visitor@locket:~$

Locket

“a quiet cosmos I carry in my pocket.”

A whole AI chat terminal that fits in your pocket. It runs on a Hack Club Sprig — no phone, no computer. You type on 8 buttons, it answers over WiFi, and the reply streams onto the little screen. All software, all Rust.

▶ Watch it work Build your own

Rust
no_std
Embassy
WiFi streaming
8 buttons

drag to spin · 3D model © Hack Club · MIT

# see it run

Typed on 8 buttons, answered over WiFi. The name? It's the first line it ever wrote me: “a library shrunken to a locket of light.”

# what it does

Talks to an AI over WiFi with the whole conversation remembered, streaming live to the 160×128 screen.
Switch providers on the device — OpenRouter, or Hack Club AI (free) — plus model switching.
Types on just 8 buttons with a two-stage keyboard and word prediction, so you grab whole words instead of tapping every letter.
Three themes you flip between — phosphor terminal, modern dark, and Game Boy. (This site has them too. Try the buttons up top.)
Plays AI games — a text adventure, 20 Questions, trivia.
Types into your PC over USB, like a tiny keyboard.
Remembers everything — settings and your last chat survive a power-off.

# build your own

Your WiFi and API key get compiled in, so you build your own copy. About fifteen minutes the first time — mostly the computer compiling while you grab a drink.

Get the tools (once)

Install Rust, then add the chip Locket uses and the flashing tool:
```
rustup target add thumbv6m-none-eabi
cargo install elf2uf2-rs
```

Grab the code

git clone https://github.com/Swamstick911/Locket.git
cd Locket

Add your details

Copy the example config (the real one is gitignored, so your keys never get pushed):
```
cp firmware/src/config.example.rs firmware/src/config.rs
```
Open config.rs and fill in your 2.4 GHz WiFi, plus a key + model for a provider — OpenRouter or Hack Club AI (free).
Build & flash

Build it, then hold BOOTSEL while plugging in the board (a RPI-RP2 drive appears), make the .uf2, and drop it on that drive:
```
cd firmware
cargo build --release
elf2uf2-rs target/thumbv6m-none-eabi/release/sprig-llm-firmware sprig.uf2
```
It reboots itself and you're in. Power it from any USB plug or a power bank afterward.

# using it

tap, tap

Type a letter: tap its group, then the letter.

I / J / K

On the letter screen, the right pad grabs a whole predicted word.

Space — or accept the highlighted word.

hold L

Action menu: send, expand-with-AI, backspace, settings…

in a reply

Scroll with up/down, or send it to your PC over USB.

# talk to it

This whole site runs on terminal energy, so — type a command. Start with help.

locket@web:~$