Image credits and source versions

Basic Watchy face from the source examples ↗ · SQFMI / Watchy contributors · MIT
Seven-segment Watchy face from the source examples ↗ · SQFMI / Watchy contributors · MIT

CAIBI ASSESSMENT

Watchy

CAIBI VERDICTBUILD FOR THE EXPERIENCE

A fully open-source ESP32-S3 e-paper watch sold as a small assembly kit and designed to be reprogrammed, modified and recased.

See what the build involves Original source ↗

Build or buy?

Compare the documented build with the purchase reference.

Build it yourself

Build estimate£45.49Source estimate · high confidenceOne Watchy kit

Time: ~1 hour assembly and setup
Difficulty: 2/5
Physical processes: ESP32-S3 · Arduino IDE

See build requirements →

Purchase reference

Buy price referencePrice not checkedNo priced alternative recorded

Check the source for the exact model, availability and what is included.

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Purchase comparison not yet priced

What the prices cover

Checked regional kit prices already recorded in the assessment.

Includes: Watchy kit.

Not included: Shipping; Alternative straps/cases; Development computer.

Build evidence recorded 4 Sep 2026. Currency conversions are approximate.

The current regional kit prices are useful build costs, but comparing them with an ordinary smartwatch would ignore the open hardware and programmable purpose of the project.

BUILD AT A GLANCE

Source view and main parts

Check the source ↗

**Basic Watchy face from the source examples**SQFMI / Watchy contributors · MITSource and version ↗

Watchy · SQFMI ↗

PHYSICAL BUILD7 key parts or groups

No.	Source specification
01	Watchy PCB v3 with ESP32-S3FN8
02	1.54 inch 200 x 200 e-paper display
03	3.7 V 200 mAh LiPo battery
04	BMA423 three-axis accelerometer
05	Vibration motor and four physical buttons
06	Plastic enclosure and watch strap from the current kit
07	USB data cable and computer with Arduino IDE for custom firmware

Full source specifications

Watchy PCB v3 with ESP32-S3FN8
1.54 inch 200 x 200 e-paper display
3.7 V 200 mAh LiPo battery
BMA423 three-axis accelerometer
Vibration motor and four physical buttons
Plastic enclosure and watch strap from the current kit
USB data cable and computer with Arduino IDE for custom firmware

TOOLS / PROCESSES2 involved

ESP32-S3
Arduino IDE

The real-world work

YOU STILL HAVE TOThe real-world work

Connect display and battery
Assemble case
Enter bootloader mode
Flash and verify firmware
Protect and wear the hardware

THE BUILD SEQUENCE

How it comes together

1Preparation

Inspect and test the kit before enclosing it
Check the PCB and parts for damage before assembly. The official guide specifically warns that the glass display can crack if bent and that the battery connector area should be handled carefully.
YOU
Connect the e-paper display
Feed the ribbon through the PCB slot, unlock the small FPC connector, insert the cable with the contacts in the documented orientation and lock it again. Builder reports consistently identify this as the fiddliest physical step.
YOU

2Build and assembly

Connect the battery and prove the stock watch
Connect the battery, charge over USB and confirm the menu, buttons and clock update before closing the enclosure. Do not force the case if the battery cable, buttons or display are misaligned.
YOU
Install the Watchy development environment
Install current ESP32 support and the Watchy library in Arduino IDE, then select the ESP32-S3 settings documented for v3 hardware. AI can help diagnose dependency or serial-port issues but should not guess the hardware revision.
AI + YOU

3Configure and test

Enter bootloader mode and flash a known example
Use the documented button sequence to expose the ESP32-S3 serial port, flash a stock example or watch face and reset the watch. Proving a known example separates toolchain problems from custom-code problems.
AI + YOU
Customise without destroying battery life
Change watch faces, data sources, controls or features after the baseline is stable. Keep Wi-Fi, Bluetooth and wake frequency deliberate because the official battery guidance shows radio use can cut runtime substantially.
AI + YOU

Benchmark this project

Use the Watchy prompt. Compare what different models deliver, then add what happened when you tried it.

Try this benchmark

View the project prompt

CAIBI adaptation · Prompt 1.0 · Project source

Prompt for Watchy

CAIBI project benchmark: Watchy
Prompt version 1.0

Help me build Watchy using the existing creator project at https://github.com/sqfmi/Watchy. This is a CAIBI benchmark adaptation of the project build brief, not a claim about how the creator used AI.

Project context:
- A fully open-source ESP32-S3 e-paper watch sold as a small assembly kit and designed to be reprogrammed, modified and recased.
- Build context: Watchy PCB v3 with ESP32-S3FN8; 1.54 inch 200 x 200 e-paper display; 3.7 V 200 mAh LiPo battery; BMA423 three-axis accelerometer; Vibration motor and four physical buttons; Plastic enclosure and watch strap from the current kit; USB data cable and computer with Arduino IDE for custom firmware.
- Where AI helps: Watch-face code, Firmware changes, ESP32 troubleshooting, Power-use optimisation, Custom feature planning.
- Physical work: Connect display and battery, Assemble case, Enter bootloader mode, Flash and verify firmware, Protect and wear the hardware.
- Main limitation: Assembly is simple but the glass e-paper display and tiny ribbon connector need care. The stock experience is also deliberately basic, so much of the value depends on wanting to customise the firmware rather than simply wear a finished smartwatch.

Read the source first. Use its published design, files, dimensions and parts as the baseline; do not redesign it unless a missing detail requires a clearly labelled proposal. If you cannot access a source or verify a revision, say so.

Provide one practical build package:
1. Design and files: explain the source design, link the original editable files, and identify missing files or modifications.
2. Parts and fabrication: give quantities, exact variants and compatibility, plus a cutting or printing list where applicable. Preserve source dimensions; flag anything unconfirmed.
3. UK and US purchasing: direct product links, checked dates, stock, pack sizes, taxes, delivery and regional costs. Mark unverifiable details as unknown; do not invent links, prices or availability.
4. Assembly: an ordered guide covering fabrication, fitting, wiring or software as applicable, setup, checks and troubleshooting.
5. Cost and time: separate parts, fabrication, delivery, hands-on time and machine time, with assumptions and exclusions.
6. Function and ease: a test plan for the project's stated purpose, likely difficulties, required skills and any corrections or limitations.

Keep source facts, your proposals and items needing physical verification distinct. An estimate is not a measured build result. Do not claim to have built or tested hardware. Include failed attempts and omissions. If a section does not apply, say why.

Use the source as accessed during this run and record its revision or access date. The prompt is fixed; the linked source can change.

Open and copy prompt →

Benchmark results 0

No reviewed results yet for Watchy. Add the first result →

AI IN THIS PROJECT

Get AI help on this build

CAIBI · AI CAN HELP

AI can help with

Watch-face code
Firmware changes
ESP32 troubleshooting
Power-use optimisation
Custom feature planning

CAIBI · AI CAN'T DO

You still need to

Connect display and battery
Assemble case
Enter bootloader mode
Flash and verify firmware
Protect and wear the hardware

Original source AI use and prompts

SOURCEThe original project does not publish an AI prompt

The prompts below are CAIBI helpers for this build. They are not presented as instructions from the creator.

CAIBI STARTING PROMPTS

Copy a prompt for this build

Each prompt tells AI to keep the original project source as the reference and to flag anything you must verify on the real build.

Ways to take it further

AFTER THE FIRST BUILD

Ways to take it further

Custom watch facesAlternative firmware3D printed case using published STEP/STL modelsCNC aluminium caseCustom network dataDifferent wake schedules and power strategies

More routes and resources

OTHER WAYS TO GET THERE

You do not have to follow one route.

ORIGINAL BUILDFollow the creator route

Use the published files and instructions as the baseline.

REVIEWED RESOURCES

Useful places beyond the main source

GITHUB REPOWatchy

Canonical firmware and Arduino library repository for the open-source watch, with current release history and examples.

DOCSWatchy v3 hardware reference

Official revision table, v3 ESP32-S3 hardware details, battery specification, dimensions and hardware design-file links.

DOCSWatchy assembly and firmware setup

Current official assembly, bootloader, Arduino and firmware-upload route for v3 hardware.

DOCSWatchy battery guidance

Official runtime expectations and the specific Wi-Fi, Bluetooth, display and deep-sleep behaviours that affect battery life.

COMMUNITYIndependent Watchy build report

Independent build and firmware experience reporting simple but fiddly assembly and more friction around flashing and the software toolchain.

COMMUNITYIndependent Watchy first impressions

Independent ownership report supporting the learning-platform case while flagging exposed-screen and form-factor compromises.

SOURCE · CAIBI · BUILDERS

What supports the verdict

SOURCESQFMI

Current Watchy documentation covers v3 hardware, assembly, Arduino setup, battery behaviour, replacement parts and open-source files. Independent builder reports corroborate the easy-but-fiddly assembly and the value of the platform for firmware experimentation.

Open source ↗

CAIBIBUILD FOR THE EXPERIENCE

The reason to choose Watchy is not to beat a mainstream smartwatch on features. It is to own an unusually open wearable platform whose hardware, firmware, watch faces and enclosure can all be changed.

Evidence: Strong

BUILDERSNo published reports yet

Actual time, cost, changes and outcomes appear here after submitted builds are reviewed.

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HAVE YOU MADE THIS?

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First-hand evidence improves the assessment

What we want to know

What happened when you actually tried to make it.

Did it work?
Actual time and cost
What did you change?
What was harder than the source suggested?
Would you build it again?