Part of the fun of playing with Raspberry Pi Zeroes is that their tiny size means they can be fitted into an amazing variety of cases/enclosures and unusual spaces.
This is a summary of the various cases I've tried for my Pi Zeroes, both intentional cases and things I've just tried out, with a bit of amateur bodging.
I've also noted some of the basic considerations when picking a case, mainly to help myself remember what to think about when hunting for a good case. If any of the notes get too long and waffly, I'll give that case a separate page.
These are the various Pi Zero cases I'm currently using or have tried using on past projects. Most worked to some degree, although not always as well as I hoped.
First up, possibly the most popular case I've seen, this laser cut rainbow case from the nice guys down the road from me - Pimoroni. There's quite a lot of info around t'web and on Pimoroni's site about the various flavours available. The one I have is this one.
Basically it's a lovely simple case, easy to assemble, nice and cheery and robust. I have a little internet monitor widget that uses this case, sat next to my desk, with a Blinkt and a sheet of card wedged behind it, telling me what the colours mean.
One thing to note about this case is that one of the middle layers is designed to fit very closely around the components on the Pi, so you should make sure to get the one that matches your Pi version.
The plastic itself is fairly soft, so if you do need to do a bit of surgery due to variant mismatches, a sharp knife and a steady hand will do the job.
My first attempt at using some other tiny case and modifying it to fit a Pi Zero. These cases cost a few quid from Amazon or similar. They're just big enough to fit a Zero, tiny wifi dongle and maybe a very tiny USB hub.
I was quite happy with the size and shape, everything just fitted, especially with a bit of bluetack to hold stuff in place. To power it I drilled a hole right by the hinge and fitted a very short micro-usb to female usb adapter cable, so that when closed the device just exposed a USB socket on a short cable, for power.
The downside became obvious when I powered it up and tried to use it as a neat little local wifi webserver. Yes, as you've probably realised, that's basically a little metal box, with a wireless antenna inside it. Which doesn't work very well. Or at all. Doh!
However, the form factor is very neat, so although I've abandoned the idea for now I may come back and see if there's some way to get a wifi signal thru the case without spoiling the neat look. Alternatively I may go for a tiny oled/e-ink screen, to make a device that turns on when you open it, making use of the clamshell to hold the screen in one half and the gubbins in the other. The wifi works fine when the case is open.
Lesson learnt: Don't use full metal enclosure for a project that will have a wireless antennae (Wifi, Bluetooth, ZigBee, LoRa, etc) inside the box. Radio doesn't like going through solid metal boxes.
This is very similar to the Pibow, but using mainly wooden layers. Unfortunately the one I got, while it was discounted, was also not very well cut. The dimensions were slightly out (holes don't all line up, the SD card rebate is a bit off centre) and the finish was quite rough. However, a little time with some files and sandpaper did the job and it's a perfectly servicable case now.
Pimoroni also dabbled with a wooden version of their Pibow, but stopped after a short time, so maybe doing accurate and well finished cutting of wood for electronics at a cheap price is just one of those things that's very hard to do.
Probably my favorite "found" case so far, mainly because it's such a close fit and meant doing some fairly cunning (for me!) soldering on the backside of the Pi to get the power and wifi dongle to fit. Also the end result is very pretty with the Unicorn pHat doing its thing while the jar is stood on its lid looking like some old school thermionic valve.
This has become a fixture on my desk now. It's running a little Python script which scans a few aspects of various servers and network devices and displays pretty colours to indicate how healthy they are.
The main problem I've found is that the LEDs on the Unicorn pHat are so bright that I've had to sand the glass jar to diffuse them a bit, and also update the scanning script to dim the LEDs as it gets darker. The script also turns off the LEDs when it's time for me to go to sleep - keeps scanning and logging, just doesn't turn on the LEDs until morning.
I'd recommend keeping an eye out for little glass jars, they work amazingly well for pretty indicator type projects.
Of course, once I found the Sainsbury's spice jars were a good fit, they changed their design! Hunting around for a replacement turned up the 170g size of Coleman's mustard (the bright yellow proper stuff, none of this continental or American nonsense ;-) ). These are even a little easier to work with because the mouth is a bit wider and the lids are simpler.
I don't yet have a live project in one yet, but I have checked all the bits for size, so a Pi Zero, wifi dongle, Piglow and OnOff shim do all fit in the jar, with a flat USB cable sticking out of the OnOff shim and through a trimmed hole in the side of the lid.
So I bought a cheak little "Jewelery box" off Ebay for a couple of quid, which had the right width and length to neatly house a Zero with a little battery pack, LCD display, wifi dongle, and a Skywriter hat. The trouble is, I didn't check the height. This thing could fit at least 5 of the same project in it! The components I had in mind actually fit into just the flip top lid of the box!
Ah well, lesson learnt and I have a neat box to keep a bunch of components in for any future projects.
Lesson learnt: Adam, this is a reminder - check all the dimensions when buying a box.
The small flat square boxes used for delivering new Pi widgets work very well themselves as project boxes. They're easy to cut holes in for cables, wifi antennae, buttons, etc. They're easy to open and close to fiddle with the kit, and they're fairly robust against accidental knocks.
If you're not sure what case to use for a project, you could do a lot worse than start by sticking everything in a small cardboard box while you prototype it.
These are just some general things I think about when picking enclosures for any kind of project, not just Pis. If you're an industrial designer of an kind, feel free to rant about how little I know about this stuff!
I will almost always need to get at least one cable into the device. Even using a battery - at some point it'll need charging. That means either a case that can be opened a lot, or a power port. Yes, wireless charging exists. But for now, for a Pi, it appears to be quite slow, unreliable, and expensive.
If there's any kind of sensors or wires off to other things, running wires through a hole cut in the case means considering where those holes should be, how to make them and how to protect them. Maybe a grommit, maybe some strain relief is a good idea.
For any kind of long term project, we're talking proper sockets rather than just holes in the case, flappy cables, cable ties and tape.
It's gonna need some electrical power. Preferrably 5-ish volts, one or more amps and very little variation (Pi's seem sulk if you give them a wobbly power supply).
Although the Zero doesn't kick out much heat, that 5-ish volts and 1-ish amps means there's about 5W of heat to be dumped somewhere. Preferrably into some air which can go away.
If you're using a sealed (or nearly sealed) case, you may need to dump the heat into the surroundings by something cleverer than just air. Maybe a metal case, heatpipe, heat-exchanger construction? Maybe a peltier module?
Actually, in practice it appears that even when running a Pi Zero with a Unicorn pHat flashing its lights 24/7 in a small glass jar, in the middle of a hot summer, the core temperature stays remarkably low (less than 50C most of the time). So cooling probably isn't an issue for most uses.
Even if the device is going to just sit on a desk, it'll need some kind of protection from mugs of tea, dropped screwdrivers, wildly flailing elbows, general ineptness (or is it just me?)
If the conditions will be any way harsh (left outside, stuck in a bag, strapped to a dog, taped to a rocket, whatever) protection is likely to be the main consideration here.
How are all the components going to fit inside the case? Will they just friction fit due to picking the right size case and pushing a bit? Or does that mean you're cramming too hard and are going to break things?
If the case is a bit bigger, there may need to be padding/stand-offs of some kind, maybe a bit of bent card will do the trick, or maybe something more substantial. A 3D printer obviously opens up a whole new world for this side of things, whether it's making the whole case or making little inserts for use with other cases.
I just made that up, but it's a consideration related to all the considerations above. Basically, how easy will it be to modify the case to do the job? Can I cut it with a sharp knife (e.g. cardboard, thin PE plastic), or will it need a dremel? Can it be sandpapered to shape or smooth it? Can I drill holes through it? Or is it a "take it or leave it" situation?
Pretty much all the projects I've played with include some kind of indicating lights. It's best if they can be seen. Some of them are bright enough to be seen through thin card or opaque plastic. That does mean considering whether the covering material will get warm, but in practice I've found that as long as there's some air between the LEDs and the covering, heat hasn't been a problem.
If your project doesn't have any blinkenlights - go on, add some! Even if it'll be stuffed away in the attic or garage, at some point you'll want to take a peek to see if it's still working.