The 36-year-old Casio F-91W just got its first major upgrade - and it's not from Casio. The Ollee Watch One is a $55 DIY kit that adds Bluetooth connectivity, step tracking, and retro games to classic Casio digital watches without requiring any soldering skills. While it won't replace your Apple Watch, it bridges the gap between vintage charm and modern convenience.
The legendary Casio F-91W has remained virtually unchanged since 1989, becoming a cultural icon worn by everyone from presidents to terrorists. Now a startup called Ollee is giving this $20 timepiece its first real makeover with a drop-in upgrade that doesn't require any electronics expertise. The Ollee Watch One is a replacement mainboard that transforms six different Casio digital watch models into quasi-smart devices. For $54.99, you get Bluetooth connectivity, step tracking, games, and a customizable LED backlight that can even serve as a flashlight. The installation process takes about six minutes according to Ollee's demonstration video, requiring only the ability to remove a few screws and clips - no soldering iron in sight. The company is clearly betting on the massive nostalgia factor around these watches. The F-91W alone has sold over 100 million units since launch, making it one of the most popular timepieces ever created. Its minimalist design and legendary durability have made it a favorite among military personnel, outdoor enthusiasts, and fashion-conscious millennials alike. What makes the Ollee upgrade compelling is how it respects the original watch's character while adding genuinely useful features. The replacement board includes an accelerometer for step counting, a temperature sensor, and an improved buzzer that can alert you when you hit fitness goals set through the accompanying iOS and Android app. The color-changing backlight is particularly clever - you can customize it through the app or cycle through different colors manually. But perhaps the most charming addition is gaming. Yes, you can now play a simplified version of Blackjack or a ball-bouncing game called Ping on the same segmented LCD display that's been showing the time since the Reagan administration. The games work within the constraints of the original seven-segment display, creating an almost Game Boy-like retro gaming experience on your wrist. The upgrade maintains the watch's core functionality while adding world time support and five timer presets. Bluetooth Low Energy handles the smartphone connectivity, automatically syncing the time and allowing you to customize settings without button-mashing through tiny menus. Of course, there are trade-offs. The legendary seven-year battery life gets reduced to about 10 months - still impressive by smartwatch standards but a significant drop from the original's endurance marathon. There's no notification support, and you're still limited to the basic segmented display that can't show complex graphics or full text messages. The timing feels perfect though. As fatigue sets in and people yearn for simpler tech, the Ollee upgrade offers a middle ground. You get some smart features without the complexity, constant notifications, or daily charging requirements of modern wearables. The company is selling two versions: the DIY kit for existing Casio owners and pre-upgraded watches for $99.99. The latter are currently sold out, suggesting strong demand from people who want the upgrade without the installation hassle. Compatible models include the F-91W, A158W, F-84W, A159W, A171W, and W-59. This represents a clever business model - rather than trying to create an entirely new smartwatch category, Ollee is building on decades of design refinement and cultural cachet. The F-91W's form factor, button layout, and display technology have been perfected over 36 years of production. Why start from scratch when you can enhance a proven winner?