So you want to build your own smartwatch? In the past few months, we have covered plenty of guides that show you how to do that. benhur.goncalves’s Arduino Pedometer Watch is quite interesting as well. He used a sensor board with a compass, pressure/altitude/temperature sensors, an accelerometer, and gyroscope to complete this project.
The above video just gives you a quick look at this Arduino Pedometer Watch. More information is available here.