Journal · Building in the open

A big screen on a smaller board

PHYLAX PCB v3.0 with the 2.24-inch OLED mounted, two buttons and the STM32 MCU
PHYLAX PCB v3.0 — the large 2.24-inch OLED on a tighter board, with the two buttons and the STM32 MCU.

A screen that's easy to read and a device that stays compact sound like opposites. This week we tried to have both — we fitted the large 2.24-inch OLED onto a modified, smaller PCB.

Two things that pull against each other

A few updates ago we chose a screen big enough to actually read — because on a hardware wallet, the display is where you verify a transaction. But we also found the first case was too big to love. So there's a real tension: a large, easy-to-read screen versus a compact, palm-friendly device. This build is our first proper attempt at getting both at once.

The 2.24-inch on a tighter board

We kept the big, easy-to-read 2.24-inch OLED — readability is the one thing we won't trade away, because a screen you can't read is a transaction you can't verify. Then we redrew the board around it: PCB v3.0 is smaller than the original, trimming the body without shrinking the screen. Bigger where it counts, smaller everywhere else.

Still plenty to test

We'll be honest — this is nowhere near done. Button placement, how it sits in the case, the exact board outline, the fit and feel in the hand: there's a long list still to test and refine. But holding a big, clear screen on a smaller board is a real step in the right direction. One stepping stone toward the goal.

That's how this whole thing gets built — one honest step at a time, in the open. If you'd like to see where it's at in person, we'll have the prototype at Bitcoin Thailand Conference 2026.

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