Smartwatch 10 Years Ultra-Long Battery Life

Smartwatch wearable, ultra-long life measured in years, no need to recharge.

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Smartwatch wearable, ultra-long life up to 10 years, no need to recharge.

This project is an effort to design a smartwatch wearable with 10 year battery life on a single charge. 

The secondary goals are to learn/advance knowledge low-level design of embedded full stack circuitry and devices for wearables, ultra-low power, maintenance-free, battery powered, wireless, app-driven, and off-the-grid.

Developing a smart watch from scratch would be a great learning experience to advance my knowledge of low-power, self-contained powered devices. Hence, we learn about watches, smart watches and wearables in general by designing one.

This is not a commercial effort. I doubt that we are making anything new per se, however, we are trying to advance the art a lot further than others into the low-power domain.

My background should allow me to filter out the noise and focus on the salient points. My points of view below.


  1. Ultra-long life. Years, if not decades. The last watch you'll ever need.
  2. Maintenance free. Never needed to open and fix anything inside.
  3. Avoid buttons. Buttons open up the watch to maintenance. Dirt. No moving parts. No bolts, no screws, no mechanical parts. Sealed shut. Control via smartphone? Bluetooth?
  4. Tough. Bang it on a rock or use it to crush rocks. Metal, steel? Titanium? Aircraft aluminum?
  5. Under water. Deep ocean depth grade watch.
  6. Solar / RF powered may be in the future? No battery change.
  7. Multiple time zones. Automatic time adjust / set up.
  8. Other features? Compass, altitude, GPS? Atomic clock sync up? Accelerometer? NFC, BLE? What are other watches using?
  9. Sapphire crystal. Seems other watches are big on sapphire. Diamond? Too brittle? Mineral crystal? Acrylic?
  10. Anything else?

Work to do... Please check the logs for daily progress!

  • Accelerometer Integration Follow-up

    VALENTINE3 hours ago 0 comments

    Excellent news. Code works with NRF52. Hardware works with the old R1 version of the PCB. Not easy but no surprises. The real challenge was to integrate with the display to see debugging messages. I know I make it sound easy but I'm really wondering.

    Ready for integration with the fabbed PCB once I get it, somewhere next week.

    Pictures of the setup attached at the end.

  • Accelerometer Integration

    VALENTINEa day ago 0 comments

    Great progress today on accelerometer integration.

    I'm using the development board from STM, as well as a Teensy as a dev test bed.

    Got the single taps, double taps, and axis acceleration, as well as interrupt/wakeup functionality figured out.

    Next is to move to NRF52 and test in the watch.


    Picture is of the test setup.

  • Evolutionary Waterfall Development Model

    VALENTINE3 days ago 0 comments

    For those of you interested in project management (yeah I know, project + management are dirty words for many), we are employing an evolutionary waterfall development model. That said, project management is absolutely crucial in any setting. The alternative is an abandoned project or relegation to the vast graveyard of great but half-baked projects littering the DIY landscape.

    Evolutionary model combines the Iterative and Incremental model of software+hardware development life cycles. Delivering the product is an incremental process over time. It is better for software+hardware products that have their feature sets redefined over the development timeline because of user feedback and other factors such as manufacturability, component availability and/or budget constraints. The Evolutionary Waterfall development model divides the development cycle into smaller, incremental waterfall models in which users are able to get access to the product at the end of each cycle. Feedback is provided by the users on the product for the planning stage of the next cycle and the development team responds, often by changing the product, plan or process. Therefore, the product evolves with time. All conventional project management and development models have the disadvantage that the duration of time from start of the project to the delivery time of a solution is very high. Evolutionary Waterfalls solve this problem!

    Evolutionary Waterfall models suggest breaking down of work into smaller chunks, prioritizing them and then delivering those chunks to the customer one by one. The number of chunks is huge and is the number of deliveries made to the customer. The main advantage is that the customer’s confidence increases as he constantly gets quantifiable goods or services from the beginning of the project to verify and validate his requirements. Thus, the model allows for changing requirements as well as all work is broken down into maintainable work chunks.

    Another advantage of the Evolutionary Waterfall is that at any point in time you have a working product! Yes, it might be a crappy one, and some features are missing, but you do have a working ten-year-on-a-charge smartwatch on your wrist that proves that the original premise is sound and the end product will work!

    Here the situation is complicated by the introduction of hardware dimensions, so combining hardware with software in a development is a nice little challenge.


  • Battery Pack Design Update

    VALENTINE3 days ago 0 comments

    The cold-solder battery design was a failure, in sense that making cold-solder joints is really messy, takes 24 hours for the cold-solder to join mechanically and the joints themselves leak and require extreme dexterity. On top of that the cold-solder is expensive and very hard to work with.

    The solution would be to make spot-welded designs from coin-cell batteries. I have ordered a simple and really cheap spot-welder (it's just a battery with two copper leads and a trigger) and a roll of nickel strips. The upside of the spot-welded design is that I can also design very quickly any arbitrary battery configuration, and the profile is only 100 microns thick. The cold-solder required extra thickness for the silver epoxy, so that's that.

    This will also allow me to start work on the rechargeable battery pack with a solar harvester. That's a separate mini-project, so I keep adding to the list, mais c'est la vie.

    Stay tuned for the battery pack!


  • PCB Alpha Release 3 update / Thanks PCBWay for sponsorhip!

    VALENTINE3 days ago 0 comments

    Alpha Release 3 is done, will take some time to get it but looks promising.


    Big thanks to PCBWay for sponsoring this release! I will post a full review and feedback later once I get the whole thing assembled and tested. PCBWay went out of their way to accommodate the really demanding SMT and budget and we had to work really hard to "meet in the middle". That tiny PCB which is the size of a US quarter dollar cost $300, so that's not a small effort.


    I know some people ask about time. This type of development takes a lot of time, more-so that I'm working alone, and in my spare time off-work. I have a full-time job. As I mentioned, usually this takes a large team of about 10 to 20 people and about a year to develop (say, 10-man-years, 20-m-y on the upper edge of the envelope) in a high-pressure cooker environment. This isn't a typical home-brew DIY project you complete with off-shelf components and a soldering iron. I'm trying to achieve this at a tiny fraction of the time and budget. Realistically, I'll be lucky if I get the Beta release by March '24.


  • Nano / Micro / Milli Amp-Current-Meter

    VALENTINE5 days ago 0 comments

    I spun off the nano-amp-meter as a separate project.

    Enjoy. Cheers!

  • Nano-Amp-meter :: success!

    VALENTINE6 days ago 0 comments

    The nano-amp-meter is here, pictures of unboxing and device. I tested, and referenced against a commercial nano-amp meter, it works, don't have time now to go deeper but it does work when connected to an oscilloscope for a good and accessible transient analysis. Pics/videos later in a split project.

    I'll split this later as a separate project, I got way too much going on now. Also I need to clean up the design and add silk-screen, and make it more user friendly. Right now you need to really know what's going on to use it, might not be very useful for most people.


  • To-Do Items

    VALENTINE6 days ago 0 comments

    Project log.

    List of do-to items:

    1. 1Ah Battery assembly bookend design complete with cold-solder, and wires.

    2. Magnetometer code confirmation / test / POC

    3. Accelerometer code confirmation / test / POC

    4. Case re-design / re-manufacture

    5. Order reed contact switch for R3 assembly

    6. Nano-amp-meter test/integration

    7. Alarm SW finalize

    8. Solar micro-charge/Panasonic rechargeable 2020 combo POC

    9. Buzzer/steel case integration/test feasibility (sealed case problem) for alarms.

    The way this is going, combined with my free available time, this is targeting January 2024 for the Alpha release. This includes R3 and R5 manufacturing and test and integration.


  • Thanks to PCBWay :: PCB Revision #3 progress

    VALENTINE6 days ago 0 comments

    Good news, the R3 of the PCB is in SMT.

    I was approached by PCBWay for sponsorship. I would like to extend my thanks for their sponsoring a fairly expensive piece of hardware to go into the watch. Once the PCB arrives I will post my experience with them. So far the manufacturing has been progressing smoothly.

    Thanks PCBWay!


  • Nano-Amp-meter progress

    VALENTINE6 days ago 0 comments

    The nano-amp-meter will arrive very soon, this will really help create a standalone toolset to measure the power consumption of the smartwatch. Will post more today as the project progresses.

    Stay tuned!

View all 54 project logs

Enjoy this project?



Yaroslav wrote a day ago point

I can't find schematic of the watch. Is it possible to check them?

I'm interested in particular to power line (battery, voltage regulator) and display connection.

  Are you sure? yes | no

VALENTINE wrote a day ago point

Hi there. The schematics are under development, and have not been tested yet. I will consider opening once I get them to work. There is no regulator, the MCU is connected directly to the battery. You can find the display connection schematics here if you read the logs.

  Are you sure? yes | no

Ale o co chodzi wrote 11/29/2023 at 20:31 point

Is possible create a tamagotchi version?

or old fasion clock  pocket? for example with solar panel? or ..... peltier power

What You think about PixelQ screen?

(I dream about small fuzix or linux device with week working time, no sound, bigest as oqo, pocket vaio P or ELLO2 , irda as ethernet  slow cpu , keyboard

but today clock is very good starting point)

  Are you sure? yes | no

VALENTINE wrote 11/29/2023 at 21:17 point

Tamagochi: Yes.

Solar: Yes.

PixelQ screen: Never heard of it. Part number/manufacturer?

Fuzix: Yes.

Please understand those are hypotheticals. I will not be pursuing them.


  Are you sure? yes | no

Ken Yap wrote 11/30/2023 at 00:23 point


  Are you sure? yes | no wrote 11/30/2023 at 11:08 point

clock or tamagotchi with irda and my own code is great idea!

but in my opinion better is OTP system

this is simple generate pseudo random number using time and salt

login to serwer using ssh and your watch

  Are you sure? yes | no

sup wrote 4 days ago point

we waiting ;)

power is very important in mobile project

  Are you sure? yes | no

VALENTINE wrote 11/30/2023 at 15:19 point

Ha, you are talking about the company PixelChi (or was it PixelQi?), oh that brings memories, yeah their office was just a little down from my office across SFO. They don't exist anymore, last thing I heard was 10 years ago they disappeared. They did those ubuntu laptops  with rabbit ears, I had one, that was a piece of art. Great idea though. You can find so many cheap transflective displays nowadays, I'm not sure why you need to go back in time to those. Technology has moved forward so far, there is a reason those old displays disappeared. I'm sure there is some niche market but I just don't see people paying hundreds of dollars for a low-quality/low resolution transflective LCD for a laptop.

Didn't a Taiwanese company acquire the technology? That was so long ago I vaguely remember something like that.

  Are you sure? yes | no

Ale o co chodzi wrote 11/30/2023 at 17:18 point


Yes I talk about this screen.

I have nothing against the new displays. If they consume less power have better contrast in the sun then why not. ;D

It is important that the system allows you to write your own scripts. I see huge popularity of the expensive device precisely because you can write your own script.

  Are you sure? yes | no

VALENTINE wrote 11/30/2023 at 18:17 point

No scripts. This is a fully custom ROM/firmware geared singularly towards low power consumption, with the PCB designed to match the code and vice versa. There is no OS, or scripting, or anything like that. Think low level C code with some assembly here and there. Think of having a CASIO watch, not something running RTOS or whatever, but with all the smart features of a modern smartwatch.

  Are you sure? yes | no

nephrita wrote 11/27/2023 at 14:38 point

Beautiful work!

  Are you sure? yes | no

VALENTINE wrote 11/27/2023 at 14:56 point

Thank you!

  Are you sure? yes | no

Patrick Lepoutre wrote 11/23/2023 at 12:59 point

Nice work. As a pebble watch nostalgic, I really loved the time-line view that showed next events for the day. Could this be implemented? Even with no button? 

  Are you sure? yes | no

VALENTINE wrote 11/23/2023 at 15:10 point

Thank you. I keep hearing about this pebble thing but havent been able to find (havent looked hard either) much information, I guess that was before smartwatches got popular. What are the features? You got a captive audience here, care to elaborate please?

You could implement any controls you want, lack of buttons doesn't mean lack of controls. Next iteration has an IMU (accelerometer/gyro) and a magnetometer, so any 5-d motion could be translated/assigned to action. By 5-d I mean (+/-) X-Y-Z + North-South + Time.

Think double-tap on the right, single-tap on the left, taps on the edges, orientation, etc.


  Are you sure? yes | no

Patrick Lepoutre wrote 11/23/2023 at 20:05 point

I found some screen shots and designs that could help understand. Pebble worked in color and monochrome. Here is the link

  Are you sure? yes | no

VALENTINE wrote 11/24/2023 at 01:22 point

Thank you, checking. There is no guarantee certain action and features are possible due to this watch having from-scratch custom code, there is no rt-os or anything like that. It's coded from scratch with power savings in mind. The hardware is also designed from scratch around power saving, anything consuming more than a few uA is a cut.

  Are you sure? yes | no

Yaroslav wrote 11/22/2023 at 19:18 point

Can you share mfg code of the screen or a datasheet? Thanks!

  Are you sure? yes | no

VALENTINE wrote 11/22/2023 at 19:42 point


  Are you sure? yes | no

Yaroslav wrote 11/22/2023 at 20:38 point

Thanks! Any reason to not choose an epaper? (ghosting, UV degradation, etc..)

  Are you sure? yes | no

VALENTINE wrote 11/22/2023 at 20:44 point

epaper has high power consumption, wrong use case for a watch.

  Are you sure? yes | no

fdufnews wrote 11/14/2023 at 08:45 point

I just discovered this project and it is in my opinion a super exciting one. Battery life is precisely what keeps me from using “smart” watches.

If it works on a mini solar panel, it is even more awesome.

  Are you sure? yes | no

VALENTINE wrote 11/14/2023 at 18:11 point

The mini solar would be a feature to be added once we confirm and test the first design iteration.

  Are you sure? yes | no

Ken Yap wrote 11/13/2023 at 01:12 point

I'm surprised that a certain forum participant hasn't asked you yet if you can run Fuzix or mesh networking on it, since you satisfy the long battery life condition. 🤣

Nonetheless I applaud your goal. If you achieve 10 years, then maybe the battery doesn't have to be chargeable and can be return to depot to change the battery.

  Are you sure? yes | no

VALENTINE wrote 11/13/2023 at 19:24 point


I'm not sure about anyone asking, I'm new to this platform.

Yes, the design could run Fuzix and/or mesh networking. In fact you could run full-scale Doom, with a TFT screen and sound. However, this would immediately drop the battery life from 4000 days to about that of a standard off-the-shelf smartwatch of 3 to 5 days, give or take (I actually did the experiment and the battery died really quickly). Which is the principal problem I'm solving, a smartwatch with 10 years life. Else you could find plenty of other designs, I'm not keen on reinventing the wheel. To paraphrase a well known quote, I want to do something no one else had done before.

The downside is that the firmware is 100% custom from scratch and the hardware I've also designed from scratch with discrete components to solve the battery life. I've already proved that the watch can live 10 years on a single battery, now I'm only slowly adding all the features. The fact that the watch successfully runs on a single calculator photocell, with Bluetooth and graphics kinda proves my point.

In any respect thank you for looking at the project, and commenting, it's interesting. I appreciate any further input you got, as I said, that's why we are here.



  Are you sure? yes | no

Ken Yap wrote 11/13/2023 at 20:50 point

It was just a little dig at that particular member who has Fuzix on the brain. Hang around a bit and you will see their comments on other µC projects.

  Are you sure? yes | no

VALENTINE wrote 11/13/2023 at 22:59 point

I see. Reminds me a little of the Beowulf cluster comments from the late 90s on Slashdot.

  Are you sure? yes | no

trialexhill wrote 11/14/2023 at 03:59 point


  Are you sure? yes | no

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