Fraser Spowart, a product design student at University of Dundee in the UK, has built a prototype dumbbell curl counter that can tweet your exercise patterns to friends and competitors. 
We can see a miniaturized version of the Tweet_Fit adapted for other repetitive exercise routines.
From the designer:
The device has two main functions, an offline and online mode. The offline mode has been designed to guide the user through the perfect bicep curl. Once this is mastered the online mode can be activated.
To activate the online mode you simply pick up the dumbbell with the device attached, doing this will send a message to your twitter feed indicating you have began to exercise. You will be notified that the message has been sent by green lights flashing. Once you have finished your exercise and put the dumbbell down again another tweet will be sent indicating the end of your exercise. Red lights will flash to indicate a second tweet has been sent.
Link: Tweet_Fit info page…
(hat tip: Engadget)