The power generating dog leash is the work of Goddard Technologies, and as you’d guess, it is quite different from the dog leashes we are used to seeing. This one has three high intensity LEDs and a safety button that sets off an emergency tone. Other features include an ergonomically designed handle that lets you have a comfortable grip and a quick lock brake to stop the recoil of the leash. The more interesting part of course, is the power generating the leash does.
Energy generated by the dog pulling at the leash and by the recoil is harvested in this leash, rather than let it go waste. A gear train mechanism spins a generator everytime the leash hub spins. The energy so generated is sent to lithium ion batteries, which in turn power the LEDs and the emergency tone.
Once the batteries are fully charged, they could power the LEDs for nearly 6 hours, but considering the low voltage cut off level, a more realistic figure would put the time at about 3 hours.