There are lots of apps and gadgets to track your fitness progress. However, if you'd like to keep that data private, you need to roll your own. Instructables user gramsky shows how to create a system that tracks your movement with an Arduino.
The main feature of the device allows you to track how much time you spend indoors throughout the day, but it also tracks all of your movement. It uses an Arduino Uno, Arduino WiFi shield, GPS, thermometer, accelerometer and a few other tools. We all know spending more time outdoors is good for your health, and this device gives you a better idea of how much time you're actually spending outside. Head over to Instructables to see how to make this for yourself.