A programmable watch you can actually wear | Hacker News Reader

A programmable watch you can actually wear

hackster.io

231 pointssarusso132 comments

I've loved the idea of a computer on my wrist since I was a kid but now they're available, I find myself unable to think of an actual useful application for them apart from telling the time - what do you smart watch people actually do with them? Are they mainly toys or do they enrich your life in some practical way?

I stopped wearing my Apple Watch because notifications were too distracting when trying to work (even with Work Focus, I want some notifications, but I don’t want my wrist buzzing and lighting up all the time). I don’t miss it. The only real use I ever got was GPS directions when riding a bike or electronic scooter. I guess I also tracked my runs with it. But I don’t use those often enough, and I can wear the watch for those situations if needed.

I do also love the idea, though. I think part of the limiting factor is that you can’t attach sensors or peripherals to it. Even with a hackable watch like in TFA, there’s only so much you could add without it getting bulky. And the screen is too small to do much with.

Same here, loved the idea since I was a kid and I spend a lot more money on gadgets than I probably should but somehow managed to avoid getting a smartwatch because it doesn’t do anything a smartphone does better. I just wear a simple casio solar powered watch I got for about $100 which I never have to charge. I still like the idea of something programmable though, but this watch in OP is a bit too DIY for my tastes.

Smart watches, in general, have a better GPS antenna. I tried running using just my phone's GPS and it's all over the place, completely unusable for that task (it showed me crossing walls, canals, running in circles where I went in a straight line etc.)

Also, a lot of smart watches come with a pulseox, so, you can look up your pulse any time you like :D Not super useful unless you are working out, but there's that.

I switched from Apple Watch to a Garmin Fenix 7, for much longer battery life (advertised as ~14 days, in practice 10-12), durability (they're very tough), better biometrics, and stuff like built-in maps/GPS (I camp/hike/hunt/etc a lot). I just didn't use any watchOS features, and I use an MVNO that doesn't support sim cloning so cellular's a wash. In short even with reduced features I am considering just going back to an old analog Timex Explorer and using a dedicated GPS device, because even the more limited feature set of the Garmin seems like I'm barely using what it's capable of.

Don’t have one capable of it, but listening to music whilst running without a clumsy phone to hold/strap to my arm/put in a silly belt would be awesome.

Yeah, we used to have MP3 players for that - I still have my Sansa Clip+ in a box somewhere...

As a former user of the Sansa Clip, I recommended the Shanling M0 as a modern alternative (they sell a separate case for the clip if you want that). Great audio quality and features, format and Bluetooth codes support.

Thanks, I'll take a look!

Some applications that we use in smartphones are very useful, like the alarm clock. I have begrudgingly adapted to their quirks and privacy implications. I'd rather program my own versions, same for smartwatches.

Alarms I can understand, but that's been a feature of standard watches almost since they were invented I think. I'm looking for something that requires a programmable device to be meaningful and so far the ideas are fairly thin on the ground :-) I get the techy appeal though, and agree wholeheartedly about the value of having total control over a device if possible.

In case you're still reading... standard watches alarms are useless to me. Even regular alarm clocks were not very effective for my kinda morning sleepwalking.

Smartwatches are a godsend: I can set multiple alarms with chosen intervals, volume and ringtones, that never stop and place the phone easily at the right distance.

I could even improve on that and the same could be said of most phone apps. Recording and positioning are the most interesting features if they can be decoupled from big brother's eyes.

Apple Series 3 owner for about 9 years.

1. Notifications. Most useful in noisy environments such as grocery stores, airports, shop floors, or any place you may be wearing hearing protection. Also great while working with your hands, like car work or cooking and directions while driving. It’s best to limit them to the apps that matter, and only when you need them.

2. Biometrics.

However, after this watch finally dies, I don’t think I will be going back. Big reason is smart watches are not stylish at all. For men watches are our only fashion accessory that we can freely wear in all occasions. No matter what band or watch face you use you are stuck with a black square attached to your wrist. Also smart watch battery life is a bit of a bummer, it’s hard to beat self winding or solar powered watches that you never think about changing as long as you wear them.

Yeah the battery life is off-putting for me - watches I had as a kid would last for years on a single battery so I think I have that expectation stuck in my mind. I do like the biometrics angle - something that tracked my health condition and alerted me to any problems would be interesting, but it would have to be fully under my control; I'm not keen on my health data disappearing into who knows what databae.

Garmin smart watches can last weeks on a charge

There are reportedly solar smart watches. I do wish my dumb watch was a tad smarter in that it doesn't get automatic time updates, but that's not impossible even without a phone. I haven't found one that's waterproof, solar, wireless time, and the right price though.

It helps mine runs a bit fast so I'm early to things. If it ran slow I'd probably have replaced it years ago. As is, I'm going on 10 years with barely taking it off my wrist and never charging or replacing a battery, and I'm not the first owner.

Citizen has an Atomic Timekeeping Eco-Drive series of watches that have a 200 meter water resistance. If you like complications see the Promaster Skyhawk A-T.

Sadly I got my current watch for free and it still works. And I don't really get dressed up for stuff. So while yes they certainly do have a series of nice looking watches, I can't justify the purchase at the moment.

I run every day. Started doing it for multiple reasons, some of them being health. The watch tells me my pulse, speed, cadence, calories burned. I doubt the numbers are very accurate, but they are consistent, and, probably, not too far off outside of cases of obvious misreading. It also has a way of collecting some data about swimming (which I don't understand, like what is swolf? I know, I could look it up, but I'm a terrible swimmer, so I don't bother).

For people who like to leave their phone in random places around the house, the watch can help in locating it. You can also almost always turn off the alarm on your phone w/o getting out of bed (provided you sleep with your watch on and the phone's bluetooth didn't decide to randomly disconnect).

All this said, I think that smartphones, in general, provide very marginal utility. A little bit of convenience here and there but nothing groundbreaking. If phones had better GPS antennas and a framework to attach devices like pulseox or sphygmomanometer they'd be preferable to the watch because the display is bigger and the input is (slightly) more convenient.

Yeah fitness tracker is a good one; I'm the opposite with my phone though - I get a ton of utility out of mine, but not things that I think would be improved by shrinking them down onto my wrist.

Lately the only useful thing I get out of it is Auto Unlock my phone when I’m wearing a helmet and gloves.

Biometrics, heart rate and sleep tracking are huge, like 95% of the reason I own a smart watch. It's a sensor, not a UI. Everything else can be done better on a phone.

I turn off notifications (because if I get a message on my watch, what am I going to do with it? watch is basically read-only)

One use that comes up a lot: setting a timer. Being able to ad hoc set timers with your voice is huge - without it, my coffee would get cold, my laundry would stay wet, and my kid would be late because dad got distracted by a HN comment.

They're great for doing phone stuff without pulling your phone out of your pocket and unlocking it. I can check if a notification is important, get GPS directions, snooze alarms, get OTP/2FA codes, or check the weather. None of it it is critical but it's collectively a quality of life improvement.

Just two things for me: telling time, same as yourself, and notifying me that my watch has a text message I might want to attend to. If I could replace the notification feature somehow I’d do that.

I used to use it for running but it performs that job very poorly compared to my $200 Garmin.

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.

What would you suggest instead?

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.

Do you have any info you can share on this recorder? Sounds really interesting!

http://supermechanical.com/pickup Been in production hell thanks to tariffs (wrote a lot about it) but should ship by summer.

For an application using bluetooth low energy, a Nordic NRF52840 turned out to be the winner.

Not the newer more energy efficent nrf54 series?

Ooh I'll take a look! Sometimes I get behind the times because I have to find a favorable dev board.

Most of their lora devices are ESP32.

an esp32 on an 1100mah battery will last years on deep sleep, and about a day with wifi on and in high power modes.

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.

I’ll need to check my notes on power consumption. I’ve spent quite a bit of time trying out different modes and configurations… it’s not great. I would not expect years at all. You gotta be very careful about what has to stay on and off.

Furthermore, bugs. To this time there’s random crashes that happen with sleep which limits their use

I have some relevant experience. I built this a few years ago:

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.

Several Garmin watches last for weeks (24 days full charge, actual 1-2 weeks with heavy gps and fitness tracking), and I struggle to understand why consumers accept anything less. It seems like consumers don't realize what's available.

This. Why would I accept anything else than that?

I think cost is one factor. I have a Vivoactive 4 and I love it but it has a reported battery life of 8 days and I get maybe half that with regular run tracking. I'm guessing the 24 days/1-2 weeks is for a considerably more expensive model.

The Garmin Instinct 2 is around $200 and will last several weeks on a charge even using the GPS regularly. Without GPS use I wouldn't be surprised if it lasted a month.

Galaxy watch 7 (I think) weather here. Also about 30 hours. It's a charge every day thing, but allowing for some forgetfulness. It's not ideal, but it's manageable and certainly functional.

I'm not sure if my Pixel Watch 3 is much more efficient than your 4 or if by "constant use" you literally mean scrolling through it actively for hours at a time, but I only charge mine maybe twice a week. It's on at all times, connected to my phone via Bluetooth and to my Wi-Fi network when I'm home, and I actively manage any push notifications I get from it, but otherwise it seems to idle fairly efficiently.

An advantage of ESP32-S3 could be that it seems possible to run Linux on it.

Not natively. It's not a supported architecture and lacks an MMU. Those who have run Linux on it have done so through a RISC-V emulator or similar.

Hmm... I don't have an ESP32-S3 to test, but looking at one of the esp32s3 linux builds online[1], the binaries are compiled for the xtensa arch. So it does seem to run natively rather than through some kind of emulation. Linux's source does have an arch/xtensa/ directory, so that arch seems to be supported on some level by the kernel. ESP32-S3's docs also mention having an MMU[2], though it's possible it's not sufficiently featureful.

[1] https://github.com/hpsaturn/esp32s3-linux/releases/tag/0.0.4

[2] https://docs.espressif.com/projects/esp-idf/en/stable/esp32s...

Interesting! I've only seen the older projects which probably predate the ESP32-S3. I wonder how usable this is in reality though because you typically can only buy modules with up to 8MB of PSRAM, so you'd have to swap the PSRAM out for higher capacity or manufacture a custom board.

I for one like it is ESP-IDF with FreeRTOS, at least we get some variation.

Would be nice to be able to rely on a bit of the same tooling as other general purpose computing devices.

There are other means to achieve that without Linux monoculture.

Yeah one of the Nordic nRF chips would be nice. But I guess the advantage of ESP is the hobby developer community. It's not going to be as good on battery power but the barrier to entry for people wanting to tinker is really low.

That's more a programmable watch than a DIY one :-)

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

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

The HPDL-1414 appears to be discontinued though still available from some suppliers in varying MOQs and leads.

Ok, we'll make the title say programmable instead.

Love it, especially your choice of digit display. Very nice hack! I'd wear that.

It's cool that the firmware is hackable but I think "DIY" is an imprecise way to describe that.

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.

This is almost $80. The PineTime watch is less than half that price. Obviously the specs are different but that's quite a difference.

Where you can buy pinetine for 40$?

From PineTime.

https://pine64.com/product/pinetime-smartwatch-sealed/

https://pine64.com/product/pinetime-dev-kit/

Both of those products are out of stock.

So is the T-Watch Ultra.

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.

[1]: https://www.sensorwatch.net/

[2]: https://www.olleewatch.com/

The Pro version has a better screen (still segmented but more), RGB LEDs and an infrared sensor.

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...

> I'd think combining 1 and 6 (O₂ monitoring and waterproofing) would be difficult.

By O2 monitoring, they mean "blood oxygen through skin via LEDs" - there's no impact on waterproofing from that (as the Apple Watch demonstrates.)

Fitbit Inspire3 ?

Well as a pebble evangelist I have great news! The heartrate sensor on the PT2 can also do O2 monitoring, they’re planning on implementing it in the future :)

That is excellent news! Looking forward to that :)

A watch some people can actually wear. 49x63x22mm is a bit much for my skinny little hacker wrists.

But with the LoRa I'm tempted to pick up a couple anyway.

You'd barely pick up anything with a lora antenna that small

I would love to see some extra sensors for heartbeat, temperature, blood oxygen and whatever else could be captured by the design.

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?)

It had a Bosch motion sensor with AI abilities it says in the description.

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?

LILYGO site shows pre-orders of all 3 versions are sold out unfortunately.

There's an older "Plus" model available on Amazon.[1] Surprisingly cheap, at US$66. This new model is the "Ultra".

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-...

Too bad it seems to not do health monitoring, my main use case of a watch now is sleep tracking with as long battery life as possible

the same for me, however I can imagine that creating a good sleep analysing software based on the hypothethical HRM and accelerometer is mission impossible. I find the best software is Garmin at the moment of writing, or at least suits me well, and it blocks me from buying any opensource watch, unless I want to have two watches on my hands

When can we finally buy a smartwatch that can keep its (color) display ON during the entire day?

Watches with color memory-in-pixel displays have existed since Pebble.

To add, the current Pebbles are estimated to last 30 days. 10-14 days for the round ones.

September 18, 2020. That's when Apple released their Watch Series 6, which has an always on color display, and enough battery to last all day.

You can also configure PimeTime to have an always-on display, and it should even last more than a day.

>last all day

Is this really the benchmark for a wearable's battery life? A single day?

A Garmin memory-in-pixel eInk (MIP) watch? Lots of choices there, since about 2015. Modern versions (MIP not AMOLED, the category is getting confusing) last about 10 days on a charge.

Genuinely curious: why/what would I ever want to run edge AI on a 1100mAh wearable with a tiny power-optimized embedded SoC? I can't think of a single useful scenario. At this scale, a few ifs/elses will do.

That's awesome. If only it didn't look so tacticool.

Still much to big for my taste.

It should (IMHO) have performance like a ZX spectrum or a c64, bare minimum io. 4-6 buttons and so cheap you have to buy it.

Anyone know what the battery life is likely to be like?

Bad.

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 have a garmin from the late 90s and am saddened by the lack of FOSS software to even sync a new map onto it

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

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

oh bud, mine doesn't even mention USB in the manual. I got the thing for like a dollar at goodwill haha

Have you looked at the specs for the upcoming PineTime Pro [1]?

[1] https://pine64.org/2026/03/28/pinetime_march_2026/

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?

Oh nice, didn't realize they were doing a second one. Loved the original but I took mine rock climbing and cracked it :(

> 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.

The underlying Garmin platform is so old that it predates iPhone/Android. I think you can plug in many Garmins via USB without any special software and simply copy activities and data off the watch.

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.

s/Watch/Smartwatch

Regular DYI watches aren't big news...

(I would be over the moon for a DIY smartwatch with zero AI and e-ink screen.)

I would consider a DIY mechanical/analog watch to be far bigger news/more impressive than a smartwatch.

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.

buying movement is like buying whole PCB

DIY analogy would probably be about acquiring individual gears

Is it different with a smartwatch? You buy the kit, it's not like you solder much as far as I understand.

It's impressive you start with a lathe and make the movement yourself!

Not nearly as impressive as designing and fabricating your own integrated circuits and display!

I thought so too, but after quick research apparently there are kits. For various values of "DIY", I guess...

Sure but buying a movement kit is no different than buying a pcb. Writing code is not impressive any more.

Watchy fits the bill:

https://watchy.sqfmi.com/

I have one, its a bit bulkier than I'd thought it would be, but its a fine piece of timekeeping ..

I had one, broke 2 screens before I gave up wearing it... It's really not meant to be work in daily life, which is sad because an e-paper screen makes a lot of sense on a watch.

IMHO it just needs a better case. The watch itself is fine - the bulky case it comes with, not so great.

Ben 10 is slowly becoming a reality

This does look very cool. Every peripheral one could think of, even LoRA!

That stood out to me, too. Garmin should take a hint.

The peripherals are great until you realize there's a dirth of software to use with them .. like, GPS is fun and everything, but not if all you've got is the coordinates ..

I really love the idea of LoRA in a watch though, so I hope that once this gets shipped, the software makes some leaps and bounds ..

Preorders sold out already!

I doubt if esp32s3's power consumption can be used in real life.

I would buy it if it had wifi. A (decent to wear) watch with wifi would be awesome. Tons of ideas for apps I would build for myself

Ofc, im excluding apple

Oddly, the article didn't mention it - but the watch does have wifi.

The article mentions it as "Wi-Fi" if you were scanning with Ctrl+F.

It's an ESP32, it has wifi.

Yes. Though not all ESP32 variants have wifi.

https://en.wikipedia.org/wiki/ESP32#Features

Now we are talking! This one, in addition to all the other alternatives out there, makes the new Pebble dead on arrival. At least at the current price point.

trun on and trun off

No heart rate sensor

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