Casio F-91W, Going Dark

The Casio F-91W is easily one of the most iconic and popular watches worldwide. But what’s cool about having the same exact thing as millions of other people? Not much, unless of course you modify it to make it your own. That’s exactly what [Gautchh] did to their beloved watch. Between permanent dark mode, stereo blue LED backlights, and a new strap, this timepiece really stands out from the crowd.

Once [Gautchh] got the watch open, the first order of business was to re-polarize the LCD with a different film so the digits are light and the background is dark. This watch ships with a single green backlight LED that’s fairly faint, so [Gautchh] upgraded it to bright blue and added a second 1206 LED in parallel on the other side of the readout. Finally, they replaced the rubber strap with something less likely to chafe.

We think dark mode looks great, though [Gautchh] says it requires a little bit of training to hold your wrist just right to make it readable. They make these mods look easy, but they likely aren’t for the faint of heart. If you want to give it a shot, there are good step-by-step instructions and several pictures to help out.

We’ve seen a lot of Casio F-91W projects over the years, including a method for waterproofing the internals. If you have a lot of love for this watch, why not make a giant version?

It’s Time For Watch Clocks To Make A Comeback

Along with all the colorful, geometric influence of Memphis design everywhere, giant wristwatch clocks were one of our favorite things about the 80s. We always wanted one, and frankly, we still do. Evidently, so did [Kothe]. But instead of some splashy Swatch-esque style, [Kothe] went the nerdy route by building a giant Casio F-91W to hang on the wall.

Not only does it look fantastic, it has the full functionality of the original from the alarm to the stopwatch to the backlit screen. Well, everything but the water resistance. The case is 3D-printed, as are the buckle and the buttons. [Kothe] might have printed the straps, but they were too big for the bed. Instead, they are made of laser-cut foam and engraved with all the details.

Inside there’s a 7″ touch display, a real-time clock module, and an Arduino Mega to make everything tick. To make each of the printed buttons work, [Kothe] cleverly extended a touch sensor module’s input pad with some copper tape. We think this could only be more awesome if it were modeled after one of Casio’s calculator watches, but that might be asking too much. Take a few seconds to watch the demo after the break.

Prefer your clocks less clock-like? Get a handle on the inner workings of this slot machine-based stunner.

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