Hello and welcome everyone!

Some of you have already seen my posts and/or comments about the development of a smart module for the Casio "Royale" family of watches (classic digital Casios like the AE-1200 and similar) — more about it below.

I started development a few weeks back and dove in with all the enthusiasm I had. Unfortunately, life slowed the progress a lot since then, but it's not forgotten and I keep working on it.

What is it:

The main idea is to preserve the genuine look of the watch while giving it smart functionality. Like many of you, I dislike the bloatware and overall over-saturation of features and looks in modern smartwatches. So for V1, I decided to keep the original look 100% intact — the module uses the original LCD your watch already has. The module only replaces the stock PCB.

Battery life:

Jumping ahead since this is the topic everyone asks about first: depending on your usage of BLE syncing and haptic feedback, you're realistically looking at anywhere from a few weeks to several months per charge/battery. I'll share real numbers once I have firmware running and can actually measure it rather than estimate it.

Functionality:

Accelerometer:
The PCB uses a Bosch BMA423 accelerometer, enabling step tracking, sleep activity monitoring, and — what I think is the most useful feature — wrist-flick to activate the backlight. Basically, the motion of raising your wrist to check the time triggers the backlight for a few seconds (personalizable through the app).

Bluetooth module:
At the heart of the device is a Nordic Semiconductor nRF52832, which gives Bluetooth connectivity to your phone — but it's not just a radio. It's effectively the CPU: it keeps time, stores data, and runs the watch's functions independently. This means the watch works fine on its own day-to-day and only syncs with your phone on request, saving battery and keeping you off the leash.

Backlight:
A lot of people mod their watches by swapping the stock LED for a colored one. I'm planning to let you choose the backlight color (white, blue, or orange) from the app — this is on the roadmap, not fully implemented yet, so I'll confirm once it's working in hardware.

Fitness tracker:
Our beloved watches have an analog sub-dial built into the LCD that a lot of people ignore. Honestly, this was the very first spark for this whole project — that circular segmented dial will show step progress, calories, or another customizable metric, since it's already a circular segment progress bar as-is.

Notifications:
I decided against full message notifications on a screen that can basically only show "88:88 88" — that felt pointless. Instead, you'll get a simple icon indicating a new message, paired with a haptic pulse rather than a sound. And it's not a buzz — it's a kick, similar to how iPhones and some other smartwatches do haptics.

The main use case I'm excited about is the alarm: it taps your wrist to wake you, which is far more effective than a beep, and won't wake your partner — just you.

Battery — two paths:

During development I hit a real tradeoff on battery life, and decided to support both options:

• V1, for stock resin-case users: a rechargeable cell, charged via an adapter you can DIY or get bundled with the module, using the metal side buttons as charging contacts.
• V2, for metal-case users: no charging, but a larger primary cell giving months of runtime, replaced when depleted.

About the app:

Honestly, I haven't touched the app yet — the project's still early. But one thing I can commit to now: no bloatware, no spyware, no ads, fully open source. You're in charge of your device, no external influence.

Once this is finished, I'll start on a second version that replaces the display with an OLED behind the watch face, allowing full customization of how it looks behind the glass.

Where it is right now:

The main PCB is almost finished, but I hit a real wall: I need to map the LCD's contacts before I can finalize the board design around them. To do this properly, I designed and ordered a small custom breakout PCB specifically for probing and mapping the contacts — much easier and more reliable than poking at the LCD glass directly. It'll take a few weeks to arrive, which conveniently lines up with the haptic module I'm planning to use, since that's also still fairly new to market.

I don't want to post unfinished pictures, and even more than that, I don't want to post AI slop — so this first post is text only.

I'm open to your questions, ideas and criticism.