Smartwatch 10 Years Ultra-Long Battery Life

Details

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.

Features:

Ultra-long life. Years, if not decades. The last watch you'll ever need.
Maintenance free. Never needed to open and fix anything inside.
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?
Tough. Bang it on a rock or use it to crush rocks. Metal, steel? Titanium? Aircraft aluminum?
Under water. Deep ocean depth grade watch.
Solar / RF powered may be in the future? No battery change.
Multiple time zones. Automatic time adjust / set up.
Other features? Compass, altitude, GPS? Atomic clock sync up? Accelerometer? NFC, BLE? What are other watches using?
Sapphire crystal. Seems other watches are big on sapphire. Diamond? Too brittle? Mineral crystal? Acrylic?
Anything else?

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

https://hackaday.io/project/193509-smartwatch-10-years-ultra-long-battery-life/log/225387-smartwatch-automata-third-assembly

Project Logs

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Battery life update at 6 months : 10+ years !
VALENTINE • 06/17/2024 at 19:17 • 0 comments

The original pre-alpha version has been running since before Christmas '23.

The battery voltage is still 3.30V, even after 6 months!

Quick estimate points that my original calculations for 10+ years life on a single battery charge are very viable.

Picture attached.

Cheers!
Case, face, battery and strap update
VALENTINE • 06/12/2024 at 14:48 • 0 comments

A lot has happened, and I haven't had the time to post an update.
The case, face, battery and strap, as well as some internals were completely redesigned.
Also working on screen illumination, and touch sensors, since the watch has no buttons.
Will post updates later, as I'm having way too much going on. Here are some quick previews.
Cheers!
Valentine
PCB Manufacturing with PCBWay
VALENTINE • 02/06/2024 at 22:51 • 2 comments

I got approached by PCBway who wanted to sponsor a batch of assembled prototypes.
It was a rather significant amount, so thank you again! PCBWay went out of their way to sponsor it, way to go!
PCBs have just arrived from PCBway, many thanks for supporting this project by sponsoring the PCB's. They have come out looking great, everything is very sharp and the finish is good. Their customer service was very helpful and responsive which was great.

The board worked as soon as I plugged it in. So far I haven't tested all sensors, that will come later.,
Other then that I don't really have much else to report, everything works and its been a great success, I couldn't have hoped for a better outcome so far. Now I'm just back to writing firmware which is going to take forever for me. If someone has many of hours of free time on their hands good, I don't. Thanks again to PCBway for supplying pcbs for this project, I do really appreciate it.

The PCBs are rather costly due to being fully SMD flex-PCB, which is a really challenging process.
Attached is a macro of the flex PCB.
One good thing about PCBWay is that they will source all components for you, you don't have to rely on pre-sourced in-stock components and separately buy them, as with other PCB manufacturing outfits. Also, my PCBs arrived sealed in antistatic bags, which was a nice touch.
One last thing, PCB Way will send you pictures of the assembled product before shipping, for you to visually check the assembly. This is very helpful if you know certain component orientation is tricky, such as photodiodes, diodes, or other small polar components. I've had cases in the past where some component were rotated incorrectly and seeing a picture before shipping helped.
Case Design Progress
VALENTINE • 02/06/2024 at 02:38 • 0 comments

Got some time to look into the case design. This is the latest. Looks more and more like a watch.
Gold face (real gold foil, yes), aircraft aluminum, sapphire crystal.
Case design
VALENTINE • 02/02/2024 at 16:44 • 0 comments

In parallel I continuer working on the case design.

This is one of the latest iterations.
Ultra-low round Sharp color LCD
VALENTINE • 01/30/2024 at 04:10 • 0 comments

Laid my hands on really large 1.4 inch round ultra-low power transflective color Sharp LCD, will work on it in parallel, as the controls are rather complex. This is a parallel effort and might not be progressing as fast as the rest. Got two in case one breaks. These are super-hard to find, I was very lucky to procure two pieces which were miraculously in stock from a European distributor. Those are used in very high end smartwatches.
New case with LCD screen
VALENTINE • 01/30/2024 at 04:05 • 0 comments

Designed a new watch case to fit the battery and larger screen. It's a very long story but here are the pictures. Good progress.
Touch screen sensors
VALENTINE • 01/30/2024 at 04:01 • 0 comments

Prototyping a touch sensor screen to get the buttons working since the watch has no physical buttons. I decided to get away with the photodiodes due to complexity and added thickness.
So far so good, lots of challenges mainly with physics as the sensors are behind a thick glass face, but seems to be working, with caveats.
Powerplant efficiency
VALENTINE • 01/22/2024 at 03:28 • 0 comments

It's a long and convoluted calculation but bottom line, the design as is today will cost me 2uAh, so that would be about 50 years on a 1Ah battery drained to the bottom. I don't like that. On a 100mAh that's 5 years. Upside is of course solar charging, so make some lose some, make more than lose I guess.
The calculation was that I lost 1V in 2.45 minutes on a 400uF battery, so F*V/3600 that's about 100nAh, with 0.05 hours, that's 2uAh, give or take. Sssssss......
Project Log
VALENTINE • 01/22/2024 at 01:16 • 0 comments

Haven't updated the log in a while, due to being really busy with the case and the powerplant.

I did a full redesign of the case, will post a new log entry when I get it machined. Designing a case and manufacturing it was a major effort, hopefully this time it will work, this is revision four. The R2 and R3 were really nice but sadly they could not be manufactured. Details later.

Powerplant: also some setbacks. The manufacturer could not properly SMD the design, I'm in a process of re-making it, it will take a week. Meanwhile, I was able to literally carve out (as in with a PCB mini-saw) the power portion of the design and test it.

Picture attached. I managed to read through the fifty pages of documentation for that IC and I'm getting it to the point where it's testable. There are moments I don't fully understand, but will clean up along the way.

Powerplant notes.

1. Connect EN to GND for gen mode. Connect to High for ship mode. Probably reed contact.

2. Connect vout-en to batt-ok. This will set the cold-start automatically vout-en to disable to charge the battery without powering the main circuit load, then exit cold start and enable the vout once the battery is charged to pre-set level and switch to battery + solar unless the battery drops and disable the circuit. I hope I'm doing it right.

3. For some reason the resistors I chose using the provided spreadsheet resulted in 1 volt under for both the charge and voltage out levels. This needs to be investigated, as the spreadsheet might be off or wrong or I got something incorrect during component and PCB design. It's easy to fix by experimentally tweaking the resistors however I don't feel comfortable tweaking without understanding why it works/doesn't work as designed and documented.

Pic under of the setup.

Another major milestone achieved!

Cheers!

View all 76 project logs

Discussions

Jackson wrote 06/20/2024 at 23:28

I'm working on my own smartwatch project, and it seems we've made a lot of similar design choices. I'm curious how you accomplished waterproofing? Is there a clear place that fits over the display that I can't see? How are you getting a good seal with (what appears to be) 3d printed parts?

Are you sure? yes | no

VALENTINE wrote 06/25/2024 at 16:03

No buttons, tight tolerances, epoxy seal. The 3D printed case is experimental, the final variant is CNC milled high precision, with sapphire lens. Please see my latest log updates.

Are you sure? yes | no

VALENTINE wrote 06/25/2024 at 19:39

CNC high precision mill and sapphire lens, no buttons.

Are you sure? yes | no

Keith wrote 02/01/2024 at 01:14

https://kairoswatches.com/ make expensive designer watches with a transparent OLED over a mechanical face.
Maybe you could fit a transparent colour OLED over a low-power e-ink display?

Are you sure? yes | no

VALENTINE wrote 02/01/2024 at 02:14

Interesting, thank you.

Are you sure? yes | no

Ezra wrote 01/03/2024 at 01:11

what if you added a small coil and magnet thingy so when you walk, it induces a charge into the coil to power the system/charge the battery.

Are you sure? yes | no

VALENTINE wrote 01/03/2024 at 16:01

Hi there. Electro-mechanical energy harvesters are not applicable in this use case. The complexity and cost associated with an electro-mechanical harvester, combined with the narrow specifications make it a niche/fringe solution ill-suited for a smartwatch.

Are you sure? yes | no

Ezra wrote 01/03/2024 at 16:48

that makes sense. It would still be cool though. Maybe a belt that has an inductive charging transmitter by the pocket and a receiver coil in the watch so it charges from something (idk) while you have your hand on your pocket?

Are you sure? yes | no

VALENTINE wrote 01/03/2024 at 20:54

How is this any different from light when you wear it? Light is pure electromagnetic radiation. Free source, too (sun). And I don't have to scratch my crotch each time I have to charge it, either.

Are you sure? yes | no

VALENTINE wrote 01/03/2024 at 20:58

In case you are interested, it's been done before, and there are very mature applications.

https://www.kinetron.eu/mechanical

https://sequentworld.com/en-us/pages/n-technology

https://www.ventura.ch/index.php/uhren/sparc-mgs/w-51-s.html?___store=euro_english&___from_store=euro_deutsch

Cheers!

Are you sure? yes | no

Ale o co chodzi wrote 12/30/2023 at 15:57

meybe You wrote to pine64 team and ask about create first revision of hardware? for example 20-100 items. for testing on more than one person

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VALENTINE wrote 12/30/2023 at 18:00

Never heard of pine64 team , what is it?

The watch is really complex, I'm not sure anyone will be willing to invest $20000 for 100 items. Do they have $20000?

Thank you for the suggestion.

Are you sure? yes | no

VALENTINE wrote 12/30/2023 at 18:18

I checked, if that's what it is, pine64.org ?

They already have a watch, so I'm not sure they want to add a competing product to what they have.

Cheers!

Are you sure? yes | no

aaaaaa wrote 01/06/2024 at 18:50

ask and You will be suprise

Are you sure? yes | no

Yaroslav wrote 12/06/2023 at 14:55

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 12/06/2023 at 15:20

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

Is possible create a tamagotchi version?

or old fasion clock pocket? for example with solar panel? https://hackaday.com/2022/03/30/solar-harvesting-is-better-with-big-capacitors/ or ..... peltier power https://hackaday.com/2018/07/05/a-flashlight-powered-by-your-hot-little-hands/

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 https://www.crowdsupply.com/yellow-beak-computer/ello-2m , 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

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.

Cheers!

Are you sure? yes | no

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

😉

Are you sure? yes | no

powiadam.ci wrote 11/30/2023 at 11:08

https://en.wikipedia.org/wiki/Pixel_Qi

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

https://en.wikipedia.org/wiki/One-time_password

Are you sure? yes | no

sup wrote 12/04/2023 at 09:28

we waiting ;)

power is very important in mobile project

Are you sure? yes | no

VALENTINE wrote 11/30/2023 at 15:19

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.

https://www.hannspree.eu/uploadfiles/202304/20230427163724-8qlvc230td.jpg

https://www.hannspree.eu/product/21.5PaperDisplayTransflective/

Are you sure? yes | no

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

thanks @powiadam.ci

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 https://flipperzero.one/ precisely because you can write your own script.

Are you sure? yes | no

VALENTINE wrote 11/30/2023 at 18:17

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.

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nephrita wrote 11/27/2023 at 14:38

Beautiful work!

Are you sure? yes | no

VALENTINE wrote 11/27/2023 at 14:56

Thank you!

Are you sure? yes | no

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

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

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.

Cheers!

Are you sure? yes | no

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

I found some screen shots and designs that could help understand. Pebble worked in color and monochrome. Here is the link http://alexanderkirov.com/works/pebble-os

Are you sure? yes | no

VALENTINE wrote 11/24/2023 at 01:22

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

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

LS013B7DH05

https://d7rh5s3nxmpy4.cloudfront.net/CMP7377/files/LS013B7DH05_15Jun15_Spec_LD-27503A.pdf

https://www.digikey.com/en/products/detail/sharp-microelectronics/LS013B7DH05/5799456

Are you sure? yes | no

Yaroslav wrote 11/22/2023 at 20:38

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

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

Are you sure? yes | no

fdufnews wrote 11/14/2023 at 08:45

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

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

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

Ken:

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.

Cheers,

Valentine

Are you sure? yes | no

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

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

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

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trialexhill wrote 11/14/2023 at 03:59

Ha!

Are you sure? yes | no

Smartwatch 10 Years Ultra-Long Battery Life

Description

Details

Project Logs

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Battery life update at 6 months : 10+ years !

Case, face, battery and strap update

PCB Manufacturing with PCBWay

Case Design Progress

Case design

Ultra-low round Sharp color LCD

New case with LCD screen

Touch screen sensors

Powerplant efficiency

Project Log

Discussions

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