I was working out with a friend and his apple watch would automatically track his exercise via his heartbeat. I wanted a similar thing so that I wouldn't have to remember numbers which I'm really bad at when I'm running.
How I built it
I average the accelerator data in order to determine if it's in enough motion and if it's in enough motion i start the clock.
Challenges I ran into
The accelerometer in pebble produced really weird values for acceleration that I found very confusing. Furthermore the AUR had a lot of issues this weekend and that made it hard to get the pebble dev environment set up.