8 ms·
Taking a $15 Casio F91W 5km underwater
- mrweasel 2y agoThe F-91W is such a fun little watch[1] and people have done the weirdest stuff with it. There's a guide to make the mod on Youtube[3]. There's also the TOTP in a F-91W[2] 1) https://www.youtube.com/watch?v=r6REKCs4-1M https://www.youtube.com/watch?v=r6REKCs4-1M 2) https://blog.singleton.io/posts/2022-10-17-otp-on-wrist/ https://blog.singleton.io/posts/2022-10-17-otp-on-wrist/ 3) https://www.youtube.com/watch?v=jLmAq0epfrI https://www.youtube.com/watch?v=jLmAq0epfrI
- fnordian_slip 2y agohttps://www.reddit.com/r/F91Ws_on_NATOs/comments/f9udxl/the_bestworst_casio_f91w_modifications_awards/ https://www.reddit.com/r/F91Ws_on_NATOs/comments/f9udxl/the_... also deserves a mention here, and /r/f91w for more general stuff.
- Cumpiler69 2y ago> https://www.youtube.com/watch?v=jLmAq0epfrI https://www.youtube.com/watch?v=jLmAq0epfrI FWIW, a correction is required here. Oil-modding a F91W will NOT make it a dive watch replacement as the video creator claims several times. A dive watch is designed to be operated at that depth while the weak o-rings around the pushers on the F91W will give up when you use the buttons. Oil modding on it holds up during a dive as long as you'll never push the buttons, so it's more of a neat party trick for show than anything to daily drive.
- eadmund 2y agoModified by oil-filling, though.
- klabb3 2y agoYeah but.. it’s just the way of gases and liquids under pressure. Even if you could sustain the pressure with gas it would be an unnecessary implosion risk if it’s pierced. As long as it still functions fully including on the surface, I wouldn’t qualify that as cheating. More like us biological weaklings who need ~1atm can be cheap and skip the liquid/resin because if we accidentally end up in space or the deep sea we generally have bigger problems than checking the time.
- Liquix 2y agoeasy solution: fill yourself with oil before diving. checkmate, nation-state navies
- neutered_knot 2y agoAs depicted in the move "The Abyss". https://en.wikipedia.org/wiki/Liquid_breathing https://en.wikipedia.org/wiki/Liquid_breathing
- euroderf 2y agoAlso the aliens in the Sylvia & Gerry Anderson TV series "UFO".
- deleted 2y ago[deleted]
- LeifCarrotson 2y agoI've read that it's possible to breathe oxygenated liquid perfluorocarbons, but something about the idea is just terrifying to me. I think it's the "fluoro" bit specifically that scares me, even moreso than the "liquid" part.
- nradov 2y agoHumans can't really "breathe" oxygenated liquid. Our diaphragms aren't strong enough to move sufficient liquid in and out of the lungs, so it can only work with external mechanical ventilation. This is occasionally used as a salvage therapy for patients hospitalized in critical care but is totally impractical and unsafe for any sort of diving. In the real world outside of sci-fi movies, any human diving much deeper than about 0.5km will have to be done in an an atmospheric diving suit.
- yencabulator 2y agoBased on a video of a mouse I saw, I'd describe perfluorocarbon breathing more as you can drown in it and not die.. it definitely did not look pleasant.
- Mogzol 2y agoI think it would have been interesting to send two down, one oil-filled and one not and see at what depths they break (or don't). The watches are cheap enough that destroying one isn't much of a loss.
- landgenoot 2y agohttps://www.youtube.com/watch?v=jLmAq0epfrI https://www.youtube.com/watch?v=jLmAq0epfrI It breaks
- EVa5I7bHFq9mnYK 2y agoSo the link to espionage is that a spy diver can dive to -5km wearing that watch and the watch will stay whole. ChatGPT can be really stupid sometimes.
- mrweasel 2y agoIt's actually two separate articles in one, but they had to merge them to make the content work for their oddly specific website.
- millitzer 2y agoThe second half of this article would make a great movie.
- jrgifford 2y agoI might be reading into it, but there seems to be a bit of a condescending tone with this comment. The "oddly specific" website has 191K followers on Instagram[1] and has done interviews with Hodinkee, one of the most well known 21st century watch magazine/blogs. It is not that different from others that hit the first page here on HN. [1] https://www.instagram.com/watchesofespionage/ https://www.instagram.com/watchesofespionage/
- mrweasel 2y agoYou reading a bit to much into it. I did check out their content before commenting, there's also three previous links shared on HN. I was just amazed that they are able to have enough content for something that seems extremely specific.
- cbsks 2y agoFor watch hackers, there is an alternate PCB with programmable microcontroller available for the F91W https://www.sensorwatch.net/ https://www.sensorwatch.net/ I got one for Christmas and it has been super fun to hack on. I programmed a new face for mine that displays the current tide level, and next high and low tides.
- noja 2y agoWhere did you get the data for the tides?
- cbsks 2y agoThere’s an algorithm you can use to calculate future tides but it’s complex and I wasn’t sure it would even run fast enough on the watch. I gave up after a few hours and ended up generating an array of high/low tide levels and times for the next few years. NOAA has all the tide data you could possibly want, and an api to grab it. https://tidesandcurrents.noaa.gov/tide_predictions.html https://tidesandcurrents.noaa.gov/tide_predictions.html https://api.tidesandcurrents.noaa.gov/api/prod/ https://api.tidesandcurrents.noaa.gov/api/prod/
- somewhatoff 2y agoCasio do have a tide watch, which presumably uses that algorithm: https://www.greatwatches.co.uk/collections/men/products/casio-w-753-2av-blue-moon-and-tide-graph-dual-time-4-alarms-watch https://www.greatwatches.co.uk/collections/men/products/casi...
- zardo 2y agoAnd this approach actually works for inland waters since NOAA predictions are accounting for geographic effects. (e.g. the tide in Seattle is drastically different in timing and magnitude from the Pacific Coast)
- cbsks 2y agoNOAA publishes the harmonic coefficients for each tide station, so if you hard code those constants into your program you should be able to generate accurate tide predictions. I looked into it a bunch before it started to feel less fun and more like “real work”. https://tidesandcurrents.noaa.gov/about_harmonic_constituents.html https://tidesandcurrents.noaa.gov/about_harmonic_constituent...
- istultus 2y ago[flagged]
- ndiddy 2y agoWas disappointed that he only brought a modified oil filled watch to 5km underwater. Would have been interesting if he’d have strapped a stock watch next to it so we could see when it would break.
- rhd 2y agoThis video might be of interest to you- https://www.youtube.com/watch?v=iOT8XU1ss3E https://www.youtube.com/watch?v=iOT8XU1ss3E (Do Oil-Filled (Hydro Mod) Watches Actually Dive Deeper?)
- homebrewer 2y agoA very similar model (A158 — they differ only in the bracelet) breaks at 200 m: https://youtu.be/G3iMkeF8qmA https://youtu.be/G3iMkeF8qmA https://youtu.be/sep5Tw-55yw https://youtu.be/sep5Tw-55yw The timekeeping mechanism keeps working fine, though, it's only the display that's busted.
- dnisbet 2y agoYep would have loved more on when the watch (unmodified) would actually break and also how you would fill it with oil? There can't be much space inside, at what point does the viscosity of the oil matter? how do you know you've got all the air out?
- aidenn0 2y agoI'm assuming they are using mineral oil; I've not filled a watch with mineral oil, but I have worked with it. Mineral oil is not particularly viscous; some gentle tapping is probably enough to get all the bubbles out. Here's a video of a PC immersed in mineral oil with an aquarium bubbler and you can see the bubbles rise fairly quickly: https://www.youtube.com/watch?v=tUBvWXH1hLs&t=110s https://www.youtube.com/watch?v=tUBvWXH1hLs&t=110s
- OliveMate 2y agoI've been stuck down the Casio modding rabbit hole as of late. I knew filling the watch with oil ('hydro-mod') lead to a crisper display with better viewing angles and increased water resistance, but to see a watch with minor splash resistance operate as such depths is insane. Worth mentioning some drawbacks before you get your precision screwdrivers out. Doing it will make your watch get stupidly hot in the sun, the process can be messy, and sometimes certain mechanisms/features can break as a result of it. Best to check what others have done before you.
- cenamus 2y agoWhy does it heat up in the sun?
- two_handfuls 2y agoMy guess: higher thermal mass, so over time it can accumulate more heat than a non-filled watch.
- iancmceachern 2y agoI expect it has more to do with thermal conductivity
- Cerium 2y agoThe back will get hot since the oil improves the heat transfer from the front to the back. The sun will always heat the front, but as long as the heat transfer rate to the back is low enough it won't feel hot - your body will absorb the heat and reach an equilibrium temperature which feels natural.
- kali_00 2y agoNotably, there was no attempt to operate the watch at such depths. Pressing a side button would be an interesting test, for instance. Many "water resistant" watches, rated to a certain depth are only rated so, given the not inconsiderable caveat of not being able to operated - just looked at. The higher end, more expensive models claiming full waterproof ability don't typically have such functional restriction.
- protimewaster 2y agoIt seems like actually pressing a watch button at that depth would be quite a feat of precision engineering itself. Are ROV arms typically that precise that it would be possible to see well enough and finely enough control the arm to press the button?
- curiousObject 2y agoNot sure if the buttons function, but the watch is displaying time in the photos, for 50 minutes of the descent at least.
- titanosaurxxl 2y ago[flagged]
- aurizon 2y agoThese watches often have a quartz crystal - the little can would crush and the oil would damp oscillations, so they might have a laser trimmed RC loop - which would be cheaper as well as crush-proof?
- deleted 2y ago[deleted]
- maxglute 2y agoI just a fitness band in a f91w or w59 body.
- walrus01 2y ago[flagged]
- deleted 2y ago[deleted]
- t1234s 2y agoAny hacks to fix the useless light?
- echelon_musk 2y agoBuy a W-86-1VQES instead.
- jibe 2y agoThere is one, but requires another Casio watch to borrow the backlight from. https://youtu.be/9-jd_7eXACU https://youtu.be/9-jd_7eXACU
- rsaz 2y agon-o-d-e has what he calls a data runner mod which includes simply swapping the stock green light with a brighter white one. I’ve had one for years now, and its still not ideal, but definitely better than the original: https://n-o-d-e.net/datarunner.html https://n-o-d-e.net/datarunner.html
- racnid 2y agoThere are some diffuser mods available too that look like they would make a big difference.
- ozuly 2y agoYou can buy replacement backlight spreaders off of etsy. I did it to mine and the backlight is now usable..
- _tariky 2y agoI own legendary GW-5000U. It is amazing to see those cheaper alternatives are as good as 5000U. I'm wondering is there any other brend except Casio that has watches as amazing as those are.
- franczesko 2y agoI think Garmin is doing pretty interesting outdoors models, however I prefer Casio due to simplicity and... nostalgia
- ErigmolCt 2y agoI’ve been using a Garmin for swimming, and it’s hard to beat the functionality, it’s been a game-changer for me
- discreteevent 2y agoFYI Casio recently brought out a minimalist series of the F-91W (same watch - just a bit less chrome on the face) e.g. https://www.casio.com/europe/watches/casio/product.F-91WB-1A/ https://www.casio.com/europe/watches/casio/product.F-91WB-1A...
- Mistletoe 2y agoIf there is one thing the original is, it’s too flashy. :) Kidding aside, that looks pretty neat.
- bookofjoe 2y agoOoh, these are beautiful: Blue: https://www.creationwatches.com/products/casio-digital-350/casio-pop-digital-blue-bio-based-resin-strap-quartz-f-91wb-2a1-unisex-watch-27705.html?currency=USD&srsltid=AfmBOopjnuEWxeffCkIiOoiTF5aKh99sz6L2_Na_fxlXn2gf6hqZqzUBY74&gQT=2 https://www.creationwatches.com/products/casio-digital-350/c... Grey: https://www.creationwatches.com/products/casio-digital-350/casio-pop-digital-gray-bio-based-resin-strap-quartz-f-91wb-8a-unisex-watch-27706.html?srsltid=AfmBOooZPho89bYQov9JIIhiy2hqWRUt7F6HH9qoYSPAC8EAVF-SfqkM https://www.creationwatches.com/products/casio-digital-350/c... Black: https://www.amazon.com/Casio-Environmentally-Friendly-Bio-Based-Indicator/dp/B0DDWDKRWT/ref=asc_df_B0DDWDKRWT?mcid=38ddcb87cfc737ebbca34e62eee8fcf7&hvocijid=14863530072395194302-B0DDWDKRWT-&hvexpln=73&tag=hyprod-20&linkCode=df0&hvadid=721245378154&hvpos=&hvnetw=g&hvrand=14863530072395194302&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9008335&hvtargid=pla-2281435178538&th=1 https://www.amazon.com/Casio-Environmentally-Friendly-Bio-Ba... White: https://www.amazon.com/Casio-Environmentally-Friendly-Bio-Based-Indicator/dp/B0DK42VCQ4/ref=asc_df_B0DK42VCQ4?mcid=27cc2c01209234988b4108680c334459&hvocijid=12783622169592000285-B0DK42VCQ4-&hvexpln=73&tag=hyprod-20&linkCode=df0&hvadid=721245378154&hvpos=&hvnetw=g&hvrand=12783622169592000285&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9008335&hvtargid=pla-2281435178618&psc=1 https://www.amazon.com/Casio-Environmentally-Friendly-Bio-Ba...
- devindotcom 2y agoWow, love this. I of course love the classic color lettering (which really is quite tasteful) but I'm going to cop a "minimalist" black style for more formal occasions!
- jessekv 2y agoI found one of these while free diving. Wiped it off and wore it for several years, until I lost it while free diving.
- wwilim 2y agoSo did I!
- ASalazarMX 2y agoWhy are these so easy to lose?
- verelo 2y ago*share
- prova_modena 2y agoThe straps tend to break after a few years. Casio G Shock straps last a lot longer, despite being very similar. Not sure if it is because the F91W strap is thinner or made of a less durable material.
- wwarren 2y agoThe circle is complete
- ErigmolCt 2y agoAnd are you thinking about getting another one, or just letting fate decide again?
- iamthemonster 2y agoThen something happened which the Casio F91W did not intend. It was found by the most unlikely creature imaginable.
- deleted 2y ago[deleted]
- ge96 2y agoAwe the Seal kiss, 20,000 Leagues vibe
- __mharrison__ 2y agoI modded mine with olive oil when I bought it. Pretty indestructible.
- dr_kiszonka 2y agoIs that a real CIA challenge coin? It has what look like strange imperfections.
- runjake 2y agoLooks like it. The imperfections are just glare from the lighting.
- jigneshdarji91 2y ago> Incredibly, the F91W survives its journey to an official 4,950 meters—an astonishing 16,240 feet—and back. Findings. > 4,950 meters under the surface, the pressure is approximately 7,227 pounds per square inch, which is well over three tons pressing on the watch. For context, that’s a Dodge Ram 1500 or a young adult hippopotamus parked on every inch of your F91W. As Americans, we’ll do anything to avoid the metric system, but using scientific terminology, we’re talking about a shitload of pressure. Appreciate the joke.
- franczesko 2y agoThe new abl-100, besides more wearable size could have a nice tinkering potential
- johng 2y agoIt's amazing how often this comes up on HN... I'll have to get one. https://hn.algolia.com/?q=f91w https://hn.algolia.com/?q=f91w
- nejsjsjsbsb 2y agoThis or Pebble? What is HNs heartfelt favourite?
- ErigmolCt 2y agoThe fact that a $15 watch, plus a little mineral oil, can handle 5,000 m underwater is just peak "good enough" engineering!
- fhfjfnnf 2y agoIs there any reason a watch without moving parts filled without any gas pockets _would_ stop working? Don't get me wrong, it's a nice demonstration but kinda expected outcome
- mulholio 2y agoI had a beloved F91W that I used for years. One day, when surfing in Morocco, it gave out and the screen became foggy before showing me an error code and never recovering. I guess I should have gone deeper.
- fennecfoxy 2y agoThis model doesn't seem to display error codes for anything. I think their failure mode is just to "not work properly anymore".