A product design student at University of Dundee in the UK, Fraser Spowart, has developed a prototype dumbbell curl counter that can inform friends and competitors

The offline mode helps users with the full procedure of the bicep curl. The online mode can be activated after the user is comfortable with the bicep curl.
Tweets are sent once the user begins exercise. Once the session is completed, tweets are sent again to convey the close of the session.
Source-Medindia