This is an incredible feat. It runs on 3.5uW, and the homemade cellphone I built last year with off-the-shelf components drew 2A when syncing with GSM antennas

This is an incredible feat. It runs on 3.5uW, and the homemade cellphone I built last year with off-the-shelf components drew 2A when syncing with GSM antennas. Some people don't realize it, but GSM is very expensive power-wise, especially on boot when it has to find antennas. Having a device that can be solar powered or even with ambient radios is extremely useful! Right now the battery-free phone needs a custom base station to transmit and receive calls. But the team says there's no reason why the technology couldn't be integrated into standard mobile network infrastructure Well, there's the trick. But an awesome proof of concept nonetheless