Overview
Kleidos on the M5Cardputer ADV
Kleidos turns the M5Cardputer ADV into a password manager: it keeps your passwords encrypted on the board and types them into your computer over Bluetooth, after you unlock it on the board itself. The firmware costs nothing and asks for no account. There is nothing to install yet: version 0.1.0 is not released.
The same firmware runs on nine boards, and I recommend none of them over the others: this page is what the Cardputer does with it.
Updated
Kleidos on its own screen
Every recording here is of the Cardputer's own screen, with a demonstration vault on a development build. The same recordings are on the recordings page, beside those of the other boards I have filmed.
Each picture's badge says how I made it, and the legend of the badges explains every kind.
- Live from the device
What each control does
Each row quotes what the Cardputer itself shows for that control: on the pages it shows the first time it starts, or in the bar at the foot of its vault list.
| Control | What the board says it does |
|---|---|
| Enter | “selects and opens” |
| Backspace | “goes back or deletes” |
| fn with ↑ or ↓ | “move through a list” |
| fn with ← or → | “change tab” |
| The letter keys | “type a name to find it” |
- Enter
- What the board says it does: “selects and opens”
- Backspace
- What the board says it does: “goes back or deletes”
- fn with ↑ or ↓
- What the board says it does: “move through a list”
- fn with ← or →
- What the board says it does: “change tab”
- The letter keys
- What the board says it does: “type a name to find it”
I will write a guide to every screen, board by board, once the interface stops changing.
What it holds, and how it keeps time
The vault is the same on every board. What changes with the board is how much it holds, how it keeps time for the one-time codes and where its backups go.
- Chip
- ESP32-S3
- Input
- Keyboard
- Screen
- 240×135
- Case
- 84×54 mm
- Capacity
- 250 credentials, 40 two-factor codes
- Clock
- Internal, drifts through a sleep
- Card slot
- Yes: it writes its own backups
What it draws from its battery
What the Cardputer draws in each state, as the measurements page prints it, with what each state is and how each figure was taken.
-
M5Cardputer ADV
I give no battery estimate for it: nothing on it reads current, and putting the measurement system in its battery wire means taking the board apart. I publish no unlock time for it yet.
- Asleep
- not yet
- Light sleep
- not on this board
- Normal use
- not yet
- Wi-Fi
- not yet
- Bluetooth
- not yet
Deep-sleeps with the chip still powered: its internal clock keeps counting, but drifts.
What it costs
Kleidos costs nothing: there is nothing to buy from the project and no account to make, and the firmware is free software under GPL-3.0-or-later. What you pay for is the board.
- Price
- US$29.90
- Listed by
- M5Stack's own store
- Product code
- K132-ADV
- Read on
- 1 November 2026
That is what the maker's own store asked on the day I read it, before shipping and taxes. Resellers ask their own, and the price moves.
Where the firmware stands
Kleidos is pre-release, at version 0.1.0: there is nothing to install yet, and the roadmap says what is left before the first release.
- Version
- 0.1.0
- To install
- Nothing yet: no release is published
- Hardened build
- In development
I have not had the firmware or the cryptography reviewed by anybody outside the project; the security page says what you can and cannot check.