Fan control for a Raspberry Pi 3b+ possible?

Can’t find infos about a fan control for a Raspberry Pi 3b+. Is this possible and is there a program that can manage this control?

Micky

See CPUclock

CPU ≠ Fan :-o

On my 3B+, I just whacked the fan on to the 3.3V pins. So it runs a little slower than on 5V, but it’s also quieter. The CPU has a radiator-type heatsink, so that combination keeps it suitably cool. Right now the core temperature is 43°C.
I also have CPUClock running to throttle back the clock speed if the thing gets too hot (I’ve set it to throttle at 55°C). It only sort of gets there in the mid-summer heat. If you’re less paranoid and consider 65-70°C to be a throttle point, it just won’t. Not with a grille heatsink and little 1" fan over it.

YMMV with other systems. Remember RISC OS barely uses the GPU and only one core, so it’s not exactly pushing the hardware…

The Pi2 (ARMv7) that I’m using (in the living room) just has a passive grille type heatsink on both the SoC and the network/USB chips, and it’s running at 55°C. I’ve not set an autothrottle as it rarely gets beyond that. Again, only one core…

The help for CPUclock does say If CPUClock is running on a Raspberry Pi, fitted with a RaPi fan, it can switch the fan on or off at a user defined cpu temperature but I know no more than that.

There is this: https://www.riscosbits.co.uk/fhantom.htm

I sit corrected. Just looked at the web site, should’ve checked the app.

CPUClock is able to switch the fan on/off but only for fans that are connected via the GPIO pins using the RaPi ‘official’ pins. The idea is that the fan is used to control the CPU temperature with the CPU running at full speed. If the CPU rises too much in temperature with the fan on, then the CPU clock speed will be reduced. This seemed to work well on the RaPi3 I tested it on. It is possible to set trigger temperatures for both the fan and cpu speed independently.

Note that the fan control is simply on/off – there is no attempt at pulse width modulation for finer control.

I believe CJE micros include CPUClock with their RaPis fitted with fans.

Thanks for your tips.

CPUClock is very good. But you need a fan with three wires.
+
-
and one for GPIO 14.

Or, if the fan has only two wires, you can build this circuit.

https://forums.raspberrypi.com/viewtopic.php?t=290383

Use GPIO 14 for Risc OS Pi.

Micky

If you want to control a fan with four wires, then use !FanCon and the EMC2101 Adafruit board.