Attach lightweight piezo benders to slender, brightly colored fan-like "flaps" - paste the flaps all over the inside of an ordinary highway tunnel or under bridges - every time a car passes by, it generates a small curl of wind which is tapped by the piezo-flaps.
This comes down to sneakily stealing energy from ordinary car owners. Cities with deficits may be interested.
Sell it as some post-modern art project ("embellishing post-industrial urban traffic's energy flows") and bingo!-- django, Aug 15 2004 <link from Around TUIT delete when done> http://www.piezo.com/The FAQs helped me a lot [Around TUIT, Oct 04 2004, last modified Oct 05 2004] "The new Carsgothrough Tunnel has generated 30 milliamps since the instillation of state of the art Piezoelectic generators last week!"-- Cats Whiskers, Aug 15 2004 great gin though.-- po, Aug 15 2004 Nice. Humanity returns to the biocycle. Excellent! Croissants to you for your baking balancing act. Couldn't piezos also be put under the road?-- Around TUIT, Aug 15 2004 Piezo salt crystals in a salt mill: after you start, it grinds itself.-- FarmerJohn, Aug 15 2004 Oh boy, not the piezo meme again!-- krelnik, Aug 17 2004 How the hell did this idea get 9 bits of bread? [Cats] is correct - energy output will be approximately zero, give or take a couple of Watts.-- suctionpad, Aug 17 2004 How bizar, I only see 6 piezo ideas here in the category. Why all the fuzz?
[krelnik] as you can see, piezo is obviously one of the least debated topics ("memes" duh) at the Halfbakery.
Moreover, why would anyone think that a tunnel full of piezofans would only generate a few miliamps?
"" Q. How much electrical power can I get out of one piezo sheet in principle? A. Assuming that we stretch a PSI-5A (1.5" x 2.5" x .0075") sheet to ±500 microstrains quasistatically at a frequency just below its fundamental longitudinal resonance of 15 KHz, and that we collect 100% of the stored electrical energy at its height twice per cycle we would get approximately 9 watts of electrical power from the sheet. The mechanical energy input under these assumptions would be in excess of 100 watts. Resonant designs can be considerably more efficient. However, the mechanical apparatus for achieving the above mentioned 15 KHz high strain excitation is not available, and there is no known electronic method for extracting 100% of the available energy.""-- django, Aug 18 2004 I thought piezo was quite hard to get hold of, wouldn't this tunnel be hugely expensive? Why not just have big foam covered turnstyles that the cars hit as they pass making a turbine turn?-- harderthanjesus, Aug 18 2004 random, halfbakery