I like your hpdl watch better than the LilyGo watch. As a lover of analog and casio watches I can tell you that your watch can soon build you a loyal following in its current form if you only build 3 such watches and put them on Amazon, etc. and price them at 50$. Next batch of 3 you could try at 100$.
Don't worry about glass cover, our local watch repair guy can easily slap one in it
I like a good smart watch and I appreciate open source, but an ESP32 isn't a great pick when low power consumption is important and the device is going to be communicating regularly. I'm surprised LILYGO went that direction in a watch form factor.
Nordic Semi, or maybe ST Micro. I've got an STM32WB on my bench at the moment with sensitive coulomb counting and it looks very promising but without all those radios. Of course with all those radios (ie, if you need LoRa on a watch... which is a design decision I'm also skeptical of) then Nordic has a good track record.
Different use case (environmental data recorder) but our current product uses an STM that turns on an ESP32 (not trusting that sleep mode) when it needs radio, to run on 2 AAs forever.
No mention of battery life? I guess it depends on the software that you run. But it would be nice to have a benchmark for how long it would last in normal watch mode.
There are only a few features I care about in a smartwatch:
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 :(
The Sensor Watch circuit board [1] inside the case of a Casio F91-W / A158W / A159W satisfies 2, 4, 5, and 6. Accelerometer or thermometer available as daughterboard.
Battery life measured in months, if not years. Although the simple LED backlight and the segmented LCD leaves a bit to be desired, and there is no wireless connectivity for notifications. Open source firmware.
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.
my experience with a sensor watch has been terrible.
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...
This device looks capable of a lot of features and possibilities. Unfortunately nothing comes to my mind because I'm not good with diy hardware (once connected raspberry pi zero with led strips). Could someone tell examples of interesting and/or useful projects one can implement with this watch?
Does anyone know if this has an accelerometer? I recently got a nice sports-oriented smartwatch (non-Garmin), to use it mostly for rowing, but it doesn't track the rowing-rate. It should be pretty easy to program one if the watch has accelerometers, but couldn't tell from the spec sheet (maybe that means no?)
To be honest there is not much to it, you buy the movement, put it in a case, and put the hands on it. you can get everything from aliexpress. it's easier and often cheaper to just buy a normal watch if you need one.
have wished for decades now there was an open-source Garmin on the level of Cyanogenmod / LineageOS for Android
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
I'm very excited about this. GPS was the final piece of the puzzle.
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?
not sure if this will help you but there is a neat website that allows you to build free maps for older Garmin models that didn't have them at first like Fenix5
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
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 :(
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.
[1]: https://www.sensorwatch.net/
[2]: https://www.olleewatch.com/
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...
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-...
Regular DYI watches aren't big news...
(I would be over the moon for a DIY smartwatch with zero AI and e-ink screen.)
DIY analogy would probably be about acquiring individual gears
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
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.
[1] https://pine64.org/2026/03/28/pinetime_march_2026/
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?
https://garmin.bbbike.org/
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