Hello there,
recently I completed my first prototype, home made smartwatch.
Using old nokia 5110 lcd screen.
Here's how it looks :
And You can Play a simple game like :
and it has a cool velcro strap for easy and tight fitting.
The smartwatch is programmed using C++ and is based on avr attmega328 based microcontroller, namely arduino nano. The watch presently has a capability to set brightness, set time (of course) , run a simple survival game,and also supports Bluetooth. It can connect to your smartphone and check for notifications,messages and missed calls.It has a simple to use and understand GUI. More features can be added easily by reprogramming the watch.
It costed around 16$. And remember that I am still in class XII and I made it without using any kits or any professional aids.
You can see a small demo of the smartwatch on :