I’ve always loved the idea of a hacker girl with a computer strapped to her wrist. This is a theme of Ember’s Sonata (working title), where the protagonist, Ember, wears a wristbound device called a Dreamcatcher [sic]. When I created that device and the character model, I wanted to get the proportions right, so I measured my own wrist and used it to create the model.
Fast forward several years to summer 2025, where I was working multiple simultaneous technically involved contracts and doing IT house calls for the townsfolk as a side hustle. Smartphones are nice and all, but what I really needed was something I could have on my wrist and write commands into on the fly.
Luckily for me, I already had a model that I knew would fit me. All I needed to do was modify it for real world hardware. I call the result a Dreamcatcher Alpha, because it’s a real world version of a fictional design (the Dreamcatcher).
The first build:
Mainboard: Raspberry Pi Zero 2 W
The Zero 2 W holds a stunning 1GHZ Quad-core, 512MB Ram, and a VideoCoreIV GPU. It is not as powerful as a smartphone, but it is a lot smaller than a smartphone. It also has a premade Kali 2025 OS ready to go for it. It should be powerful enough for my purposes. I’m not gaming, after all.
Display: HyperPixel 4 Rectangular
The HyperPixel4 is a 480×800 display that has two special properties that make it perfect for this build — it fits directly on to the pi’s breakout pins, and it is crucially only 2.3″ wide. I might be tall, but my wrists do not seem to have gotten the memo, so under 2.5″ is critical for the device to be wearable.
Frame: 3D Printed PLA
It took me a few iterations to get a frame that fit everything in and lined up with the fittings on the HyperPixel. The frame needed to not only protect the display, it also needed strap holes. I placed two on one side (the one with the USB out), and one on the other.
Strap: Scavenged
I needed a strap capable of handling a lot of stress, so I chose some high density lea– kidding. I cut the strap off a damaged life jacket and sewed a wrist strap from it. It works great.
Iterations:
For the initial hardware build, I used Raspberry Pi OS instead of Kali. I knew that getting drivers working well in Kali would not be trivial, so I chose to start with a compatible OS. Once I had the hardware working, I would get the software working.
Step 1. Get the display and the PI working together.
This part was easy. Square shape in the square hole. Plug the HyperPixel into the Pi (physically, it’s more the other way around, considering the screen is much larger!).
Step 2. Get the Pi to show the display.
The good news is that Pi (and Kali) technically has a driver builtin to use the display. This part is easy in theory – flash the OS, then follow the instructions over at the Hyperpixel4 driver’s github page.
https://github.com/pimoroni/hyperpixel4
Done. Right? Well… no. As I found out the hard way, those are the old instructions. After several attempts and a broken SD card, I eventually found out that the correct instructions are now here. Joke’s on me for not looking at the issues page before installing.
https://github.com/pimoroni/hyperpixel4/issues/177
After doing it the correct (and considerably easier) way, I had a display working. Now I had to get it into the frame.
Step 3. The frame
I went through a few rejects before I had a frame that fit properly. My first frame was too short because I had accidentally switched the calipers from mm to inches in a measurement (making it too tall).
The second iteration fit the screen fine, but I made the mistake of designing it around the idea of inserting the pi and screen separately, and ended up busting another SD card. Those things are delicate!
The third iteration had too small of a slot for the micro-usb slot, making it impossible to power.
The fourth time was a charm. IT is imperfect and by far not final, but the fourth iteration was good enough to keep the screen safe and stay snug. The first test was with zip ties.
Once I had the screen working with zip ties, I needed one final ingredient. A strap. Thankfully, living on Little Cranberry, finding a strap is pretty easy thanks to discarded life jackets. I cut a section of the strap off and removed both sides of the plastic clasp, then re-sewed the female clasp into a smaller strap. I attached the male end so that it could slide, and it was good enough.
It’s ugly, dorky, and I love it. Plus, when combined with an opera glove, it does look cyberpunk in a primitive kind of way!
The hardware was the easy part. The hard part comes next — getting the display to play nicely with Kali. But that is a story for another day.