Scavenging ambient electromagnetic energy

energy_harvesting_from_radio_waves

At this very moment, unseen radio waves are bouncing off almost everything that surrounds you. Emitted by everything from radio and TV stations to cell phone networks and satellites, these waves are full of unharnessed energy. That is, until now. Researchers at the Georgia Tech School of Electrical and Computer Engineering have been working diligently to harness this unused energy, and recently unveiled their new antenna technology at the IEEE Antennas and Propagation Symposium.

The team, led by professor [Manos Tentzeris] has been working to develop ultra-wideband antennas to tap into the energy all around us. Using printers filled with a specially-formulated ink compound, they have been able to print these antennas on paper and polymer substrates. The antennas can harness energy stored in radio frequencies ranging from 100 MHz all the way up to 60 GHz, depending on the printing medium.

The team can currently power temperature sensors using television signals, and is preparing a demo in which they will power a microcontroller simply by holding it up in the air. The technology is still in its infancy, but the list of applications is almost endless. We doubt you’ll be powering your TV with this technology any time soon, but it definitely holds promise for things such as wireless sensor mesh networks and the like.

[Thanks, morganism]

Waterfall signal visualizer from Arduino and cellphone LCD

[Leigh] is a HAM operator (you may know him as wa5znu). He is familiar with a signal visualization tool called a waterfall which plots signal strength and frequency over time. He wanted to build his own waterfall and ended up with this Arduino-based version which he calls Cascata. Cascata means waterfall in Italian which meshes nicely with Arduino’s country of origin

The display he chose is a Nokia LCD shield from SparkFun. It’s easy to plug in and there were already libraries available to drive the display. The audio input just connects to a headphone plug (you can just make it out at the bottom right in the image above) using some electrical tape. A free-formed resistor divider ensures that the signal is within a measurable range. [Leigh] found that signal noise was a bit of a problem but was able to improve his results by adding a capacitor to the Arduino headers between the VREF and GND pins.

See it in action after the break.

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