Casio FW-91 replaced with smart internals
(crowdsupply.com)73 points by sponno 10 months ago
73 points by sponno 10 months ago
It's a temperature compensated quartz watch, accurate to around 10 seconds per year. This puts it right up there with the highest end quartz watches. Even if you don't care about any extra features, it's worth it just for this.
It's also the only watch I've ever seen with a fully customizable and calibratable pulsometer. I know because I added that feature myself after shopping for watches and not finding a single one that had it. Use it every day at work too.
I agree with your points.
Where are you getting a genuine F91-W for 5€? A replacement 71604002 band costs me €8!
They do, albeit without a heart rate monitor.
https://www.casio.com/us/watches/casio/product.ABL-100WE-1A/
With a heart rate monitor it's considerably more expensive.
I respect these developers spending months and months to do something really not necessary and just for fun. I doubt they would make millions selling this so it is purely for their entertainment. I hope to find a hobby project to dedicate myself like these people one day.
Well I absolutely needed this watch. It's a world class watch, it's hackable, it's cheap, it doesn't phone home, battery lasts over a year, LCD visible is always high.
It's actually the only watch with all the features I want. It's got a pulsometer built in and I added a calibration feature to let the user set the scale. As far as I know it's the only watch to ever allow this. Use it every day at work.
Bluetooth could have such a tiny power draw if they would just have lower update rates.
I don't see any reason things like watches and tracking tags in some couldn't have 10yr life on a coin cell, or like 30 years with an LTO you charge monthly.
Deep sleep currents can be in the nanoseconds, and we only need power for a few milliseconds every minute to transmit an "I'm here" beacon.
Step counts and heart rates are different, but even that can be optimized a lot if you don't need 100% perfect data
If you missed this detail, they've also designed a replacement LCD which adds a few carefully-chosen segments and symbols. The end result still looks very similar to a stock watch, but is much more flexible: https://www.crowdsupply.com/oddly-specific-objects/sensor-wa...
This is sensorwatch.com and it is nice. It has been around for a while.
I get the fun part of engineering this but can't put aside that it doesn't bring that much new feature, a thermometer, international time, more advanced chronometer. That's all thing that I don't really care about.
On the downside, you loose the cheap aspect of this watch and the battery life is divided by 7. From 7 years to supposedly a full year.
I buy a f91w because it cost less than 5€ and I don't care to break it or get it stolen.