In the US, inventories were draining and firms such as Ultralife Batteries were working round the clock to produce ...

And it’s getting to the point where the accessories, particularly the battery charging trays, are getting bulkier than the radios. With that in mind, [Mads Hobye] decided to slim down his ...

it never needs to charge and doesn't have a battery. Instead, it pulls power from ambient light and radio waves. Follow Tech Insider: On Facebook More from Tech Researchers at the University of ...