Casio F91 smart watch reboot | Hacker News Reader

Casio F91 smart watch reboot

gitlab.com

490 pointsrcarmo94 comments

Wow. There is another project doing a similar thing, but they don't have bluetooth nor an OLED display (they reuse the same display) so it's not nearly as useful in daily life, though still very impressive work nonetheless.

But this is really amazing work. I hope you find some collaborators to continue!!

I recently got an F-105W which I had when I was a teen (which is basically the F-91 but with a cool glowy EL backlight). And one thing that really surprised me how small that thing is. It seemed bigger at the time.

I'm really amazed how much technology this project managed to fit in that tiny case. Battery, OLED, bluetooth.. Just wow.

I would pay for this, I was thinking of buying that other project on crowdsupply but without BT connectivity I just don't really have any use for it.

I assume you're referring to the Pluto watch? https://github.com/carrotIndustries/pluto-fw

I suspect they're referring to the more recent Sensor Watch: https://www.crowdsupply.com/oddly-specific-objects/sensor-wa...

Quick review: I have one of the early units and I've really enjoyed using it. It's totally hackable, well documented, and I fully anticipate using mine for the next decade or longer. It's far from a smartwatch - it's more like you're sitting in on the Casio product meeting where they wrote the original F-91W specs. The year-scale battery life remains, but it comes with the ability to fully customize the watch behavior. For me, that meant adding sunrise/sunset and moon phase faces. I might build a quick-timezone switcher in the future.

It is indeed very nice, I would just really want some kind of wireless connectivity for any of the usecases I could come up with :) Otherwise I'd have bought one for sure.

No, the other one on crowdsupply that the other person below was talking about. I didn't link to it as it was already mentioned in other places in this thread as well.

There's an active F-91W watch hacking project (with somewhat different goals) here:

https://www.crowdsupply.com/oddly-specific-objects/sensor-wa...

oh hey, this is my project! Sensor Watch definitely has different goals — less smart, more watch — but I love this, and I love how the F-91W represents such a blank canvas for folks to project their vision onto. It's small and so very thin (at home on any person's wrist), water-resistant and vaguely indestructible. It's also so inexpensive and ubiquitous that you can take it apart and hack on it without feeling like you're breaking something important, and you can safely assume that anyone in the world can probably grab one at a local store and hack along at home. It's a wonderful object.

Wow this looks great, I will be following the project.

It's a pity that shipping and taxes outside the US effectively doubles the price.

This is the barebones Android smart watch I want. As a side note why won't apple make it's watch work well with android - wouldn't that add a few million users? ~ or do they sell it as a loss leader for IOS?

I want a future where we have bare-metal versions of smart watches with low power screens, thin form factor and long battery life compete with full feature dick tracy phone watches.

> As a side note why won't apple make it's watch work well with android

This is the way Apple works. You don't own enough products so you aren't worthy of full functionality. Last time I checked you can't update Airpods firmware without another Apple device nor can you change settings on the pro XDR display without a device running macOS.

This is the way a lot of companies work and have historically worked. Why spend a ton of resources supporting every operating system and hardware combination out there for all of your devices when you have a perfectly good way of doing it in house?

> Why spend a ton of resources supporting every operating system and hardware combination...

Making it so Android users can update their bluetooth headphones is not supporting every hardware combination. Adding a OSD to your monitor so people don't need OS X specific software to change their monitor settings is not supporting every operating system or hardware combination.

They aren't just bluetooth headphones, they are airpods, you bought airpods because you are in the iecosystem.

Who buys airpods and expects them to work well with anything other than an apple device? You buy them because it'll work well in their ecosystem, really well.

I have some cheap earbuds that work decent everywhere, as well as a generic bluetooth speaker, but I generally use my apple earbuds because they work the best with what I have.

When you support only your ecosystem you can improve the connectivity that bluetooth alone doesn't allow.

> Who buys airpods and expects them to work well with anything other than an apple device? You buy them because it'll work well in their ecosystem, really well.

This feels like a hindsight kind of statement. We are conditioned to think that since it's Apple it won't work well with other ecosystems, so "you don't buy apple if you don't have everything apple" which... I mean, it makes sense but it's the reverse logic. I bought my pixelbuds and I can use them on a wide range of bluetooth devices that aren't Google-specific, and they work as you'd expect them to. It's fine if Apple wants to have Apple-specific features if you use them with Apple devices, just like Google pixelbuds have specific integration with google home app and similar google-specific devices, but at least the core bluetooth functionality (+ settings) should be provided to be able to work on any device.

Disclaimer: I've never used airpods so I have no idea how they work, just commenting on the logic of the original statement alone.

> I have no idea how they work

There is definitely some proprietary “glue” in there. One nice thing about them is that you pair them to one device and then all of your other iCloud devices can see them. I would not expect that kind of feature to work elsewhere for obvious reasons. I could be wrong?

They also support spatial audio which is now supported with Android.

There are definitely features of the AirPods which are new or were new when they were released. It’s up to Apple to support those features on their own hardware/OS. It’s up to others to add support to their own operating systems if they deem it worthwhile. Similar goes for other hardware. Yes, the hardware works differently than so many generic components out in the world but that’s kind of the point.

I have airpods and an android phone. They work well now (I really am not interested in spatial audio). They did however work pretty badly until I connected them to an iphone to allow the firmware to update. I dislike the ecosystem argument. They are just Bluetooth earphones... Quite expensive ones at that.

The current iteration of the Samsung Buds Pro didn't have an iOS app, which was annoying.

Ended up just getting a UTWS5 and Moondrop Katos and being a lot happier.

What I'm hearing from you is that we need to regulate companies to mandate interoperability.

Could you imagine a world where telephones couldn't make calls to each other or cars needed special gasoline that was only available from gas station chains that licensed it from your car maker?

What a terrible world that would be.

Why do we accept similar things with computers?

Although, Tesla continues to equip a proprietary charging port and an adapter is required to use CCS1. Futuristic companies seem to hate standards.

Luckly EU put a boot to the neck of that dumbass idea and EU Teslas have CCS2 port.

I wonder if mandatory opening of interoperability protocols for popular products would improve health of electronics markets.

> Futuristic companies seem to hate standards.

A standard is just something that gets adopted by a bunch of people. There are competing standards for all kinds of things… the market generally decides what standards win. Any company doing something new is by definition attempting to set a new standard.

There was a time when standards would be developed voluntarily by the major players for the parts that are tangential to their innovation. Apple's success with the iPhone isn't because they use a connector that is prone to shorting and susceptible to lint. Tesla's success in electric cars isn't because they didn't help develop a standard connector. However maybe they plan to pivot to overpriced electricity at their proprietary stations if they lose their competitive advantages, who knows?

When innovation was occurring in integrated circuits the companies standardized on the 0.1" DIP. Then as needs for smaller packages came they worked together on TSSOP and others. Obviously the innovation isn't a matter of packaging.

The original iPhone/iPod 30-pin dock connector was just that: a dock connector. At the time, I recall a lot of different dock connectors and they were all proprietary and special built for the electronics they supported; That was the state of the art in the late 2000s. The next iteration was the lightning connector which is standardizing on USB. It was also better than any usb connector at the time because it could be inserted in either orientation that made physical sense. After a decade of use, we have a lot of expectations around connectors that we didn't in 2012... like pocket lint and well-worn/damaged ports.

If you look at the USB implementors forum, you'll notice many of the big players are there (including Apple.)

I would argue that the 0.1" DIP was a technology innovation of its own. It was adopted because it solved a problem with scalability of TO-5 and similar packaging which was somewhat round in nature, maybe borrowing from the design constraints of vacuum tubes? (complete guess on that part!) There are variants of DIP which have different dimensions than the 0.1" DIP we see almost everywhere today. While there may have been cooperation in choosing 0.1" DIP, I think it's more likely that available parts were largely made in this form factor and thus it was adopted.

I'm just saying that RCA didn't produce 0.1" DIP while Fairchild produced 2mm DIP, and then make people decide which overall format they're going to work with before buying breadboards and the like.

I mean considering the continuous erosion of consumers' rights on their devices and manufacturing trying the assume the position of licensor instead of seller, I don't have a lot of trouble imagining such a world. If Apple said that they will void the warranty on iCars if users put anything other than iGas and make the iGas connectors proprietary, I'm sure a lot of people would nod and queue up to pay, like they do now because the build quality of iCars is the best and they want their cars to just work.

I like the feature, it prevents my kids from putting the wrong fuel in.

I rest my case :)

> What I'm hearing from you is that we need to regulate companies to mandate interoperability. Could you imagine a world where telephones couldn't make calls to each other or cars needed special gasoline that was only available from gas station chains that licensed it from your car maker?

That's nonsensical - none of your examples came about from regulation, they were market-driven.

Yes, let’s choose something that will work with everything, say:

RS232 for any wired data connectivity 110 VAC for any kind of power 802.11b for any kind of wireless data connectivity …

Now that we have these mandated, let’s zoom to the present day and figure out just how bad of an idea each of those decisions were.

I don’t know what “mandating interoperability” would mean for all cases in the original argument. eg: Does someone need to write software that can run on every single operating system that supports Bluetooth to perform a firmware update for AirPods before releasing them? That sounds pretty abysmal for anyone that doesn’t have the resources to understand/target/maintain a process for BeOS/Haiku/Linux/Android/iOS/Windows/whatever my car’s console is running/etc.

OTOH, you could write a standard for firmware updates to devices over different channels and see who would adopt it. Make sure it is future proof and covers all currently known use-cases. If it’s adopted by enough people, you aren’t using your local government to write something in stone which will likely be outdated in a decade or so anyway.

110 V ? No one uses that!

I know this comment is somewhat in jest but you can buy sockets which are usb/usbc straight out of the wall. While safe and UL-listed, you might technically break local code by installing them because you would replace standard outlets with something (potentially) more useful to you. The code you might break is having a certain number of outlets per linear foot of wall.

Most modern electronics convert from 110VAC to something else and spend a lot of hardware dealing with the fact that they are given single-phase AC and actually need somewhat clean DC. The big exceptions to this would be things like heaters/ovens/stoves or incandescent bulbs which just use 110VAC (or 220VAC split-phase) directly. None of those exceptions require AC and some might even work unmodified with DC. The big issue with single-phase or split-phase AC that's annoying for DC devices is the fact that you can get no power 100-120 times per second when the voltage crosses 0. Thus we end up with giant adaptors/fancy power supplies that plug into the wall sockets and produce DC.

On a power-distribution level, we use AC because we figured out how to transform voltages easily early on. However, we couldn't always agree on frequency (or voltage, or connectors) and thus we have situations like Japan's power grid to this day. Fast forward and we now have efficient ways to convert DC voltage but still pay the cost of AC everywhere because it's both ingrained and regulated.

edit: 0-voltage crossing is 2x the frequency in AC

> nor can you change settings on the pro XDR display without a device running macOS.

You can't even natively change brightness nor volume on non-Apple displays, even though DDC/CI is a thing and third party apps can do just that. The Mac Mini M1 HDMI port is even crippled at the hardware level and DDC/CI flat out doesn't work there (works fine via USB-C which uses DP).

The usual public rationale from Apple is that a perfect experience can only be achieved within a fully owned ecosystem.

I don't quite buy that the core strategic intent is intentionally using this to push people into owning only/buying more of Apple stuff, I bet it's more about not having to handle dev, fixes, workarounds, and a storm of support cases for third party hardware that may be of less than stellar quality, and then Apple being blamed for things not working.

IOW brand image control + dev resources, not a sales ploy.

You might want to give the Amazfit Bip a go, it's as barebones as it gets. The only gripes I have with it is the craptastic app and the lack of vibration, it only has a beeper.

There's an open-source replacement app called gadgetbridge. (I'm not sure it works with the exact model you mention, but I did use it with a cheap Android watch from, iirc, Amazfit.)

Yeah, for me, what I really want in a smartwatch are the following:

1. long battery life. (as in a week+) 2. Always on display. 3. Notifications. (Ability to display all notifications that make a sound/vibrate in android, ideally also providing access to notification's quick actions, and ability to dismiss notification from phone. It should also provide incoming call notification, with caller name or number and hang-up button support). 4. Media controls for phone. (I don't really care about this, but if a watch lacks it, it would be suspicious). 5. Basic watch functions, like time, date, stopwatch, timer, alarms. (Possibly synchronized with android device, but not is not a requirement).

Beyond those five, things health sensors, app support or whatever are just bonuses.

The display should probably be a reflective display with optional backlight triggered by tilt-to-view, or even a button. It probably should use something like epaper or memory lcd to be low power. Honestly color is not even critical, although would be a nice-to-have.

Pebble came somewhat close, although its notification support was somewhat more limited than I would have liked. But I've seen nothing else since then. Everybody is too focused on apps, fitness sensors, etc, and have laughable battery life, even without an always on display.

You literally just described the Garmin Fenix (or a vast majority of their more affordable options, the Fenix is just the Jack-of-all-trades model).

  1) Gets about 14 days with default sensors (HR, GPS, altimeter, barometer, compass, etc) enabled (turning on high resolution Sp02, for instance, will knock it down to 6-8 days)    
  2) Yup    
  3) Yup, all features requested    
  4) Technically, only for a few apps. And it supports Android's media APIs better than Apple's. But they're there. This is probably the weakest supported of your requirements.    
  5) Admirably.

Maybe check out Pinetime, Bangle js 2 or Watchy.

https://www.pine64.org/pinetime/

https://banglejs.com/

https://www.crowdsupply.com/sqfmi/watchy

I love my F91 (I’m wearing it right now!), and I love minimalist smartwatches. So this is right up my alley. I hope it keeps moving forward!

> At this point (read more like a year ago) I am burnt out from this project and now I figured to open it up and hopefully more people can be involved.

This is not moving forward, it looks like the author is just lofting it up as a resource for others to use as a starting point for similar projects.

It might be up to you, dear reader, to take it forward yourself.

Deeply heartfelt thanks to the original author for taking it this far.

Very interesting. One thing I've pondered - this project contains various pieces of off the shelf hardware, and some custom 3D CAD files. These don't seem to fit as neatly into the way Git functions. Is there/has there been any attempts to replicate Git with Bill of Materials or 3D CAD data?

There are many softwares attempting to solve this problem. Airplanes, bridges, cars, robots, they are catalogued in these systems. They tend to fall under the "Product Lifecycle Management" or 'PLM' name of softwares. Or also "Product Data Management"/'PDM'. Tends to be enterprisey.

I've used those systems previously. Sadly, none seems to be functional on a distributed scale like Git functions for codebases.

You can specify custom diff algorithms to git, so you could say all .dwg files get diffed with something which knows how to parse the binary data and present a reasonable diff between the two versions?

I guess if that data can be easily represented as plain text then git would work ok?

I'm almost of the opinion that it should be thrown back on the software to convert their save files to text where possible. Binary files just aren't great for a wide range of issues further than just git.

The data for CAD exchange files is usually plain text, the problem is that the exporter doesn't try to preserve the same order of stuff as previous times that it was saved.

That seems almost asinine. It should be trivial to have a standard sorting algorithm so any implementation produces the same result.

Perforce and Plastic SCM are heavily used in certain industries. I think they're both superior to Git.

Plastic seems heavily tied to unity, so thats a hard pass for those of us who dont want to be slave to an engine.

It was purchased by Unity, but I don't see anything that heavily ties it to Unity. I've used it locally, and it certainly didn't require any Unity dependencies.

I first saw this from the Hackaday article (The Casio Smartwatch You Never Had) - https://hackaday.com/2022/07/20/the-casio-smartwatch-you-nev...

Hackaday is something I'd definitely recommend to the average HN reader if they like the hardware side of things.

I'd also recommend N-O-D-E's channel for anyone interested in such things, here's his video on his F91 mod: https://youtu.be/cvtvm7N_qj4

Recommend the title be changed to "Casio F91 smart watch reboot". It's kind of nonsensical as-is.

I would pay as much for this as I would for an Apple Watch.

Very cool. I'd prefer Sharp's memory display which uses power like ePaper display, but looks and works exactly like a traditional LCD with high refresh rates. And bluetooth/etc is not a feature, but a bug IMO; goes against the philosophy of F91.

Bluetooth is a good mechanism for configuration, even if it is wholly turned off during normal operation.

Forcing all setup to go through the needle's eye of a couple of buttons is profoundly limiting, and a wired connection would violate F91 design esthetic more.

A transparent back for the watch, and optical components, could open biomedical opportunities. There, Bluetooth readout of logged data would be useful.

The nice thing is that it is open source, I could just disable radios all together and save batt: https://gitlab.com/_Pegor/kepler_fw/-/blob/master/Firmware/f...

Or turn the radio on only in response to a button-press pattern, and automatically turn it off with a timer.

Could also do LED communication in that case.

This is what I've been waiting for.

I love Casio watches, I own many. I have dreamed about having an F91 with smart functionality, ideally, a private, security focused device.

I feel you might have hit the nail on the head.

Can't wait to see this grow.

from the repo readme it looks like the owner is burnt out from the project and that there's much to do. I wouldn't get your hopes up unless you're interested in helping out!

Yes, I understand that. However, now that more people know about it, and many see the potential, I would be surprised if some people don't run with it.

I would help out if I knew where to start! I'll have a read and see if I can dip in.

wow, amazing how much functionality they packed into this tiny case. this would be the only smartwatch on the planet that isn't comically chunky, while still giving you the two things you need (namely time and notification icons, so you can break the habit of checking your phone). I'd pay for this, no doubt, if only I could!

A huge amount of the bulk in smart watches is the health sensors and vibration motor. Can easily slim things down if those aren't required along with a big display.

that makes sense, and now that I've seen proof that it's possible to build a watch-sized smartwatch, I'm even more puzzled that not a single one is on the market

There’s also competition aspect. Full iOS/Android is required to be relevant in the market, so all mainstream smartwatches integrates equivalents to literally late 80s supercomputer in them. There are exceptions like Xiaomi watches, but they’re low-end, low margin options.

I think it’s plausible that none of operational nuclear warheads were designed with supercomputer clusters more than half as fast as the latest Apple Watch. Resources packed into watches are that plenty.

Have you checked out the Pebble Time Round? Pebble was purchased by Fitbit, who were in turn bought out by Google, but there is good community support (1). Recently, the original Pebble app was taken down by whoever last maintained it (Pebble? Fitbit?), so at the moment there's no iOS app. I'm using a Nokia Steel HR as a temporary measure, but it is nearly comically chunky. I can't wait to switch back - I miss the Pebble.

Bad Casio and Pebble comparison photos: https://imgur.com/a/LrS8xI4

(1) https://pebble-help-legacy.rebble.io/help.getpebble.com/cust...

If you're getting the stock band, you might want to buy some spares because they're the first thing to go.

Or replace the band with a NATO strap. I've been very happy with my conversion.

Check out r/F91Ws_on_NATOs for inspiration.

That looks beautiful!

The best thing about Casio watches was the battery life. It could last 7 years. While I can understand that this is a smart watch, the battery only lasts 15 days. So, there is still a very good reason to use those old watches.

Wow. Another project is doing something similar, but it doesn't have Bluetooth or an OLED display (it uses the same display), so it's not as useful in everyday life, but it's still very impressive work.

Awesome! Although I am personally a fan of the japan only F84 myself

W-202 here. Can’t live without the countdown timer :)

Does anyone else get annoying jittery scroll experience on mobile?

https://imgur.com/Dn6vQiY

Nope, works fine here on current webview and firefox nightly.

Has anyone looked into amazefit retro

Amazfit Neo is much bigger than F91

Amazing project! Great tribute to one of the greatest timepieces ever made.

I wonder if an eink display would work okay. Then it would last a month!

Or one of those new screens (MIP I think?) that may end up being what eink always wanted to be but with better refresh

MIP as in memory-in-pixel? Like the Sharp memory displays/LCD used on the Panic Playdate, for example? https://www.adafruit.com/product/4694

Yes, in fact Casio uses MIP displays in some of its recent watches, e.g. this Bluetooth connected watch has a 2 year battery life: https://www.casio.com/intl/watches/gshock/product.GBD-200-1/

Yea exactly. I was about to buy a new Pro Trek but given that I like negative displays I was considering waiting in case they switch to MIP.....although I was looking at the mainly analog models where the little screen matters less.

The GBDH1000 is worth looking into as well, packing not only the MIP display but a suite of sensors as well as being powered by a solar element.

The F91W is a classic, and I really love that this project exists.

This feels like a product that Casio should be selling.

so cool. would love to see this fit into a slightly larger footprint such as my square gshock tough solar (5610)

The Casio F91, as approved by Osama Bin Laden himself:

https://www.google.com/search?q=bin+laden+casio+F91&client=f...

Favored trigger mechanism for IEDs?

Well I sure wouldn't recommend it as an IUD

Hmm, might work better than many items actually used.

you may end up in Guantanamo https://www.theguardian.com./world/2011/apr/25/guantanamo-fi...

The watch with a "Usage in terrorism" section on Wikipedia: https://en.wikipedia.org/wiki/Casio_F-91W#Usage_in_terrorism

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