I build mine from scratch, including the PCB and a 3D printed case.
For sure, that's not at all the same level of customability, programmability, capacity, nor quality. But It is really a DIY one.
For anyone interested: https://github.com/jblezoray/hpdl1414-watch
1. O2 monitoring. I have sleep apnea and live at high altitude, so this matters to me.
2. Motion sensor. Also mostly for tracking sleep.
3. Vibrator for notifications.
4. A screen backlight.
5. Battery life longer than a week.
6. Waterproof enough to survive a splash in the shower/rain.
I consider GPS, cellular, AI, touchscreens, cloud-only sync and control apps, and just about everything else to be anti-features. There are no devices that really cover all this that I've found. A few Garmin and Amazfit/Zepp devices come close, but they have enough drawbacks for me to not be happy with them. The new Pebble is nearly perfect, but the lack of an O2 sensor is a dealbreaker for me :(
Ofc, im excluding apple
Regular DYI watches aren't big news...
(I would be over the moon for a DIY smartwatch with zero AI and e-ink screen.)
not sure if it will happen this decade but definitely next decade
proper running/cycling metrics are hard as demonstrated by how many well-funded competitors are somewhat close but not there 100% yet (Coros, Amazfit, etc)
someone once hacked and decompiled older Garmins but newer ones are encrypted/signed/locked-down
The Ollee watch circuit board [2] is similar, better backlight but closed-source firmware and configuration over BLE in a smartphone app. Still no notifications over BLE though.
I'd think combining 1 and 6 (O₂ monitoring and waterproofing) would be difficult.
I have a garmin watch and didn't know this.
That said, I just used it out of the box, and never (on purpose) hooked it to wifi, bluetooth, garmin connect, etc. Can't do that with an apple watch.
I love(d) my bangle.js. Such a true hacker device. Really fun to use WebUSB and push JavaScript files as apps.
But the GPS on that device was a mess, honestly. I know this is a complicated problem but having to synchronize to satellites and recalibrate all the time was beyond me.
I really wanted it to work because I built my own toy run tracker visualization tool.
I am curious about this new lilygo device because it sounds like it has an alternative location sensor: "A u-blox MIA-M10Q GNSS module provides accurate location tracking..."
I'll need to look that up. Anyone have a summary on what's the difference between that and regular GPS?
1990s is going way back though, they didn't even have mass-storage mode then, it was their proprietary "garmin mode" for usb which only things like BaseCamp can talk to
It's amazing that the market is big enough to get the price that low.
[1] https://www.amazon.com/LILYGO-T-Watch-S3-Development-SX1280-...
DIY analogy would probably be about acquiring individual gears
a pixel watch 4 says they last 30 hours , ambiguously. they use a battery less than half the size. in reality with constant use they'll drop dead in 6 hours.
the thing is clunky and heavy , anyway -- so if it lasts as long as an off the shelf watch who cares?
also, the primary reason : lilygo shoves ESPs into everything.
imagine breaking a $3 watch that is not quite as indestructible as people think it is, but it is nonetheless pretty robust, and then trying to shove something 100x glitchier and 5x as expensive into its case...
They had a segment of customers who wouldn't have or be allowed to connect a phone - triathletes, long-distance hikers, military. But it's been slowly changing as users want more modern features and the company wants to increase sales.
Furthermore, bugs. To this time there’s random crashes that happen with sleep which limits their use
https://imgur.com/a/diy-automatic-e-ink-newspaper-using-rust...
After careful optimization, the v1 got about 6 months out of a 1100 mAh battery. Later improvements and bumping to a 3300 mAh battery got me to 14 months, before my kid yanked it off the wall, total'd the panel and I rebuilt it. The test continues.
That said--op isn't wrong. If power usage is the metric you optimize for, there's much better BOM than an esp32.
Driven by a desire to break free from walled gardens, many hardware hackers have designed their own smartwatches. Instead of proprietary hardware and software platforms, these devices typically use highly accessible components like ESP32 microcontrollers and custom-built firmware. So far, so good; however, commercial smartwatches still beat them in one very important way — durability. DIY solutions don’t hold up well (or at all) to the conditions — like rain — that we regularly run into in our everyday lives. This factor alone makes homebrew smartwatches more of a toy than anything practical.
But now, there is a new smartwatch developed by LILYGO called the T-Watch Ultra. It’s got about everything you would expect from a smartwatch (and a few extras) included onboard, and it can be programmed using common development platforms such as Arduino IDE and ESP-IDF. Beyond its internal specifications, the T-Watch Ultra is housed in an IP65-rated case, so you don’t need to be concerned about rain, spills, or dust while you are wearing it.
An overview of the features (📷: LILYGO)
At the core of the device is an ESP32-S3 from Espressif Systems, featuring a dual-core Tensilica LX7 CPU running at up to 240 MHz. With 16MB of flash and 8MB of PSRAM, the watch has significantly more memory than many hobbyist wearables, making it suitable for more complex applications, including edge AI tasks. The inclusion of vector instructions for AI acceleration further supports this functionality.
The display is a 2.01-inch AMOLED panel with a sharp 410×502 resolution and full capacitive touch support. Combined with a 1,100mAh battery — an upgrade over earlier models — this provides both improved usability and longer runtime.
In addition to Wi-Fi and Bluetooth 5.0 LE, the watch includes a Semtech SX1262 LoRa transceiver, enabling long-range, low-power communication. This opens the door to applications like Meshtastic nodes and off-grid messaging systems — capabilities rarely seen in smartwatches.
What's in the box (📷: LILYGO)
A u-blox MIA-M10Q GNSS module provides accurate location tracking, while a Bosch BHI260AP smart sensor enables motion-based AI features. Additional hardware includes NFC via an ST25R3916 chip, a real-time clock, a vibration motor driven by a DRV2605 controller, and a microSD card slot for expanded storage.
Audio support is handled through a built-in microphone and a MAX98357A amplifier, and power management is overseen by an AXP2101 PMU. The device also features a USB Type-C port for charging and programming, making development workflows straightforward.
With support for Arduino, MicroPython, and ESP-IDF — and an ecosystem of example code and libraries — the T-Watch Ultra makes development easy. LILYGO is now taking pre-orders for $78.32, and the device should be available any day.
R&D, creativity, and building the next big thing you never knew you wanted are my specialties.