I wish there were a way to put the chip & antenna inside (or behind?) the watch casing.
While this is really impressive, putting something in front of the faceplate breaks the great F-91W look and feel for me.
Hacking a Casio F-91W digital watch (2023)
31–40 of 58 posts
Re: Hacking a Casio F-91W digital watch (2023)
#32The problem with this approach is, every once in a while - I think the bank sets the limit - the card will not accept any NFC transactions at all until a physical confirm-with-pin transaction is made. That frankenstein'd chip... no way it can ever be assembled back into a "holder" card without risking everything breaking.
Yes, at least according to the information I have, the card issuer sets the limit. It's not clear to me if the chip actually has to be physically slotted in for reading it, though. Can the confirm-with-pin step be done without contact, using NFC feature?
Again I guess it depends on the bank. I have to go through the full insert physically so that the contactless-count gets reset. And of course, it always happens when buying a pack of smokes or a drink at a vending machine that does not have a PIN pad -.-
Re: Hacking a Casio F-91W digital watch (2023)
#33I enjoyed reading this, a lot. Really not really sure why everyone’s more bothered by the use of ai to help write it. But you can’t please everyone.
Re: Hacking a Casio F-91W digital watch (2023)
#34F-91W backlight fix: https://www.etsy.com/listing/1448973768/back-light-spreader-...
Re: Hacking a Casio F-91W digital watch (2023)
#35I don’t know why Casio doesn’t just do something like this themselves, I’d buy it. Don’t need a super smart watch but do like contactless payment with a wrist.
Re: Hacking a Casio F-91W digital watch (2023)
#36hacking f-91w been very popular https://en.wikipedia.org/wiki/Casio_F-91W#Usage_in_terrorism
That's because the F91W was like Game Boy of watches. Or the Tetris under a 'Brick Game' branded cheap console. Every dad owned one. Reliable, cheap and damn long lasting.
The world's most sold digital watch. Widely available since 1989. There are even multiple clones out there for a fraction of the price.
Re: Hacking a Casio F-91W digital watch (2023)
#37I wish there were a way to put the chip & antenna inside (or behind?) the watch casing. While this is really impressive, putting something in front of the faceplate breaks the great F-91W look and feel for me.
Projects like ollee Watch seem to be able to stash it behind the front crystal or underneath the LCD.
Re: Hacking a Casio F-91W digital watch (2023)
#38> I thought it would be nice not to have to take out my credit/debit card from the wallet or my mobile phone from the pocket to pay, but instead, to bring the watch closer to the PoS and just pay with a pinch of modern-day magic .
I don't know, every time I see someone paying with their watch it looks super awkward when they have to twist their arm so the watch gets close enough to the reader.
Most of the time they are holding their phone in their other hand which makes the whole thing extra silly and unnecessary.
I still think this is a pretty cool project.
Re: Hacking a Casio F-91W digital watch (2023)
#39I wish there were a way to put the chip & antenna inside (or behind?) the watch casing. While this is really impressive, putting something in front of the faceplate breaks the great F-91W look and feel for me.
Projects like ollee Watch seem to be able to stash it behind the front crystal or underneath the LCD.
Ollee does that by replacing the original PCB. In this project the movement is kept original.
I recall the blog n-o-d-e did successfully put an NFC chip inside while also retaining the default PCB, so there is at least some free space in the case...
Re: Hacking a Casio F-91W digital watch (2023)
#40This is a really cool hack, and I wish I could pay for things with a dumb watch. It's just the right level of useful and silly to be up my alley. But the article, as others have mentioned, is a little off. The author did not "invent" the guess-and-check method for verifying resonance. That's been a staple of radio since the beginning, which is why original tuner dials were actually variable capacitors
> Therefore, an ideal antenna should consist of a 22.12 metre long wire, but by convention fractions of λ-lambda (λ/2, λ/4, λ/8, λ/16, etc.) are opportunely chosen.
This sentence is confused enough to be incorrect. λ/2 is generally preferred as an antenna length (standard dipole configuration) because it will resonate at the appropriate frequency with desirable standing wave characteristics (current maximum and zero voltage at input, voltage maximum and current minimum at ends). λ/4 can be used as a half-dipole, but it requires a ground plane to resonate properly. There are also arguments to be made for a 5λ/8 antenna, but none that I'm aware of for λ/8 or λ/16.
In practice for small antennas, physical length and electrical length are only tenuously related, so it's a matter of creating a circuit that acts like an antenna of the chosen length.