How do Fitness Trackers Work?

How do fitness wearables keep track of so many different things, and what are their limitations? Freshbooks message: Head over to http://freshbooks.com/techquickie and don’t forget to enter Tech Quickie in the “How Did You Hear About Us” section when signing up for your free trial. Follow: http://twitter.com/linustech Join the community: http://linustechtips.com source