welcome to the seg electronics megamarket in shenzen.and it's here that you come to buy anything and everything electronic. this is also where you can bulk buy new components for manufacturing a new device. this is we get lithium ion batteries for your laptops, smartphones — anything, really. but what if you didn't need these at all? we created the first battery—free phone, which harvests enough power from ambient light and ambient rf signal so that we can completely power the whole phone byjust ambient rf energy. and elemental batteries. you can make a phone call to another cell phone or another landline. by stripping back components to the bare minimum, vamsi and his team have successfully made calls over skype. they take advantage of something called analogue backscatter, which reflects pre—existing waves found all around us to communicate a message. right now this only works in the lab, but the team are working on improving its range beyond ten metres. for the moment, batteries do thejob. but we all wish we could charge that little b