Raspi 4

While looking at some Raspberry Pi cases the day before yesterday, I looked at this "case" that comes with a fan that plugs into the GPIO pins, which I found quite interesting, since I had never thought to look at the pinout for the GPIO or to use GPIO to power the fan. I was planning on redoing the wiring yesterday, but my best friend had a day off, so I went to his place instead.

I had a small fan from somewhere (I think it was one of the fans from the old XBox?) that I had set aside for a while, and this morning, I was looking at it to see if I was able to use it instead of an 80mm case fan, and I was definitely able to. I pulled out some parts to begin making a mount for it before I realized that the shroud would make it quite annoying to access the GPIO pins to plug the fan into.

I then looked around to see if there was something I could make a new case out of, and saw the tin that my Tool Logic credit-card sized multi-tool thing came in. While I could have made a full case with it, that would be a lot more work than I was willing to put into it, and so I used the lid, since it was shallow enough to not block any ports; it also had enough leftover space to make it easy to figure out how/where to mount the fan.

After figuring out how to position the Raspi, I made the fan mount with two break-off PCI slot covers, using titanium wire to tie one part together (after drilling the holes to mount the fan), and using a couple wraps of clear tape to hold the other side together.

You can partially see the tape on the bottom joint of the fan mount.

I had actually forgotten to drill the holes to mount the fan bracket to the lid, but I was still able to drill the holes without too much of a problem. The lid gave me a bit of a problem drilling into - since the metal was kinda thin, the hole didn't get drilled out cleanly, but I was able to clean it up enough to where it works. I used two bolts to mount the fan to the bracket and two bolts to mount the bracket to the lid, and while I could have cut most of the excess off of the bolts, I didn't feel like expending the extra energy to do so, since it didn't matter either way.

The leftmost bolt was the most annoying to tighten, since I was just barely able to get a 10mm combination wrench (open end) to hold the nut (I didn't feel like finding an adjustable wrench).

I reused the screws that I used as feet from the old "case", since the heads to the mounting bolts are obviously not flush against the bottom. I also had to cut part of the tin to accommodate the power cord - which is a USB A to mini-B cord with a mini-B to micro-B adapter attached to it. I also trimmed a part of the top ESD foam that wasn't necessary off, wedging it between the bottom ESD foam and the plug opening to kind of hold the plug a bit.

The metal warped, since it was thin, which you can see here.

I had thought I was done, when I realized the board still had a bit of free movement (the ESD foam has permanent dents that partially prevent it from sliding around, which isn't enough to hold it securely. After about half a minute, I remembered that I thought of using another bolt from the fan-mounting hole to hold the board down. The bolt I used was originally quite long, and I was going to use two nuts to position it, but that proved to be very awkward to tighten properly at the correct height, so I just measured and cut it to length instead (which saves me a nut). I used part of the piece I cut from the lid to make a flat surface for the bolt to transfer the pressure onto, and trimmed a bit of the blue rubber to match the size.

"Front" view and holding bolt closeup.

While it works, I'm worried that the stress might cause the fan assembly to crack and break, but I'm hoping that doesn't happen. The airflow is pretty much directly on the SoC and the LAN IC, which will keep it relatively cool, though it's not entirely necessary.

Top view (angled). The angled cut on the bottom ESD foam was to facilitate having it in the corner, but wasn't the best layout.

I think I'll buy another Raspi since the second revision of the B model has mounting holes, which will make it much easier to attach to this "case" and allow me to remove the board-holding bolt. When that happens, I'll get a case to toss this Raspi into and use it for something else.

It took about 5-6 hours to make this "case", but it was worth it, since it's a lot more open and all the ports are a lot more accessible. The only problem is that the "foot" placement wasn't great, so it doesn't stand on the switch properly - oh well.