We're surrounded by electromagnetic fields almost everywhere these days. Just because they're almost imperceptible doesn't mean they can't be used as a source of energy though. One student in Germany recently built the Electromagnetic Harvester, a small box that allegedly charges an AA battery using just the electromagnetic fields given off by the likes of power lines, vehicles and electronic gadgets.
Dennis Siegel, a digital media student at the University of the Arts in Bremen, designed the handheld charger as a way to recover some of the energy from these electromagnetic fields. It may sound a little sketchy, but it's an idea that many researchers, including a team at Georgia Tech, have been exploring for years. The main issue with this form of energy collection is the amount of power it generates tends to be incredibly small, which might explain why it takes a full day for the Electromagnetic Harvester to charge a single AA battery.
According to Siegel, using the harvester involves simply holding it up to anything with an electromagnetic field – a cell phone, a coffee maker, a commuter train, etc. Once it enters a strong enough field, a red LED will light up to indicate it is charging. It also has a magnet on the back to leave it attached near an EMF source and can charge from the combined fields of living things, like when a person pets a dog. Seigel designed two different versions of the harvester: one for frequencies below 100Hz (like those found in electricity mains) and one for frequencies above 100Hz (like those found in Bluetooth, WLAN, and radio broadcasts).
But don't start thinking this signals the end of charging devices through ordinary wall sockets just yet. While the potential for this type of technology being used to charge very low-powered devices like wireless sensors or RFID tags is there, we remain very skeptical about any practical consumer electronics applications. Aside from not being able to generate enough power for a typical smartphone user, Siegel has yet to reveal any specifics on how his take on the ambient energy charging device works – only that it involves "coils and high frequency diodes." So while it's great in theory, we'll take these claims with a grain of salt.
Check out the video below to see some of the examples of how Siegel sees the Electromagnetic Harvester being used throughout a typical day.
Source: Dennis Siegel
