There are several similar projects (and now an official Kobo accessory) to enable Bluetooth page turners, but I wanted to use the thing I already have that is already on my wrist!
Unlike other page turners, which communicate with the Kobo as Bluetooth peripherals, this inverts the roles. This is because Apple's Core Bluetooth library does not allow Apple Watch to act as a peripheral. Hence, the Nickel plugin includes a Bluetooth peripheral process, thereby enabling an Apple Watch to communicate with it. This involved reverse engineering a fair amount of Kobo Bluetooth code.
Right now this only supports MediaTek-based devices (Clara BW/Colour, Libra Colour, Elipsa 2E). It probably would be straight forward to implement for older devices (it might not even need the reverse engineer bit), but I do not have one around to build/test on.
https://github.com/quicklywilliam/KoboWatchRemote
