STUDY TOOLKIT,
NO CLOUD.
Nexo keeps your notes, homework and music on the M5Stack Cardputer — offline-first, always yours.
A tiny ESP32-S3 device with a physical keyboard, paired with an Android and macOS app over Bluetooth Low Energy and Wi-Fi.
Everything lives on the device
Write and edit notes with a real keyboard. They persist on the Cardputer and mirror to the app.
Track subjects, due dates and status, and sync changes between the device and your phone.
Play MP3/WAV from the SD card, with timer alarms and UI sounds through the ES8311 codec.
A NimBLE GATT server with PIN auth and multi-client support — macOS and Android at once.
An optional access point serves a built-in web UI for music upload/download and settings.
Update the firmware over the air, and keep the app current with one-tap self-updates.
A 240×135 pixel interface
Device first, app second
1 · Notes & homework on the go
Type directly on the Cardputer. Everything is saved to on-device flash with atomic writes — no account, no server.
2 · Sync when you're together
Open the app and it reconciles over Bluetooth, merging offline edits with revisions and tombstones.
3 · Move files over Wi-Fi
Flip on the access point to drag in MP3s and manage the SD card from any browser.
4 · Update in place
Flash new firmware over the air, and let the app update itself from GitHub Releases.
Ready to build your own?
Grab the firmware and the companion app. Free and open source under the AGPL-3.0.