I bought a G-Shock that does that. It is very consistent for its distance, because it uses GPS satellites. Well worth the $800CDN that I paid.
I want to thank you for the thread and the discussion. I agree that the bikes are not ready for prime time. but the concept is quite interesting since using hydrogen for fuel saves a lot of weight as compared to lithium based batteries.
My folding electric bike which has a 750w/100w peak motor and 15ah 48v battery weighs approximately 80 pounds, nearly twice what the bikes in the article weigh. But of course, it will get to 28mph on the flat with no problem and was built with comfort and toughness in mind.
The batteries on my bikes weigh approximately 10 pounds and contain approximately the same energy as 28 grams of hydrogen. This system is all about saving weight. People do spend a lot to save a few grams of weight on a bicycle.
I am curious about your G-shock watch.