“Unfortunately the Fan SHIM did not initially work with my RPi 4 with Ubuntu - it seemed to interfere with the boot process - booting from SD card. Remove the Fan SHIM and the OS boots OK. Note also that the Fan SHIM seems to work OK when booting Raspbian.
Following feedback from Pimoroni I got this to work by disabling the UART in one of the config files in /boot/firmware. The relevant config file name seems to be different for different versions of Ubuntu - for me it was syscfg.txt
The code to turn the fan on/off seems to work OK, but I'm not convinced it is a good idea. The electricity to run the fan constantly amounts to £1.05 per year for me. I get the feeling that the thermal stress will be less by running the fan constantly rather than a cycle of allowing the board to heat up and then cooling it down. I have another Pi with an acrylic case and fan built in that runs constantly and was the same price as the fan shim alone - half the price of the Pibow Ninja plus fan shim, so I think this should be a lower price especially if bought together with the case.
It cools really well though in the Ninja case, and excellent rapid responses I get from Pimoroni makes them a preferred place to purchase from.”
Ahoy Nick! Have you tried disabling UART - I believe it's on by default in Ubuntu. Forum thread here > https://forums.pimoroni.com/t/fan-shim-will-not-allow-rpi4-to-boot-solved/12229/8
“Please be mindful that the temp sensitive fan speed header won’t work as that will disable the sound in Picade. They use the same GPIO. Otherwise - really good product”
“I put the Fan Shim on every one of my Pis that are in a cluster, running Ubuntu.
They work fine, and the noise reduction from having continuous fans running to the Fan Shim coming on only when needed is amazing.”
“The fan shim is working wonders on keeping my Raspberry Pi 4B and Sense Hat cool. I installed the background service that automates the fan to only turn on when it starts to get warm, which is awesome.”
“Great cooling system for my RPi4, it's small and fits perfectly inside the case. It works very well, it's quiet, and it is programmable. Perfect.
Great job from Pimoroni.”
