This goes into the category of “DON’T TRY THIS AT HOME!” but read on if you don’t mind the length.
Yesterday, my son got a RaspberryPI 3 all set up as a server running Dietpi as the OS with mpd, myMPD, NextCloud, and ProFTP installed and running. It was awesome. After getting all the software installed, he noticed that although everything seemed to run snappy and resource usage looked good, the heat started to build up. First I encouraged him to take off the cover from his case. He found a small desk fan that he leaned over the top of the case which cooled it down nicely, but looked like it could easily fall over at any moment.
When I got home last night I remembered that I had 8 case fans from an old project I did 12 years ago where it was cheaper to buy 10 fans than to buy 1 or 2. I said, “Maybe you could research to see if you can use one of these case fans hooked up to the GPIO of the RaspberryPI and use that as a more permanent solution. I don’t care if you ruin the fan when you rewire it there are still 7 more.”
Then my son realized that if he used some jumper wires from his electronics kit he could hook up the fan right away. I did say, “Oh, I noticed these fans are 12V and the RaspberryPI runs on a 5V power supply so maybe this won’t work.” But then we decided that the fan would just turn at a lower speed because of less power, so he hooked it up, the fan started turning plenty fast as you can see from the picture, but when he rebooted, the PI it didn’t boot back up. He disconnected the fan, and the PI rebooted and everything worked again, so he thought he didn’t wait long enough. He shutdown and reconnected the fan, and the PI didn’t boot. Disconnected the fan, and the PI didn’t boot at all the fourth time.
Those of you who understand electricity better than us, probably realize what happened. We think (after doing some research which we should have done first) hooking up the 12V fan to the GPIO which outputs only 3.3V probably fried one of the fuses on the PI 3 so now we have a dead PI 3.
If you think we can salvage this PI 3 let me know how we can?
If you have some PI 3’s because you have replaced all of your 3’s with 4’s and would like to donate one to our cause let me know?
Otherwise let this be a lesson to learn a little more about electronics before you try what you think will be an awesome idea.
We do have a plan B. I found some old unused wall warts that are DC 12V power supplies for old electronics we don’t have any longer. We are planning to learn to wire one of these to the case fan so it has a separate power supply from the RaspberryPI in the future.
This pic was taken when we both thought this was the best idea ever.