“Radio frequency energy harvesting” might sound like snake oil — Free energy, pulled out of thin air? Yeah, right! — but the idea of using radio waves to transmit power has been around for more than a century and is finally coming into its own with the Internet of Things. Between Wi-Fi, Bluetooth, cell phones and myriad other wireless signals, there are plenty of ambient RF sources to draw from. And even though only small amounts of energy can be reclaimed this way, it doesn’t take much to keep a simple sensor or actuator running.

Continue reading… “Freevolt: Radio Frequency Energy Harvesting”