some janky script to control your fan.