Voice-controlled AI hardware
Voice commandson yourwrist.
Press, speak, and your phone does the rest. Cobalt is a 20 mm board that turns a classic digital watch into a voice remote for your apps and your agents.
633 on the waitlist
The Casio F-91W is shown here only to illustrate compatibility with our board. We make the board, not the watch.
This chip is where the magic happens.
Actual size · 20 mm
Push-to-Talk
Press, speak, release. The microphone only listens at that moment.
A minimalist vintage look
The digital watch you know, on your wrist.
Six months of battery life
On the watch’s coin cell, at twenty commands a day.
Press · Speak · Done
Everyday voice commands.
- Music“Play some jazz”
- Alarm“Wake me up at 7”
- Reminders“Remind me to call Paul at 6 pm”
- Calendar“Dentist on Friday at 2 pm”
- Directions“Take me to the station”
- Notes“Note: new strap colours”
- Messages*“Tell Marie I’m on my way”
- Calls*“Call Mum”
* Android only.
The Casio F-91W is shown here only to illustrate compatibility with our board. We make the board, not the watch.
Inside the watch
A powerful chipin a vintage case.
Voice
A microphone that only listens while you press.
Cobalt Link
The wireless link to your phone, Android and iOS.
Commands
Music, messages, calls, alarms, reminders, calendar, directions.
Buttons
The watch’s buttons: one to talk, two for music and volume.
Interface
The original display keeps the time and the alarms. A discreet light tells you when something is waiting for you.
Technical — The board
More sensors in the same case.
Same outline, same contacts, same coin cell as the original module, plus a microphone, motion sensing, a light, a sound and a wireless link.
All the specifications- Nordic nRF52840
- Arm Cortex-M4F processor
- Cobalt Link
- Antenna of the wireless link
- IMU
- Motion: steps, sleep, gestures
- LED RGB
- Light notifications
- Buzzer
- Alarms and confirmations
- Microphone
- MEMS, only listens while you press
Why we build
Simple on the wrist.Powerful in the pocket.
Cobalt started from one conviction: the most useful computers are the ones that ask the least of us. So we kept the object on the wrist as simple as a digital watch from the 1980s, and put the intelligence where the power already is: the phone in your pocket.
Cobalt is an independent project. It is not affiliated with Casio Computer Co., Ltd. and is not endorsed by Casio. “Casio”, “WR” and “F-91W” are trademarks of their respective owners, named only to indicate that our board is compatible. All original Casio watches used in our modified products are purchased at retail and legally owned before modification.
Read the full Casio noticeLeave your phonein your pocket.
Designed and assembled in France.
The hardware, the firmware and the app.
Our own transmission protocol and an agentic intelligence.
Questions
Frequently asked questions.
About the watch, the app, your data and the project. If an answer is missing, write to us at jean@cobalt-watch.com.
What is Cobalt?
A 20 mm circuit board that replaces the one inside a Casio F-91W digital watch. The watch keeps its case, its screen and its battery. The board adds a microphone: you press a button, you speak, and the app on your phone runs the command or files the note.
Which watch does the board fit?
The Casio F-91W, and only that one for now: the board has the shape of its module. Cobalt is an independent project, not affiliated with Casio (Casio notice).
How do I fit the board?
You unscrew the back of the watch, take out the module, swap the board and close it again. You need a small screwdriver and five to ten minutes. The nine-step tutorial is on the Builders page. You are modifying a watch you own: this ends Casio’s warranty on that watch.
When and where can I buy it?
The board will be sold through a Crowd Supply campaign, opening mid-December 2026 at the earliest. Its price will be given when it opens. To be told, join the waitlist. The ready-made watch is not offered for now.
How long does the battery last?
Up to six months on the watch’s CR2016 coin cell, at twenty voice commands a day. This is an estimate based on the datasheets: we have not been able to measure the current yet. The Research page gives our figures and how we got them.
Is the microphone always listening?
No. It only listens while you hold the button. The rest of the time, it records nothing.
Which phones does it work with?
Android and iPhone. The Cobalt Agent app will come out on Google Play and the App Store. A fuller version, Cobalt Agent Dev, will be installed separately on Android. Both are described on The app page.
Do I need a subscription?
No. The Free plan costs nothing: transcription and the basic commands run on the phone. The Pro and Max plans add stronger models, which run in France. Their prices are still to be set (the plans).
Where does my data go?
With Free, nothing leaves the phone. With Pro, your notes are processed in France by Mistral. With Max, by our agent, in France. The details are in the privacy policy.
Can I link the watch to my own AI agent?
Yes, it is planned in the app: Hermes Agent and OpenClaw first, then Claude Code. The AI agents page says where each agent stands.
Is the project open source?
The watch firmware is published on GitHub under the Apache-2.0 licence, with the reference client of Cobalt Link, the link between the watch and the phone. The app and the hardware will follow.
Who makes Cobalt?
Jean and Joseph, two French engineers. The board is designed and assembled in France. We introduce ourselves on the About page.
I did not find my answer.
Write to us at jean@cobalt-watch.com. To report a security flaw, follow the Security page. For research or a partnership, see the Research page.