First, our phones became smarter. Next, our watches decided to do more than just tell time. I imagine it was right about then that makers decided to take on the challenge of hacking these newly found smart devices on our wrists.
The vast majority of hybrid smartwatches made by Skagen, Fossil, and the like, use Soprod micromotors. Others tend to use something based on the same reference board design.
Knowing this, the OpenChronograph mainboard intends to be a a programmable drop-in replacement for most commercial smartwatches. This kit comes with a mainboard and a USB pogo serial programmer, both of which are compatible with the Arduino IDE.
You can find instructions and details on the Github as well. A drop-in board like this allows you to get around the closed nature of hybrid smartwatch design, opening it up for designs from the maker community!