A couple of weeks ago I showed you some modifications for the famous Casio F-91W digital watch, and after a few ideas from you, and a bit of experimenting, I'm back with two further mods.

- Youtube link
- mirror
- Torrent
- Keybase mirror


The first mod is something a few of you pointed me to after the last video. It basically modifies the polarizing film on the LCD, and inverts the colours of the screen.

Pretty simple, but it looks nice, and definitely gives the watch a unique aesthetic.


The next screen mod is something I've not seen anywhere else, and basically makes the screen translucent, so you can see the innards of the watch, behind the numbers.

It especially looks cool in low light when using the LED, because it lights up everything behind the screen.


The screen assemblies on these watches are split into 4 main parts. On top you have the polarizing light filter, then the actual LCD encased in glass. Below that there is a mirrored film, and at the bottom is an opaque piece of white plastic, which I'm guessing is to help screen contrast.

To invert the screen, you need to get a sharp scalpel or craft knife, and carefully remove the top layer, and any adhesive residue underneath. Be sure not to scratch or break the fragile piece of glass beneath it. Then the new piece of polarizing film goes on top, placed so that it inverts the colours.

To make the screen translucent, you remove just the bottom two layers, and replace it with something like tracing paper. You could make it fully transparent, but the contrast between the numbers on the screen and the inside of the case is not good for readability.


Like the previous mods, I've made some of these, and if you want to get your hands on one, and also help support NODE at the same time, they're in the shop now. I know the others sold out quickly, so if that happens again, I will be making a lot more.

This time, I've gone with simpler options. Both screen mods are available with a clear watch face, and I've swapped the standard green LED for a custom bright white one. These ones don't include the NFC chip, because it didn't look very good in this configuration.