A hobbyist has built a Raspberry Pi Pico–based peripheral for the Sinclair ZX Spectrum that taps the Z80 bus and watches Spectrum memory writes to display a hardware minimap for Atic Atac—bringing a modern game HUD to an icon from the 1980s.
The ZX Spectrum’s expansion port has never been shy about inviting tinkering. But one new add-on takes that invitation and turns it into something you can feel the moment you see it: a minimap for Atic Atac that’s meant to look like it belongs in a much newer era of gaming.
Happy Little Diodes is using a Pi Pico–based peripheral to pair with the Sinclair ZX Spectrum. The peripheral connects to the Spectrum’s expansion port. where it picks up all the bus signals from the Z80 microprocessor. From there. it uses a latch to capture Spectrum memory writes—watching what’s happening inside the machine as the game runs.
Atic Atac is a particularly good target for this kind of hardware spying. The game’s operation is well known. which means the device can watch for updates to an in-memory variable that contains the game room ID. Once it knows which room is active. the minimap can draw the map with the player centered on the room they’re in. The result is a cleaner, more “21st century” interface element layered directly onto a classic.
It’s also the kind of project that lands well with people who remember both the ZX and Atic Atac when they were new. The add-on isn’t just functional—it feels like a bridge between the old hardware’s limits and what modern microcontrollers can do when you treat retro machines like platforms instead of artifacts.
And while this build is focused on Atic Atac, the logic behind it suggests room to grow. With the same approach, Happy Little Diodes notes it could relatively easily support other games too.
If you don’t already have a Spectrum, there’s a practical comfort baked in: you can “make yourself one.”
For anyone who wants to see how it all comes together, there’s a video demonstrating the Pi Pico peripheral and its minimap behavior.
By the time you picture the player’s location being tracked in real time and reflected back as a minimap, the appeal is hard to miss: it’s the past, upgraded where it matters—right on the screen.
Pi Pico ZX Spectrum Z80 Atic Atac minimap retro gaming hardware microcontroller peripheral
So they’re basically hacking the old game to show a mini map? Neat but also kinda weird.
I don’t even know what a Z80 bus is but it sounds like a lot. If the Spectrum expansion port is always “for tinkering” then why is my tech never like this lol.
Wait, this makes Atic Atac into a “21st century” game HUD… but isn’t the minimap just screen stuff? Like couldn’t they just add it in software on the Spectrum instead of spying on memory writes? Unless the software can’t do it or something idk.
I watched the headline and immediately thought it was gonna be like some Atari thing. Also “make yourself one”?? okay sure, lemme just build a Pi Pico peripheral and connect to the expansion port like it’s a toaster. Retro people are wild.