CES 2014: Sports sensor 'judges your golf swing'
6 January 2014 Last updated at 15:49 GMT
Being careful not to cause injury at the packed CES preview event, Zepp's Jason Fass demonstrated his company's sports sensor to the BBC's Dave Lee.
The small yellow device fits to various pieces of sports equipment, such as a golf club, tennis racquet and baseball bat.
Using Bluetooth, the sensor transmits analysis of movement to a tablet app, giving feedback immediately.
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