Remember potato batteries? This site claims 880 millivolts. http://www.science-projects-resources.com/how-to-make-a-potato-battery.html
On Sep 10, 2009, at 4:59 PM, Paul Jost wrote: > A couple of hundred millivolts at microamp levels or less from a > tree seems very reasonable. Low potential energy and charge storage > is present in anything with unbalanced ion concentrations. Maybe > ionic charge could be a force that helps with sap flow up the > world's tallest trees? Only one of a kind custom semiconductors can > run off that minute of an energy source and they spend most of their > time trickle charging the input capacitor and then coming out of > sleep/standby mode only briefly before shutting down again for a > proportionately long time. It is unlikely that any real commercial > application could be derived from this for at least several years. > > PJ > > On Thu, Sep 10, 2009 at 3:34 PM, DON BERTOLETTE > <[email protected]> wrote: > Steve- > In rereading the initial post below, > "A study last year from the Massachusetts Institute of Technology > found that plants generate a voltage of up to 200 millivolts when > one electrode is placed in a plant and the other in the surrounding > soil." > it seems that indeed, the electricity is of little magnitude, > effective perhaps only in nano-technology and even more > speculatively, as a measure of tree health. It's this last item that > held my interest! > -Don > Subject: [ENTS] Re: tree power!!! > Date: Thu, 10 Sep 2009 05:52:44 -0500 > From: [email protected] > To: [email protected]; [email protected] > > Pardon my skepticism here about this...trees can be conductors of > electricity (dangers of power line contact; also lightning strike > patterns) but I'm a little skeptical regarding the sustainable > transmission of electricity of any magnitude. > > Steve Springer > > From: [email protected] on behalf of DON BERTOLETTE > Sent: Wed 9/9/2009 10:49 PM > To: [email protected] > Subject: [ENTS] Re: tree power!!! > > PJ- > I'll bet there are differences between species... > -Don > > Date: Wed, 9 Sep 2009 17:02:32 -0500 > Subject: [ENTS] tree power!!! > From: [email protected] > To: [email protected] > > ENTS, > > Here is a "must read" on trees from the U of Washington: > http://uwnews.org/article.asp?articleID=51869 > > PJ > > > University of Washington > Electrical engineers Babak Parviz and Brian Otis and undergraduate > student Carlton Himes (right to left) demonstrate a circuit that > runs entirely off tree power. > Sept. 8, 2009 | Science | Technology > Electrical circuit runs entirely off power in trees > Hannah Hickey [email protected] > > > University of Washington > The custom circuit is able to store up enough voltage from trees to > run a low-power sensor. > > > You've heard about flower power. What about tree power? It turns out > that it's there, in small but measurable quantities. There's enough > power in trees for University of Washington researchers to run an > electronic circuit, according to results to be published in an > upcoming issue of the Institute of Electrical and Electronics > Engineers' Transactions on Nanotechnology. "As far as we know this > is the first peer-reviewed paper of someone powering something > entirely by sticking electrodes into a tree," said co-author Babak > Parviz, a UW associate professor of electrical engineering. > A study last year from the Massachusetts Institute of Technology > found that plants generate a voltage of up to 200 millivolts when > one electrode is placed in a plant and the other in the surrounding > soil. Those researchers are working with a company, Voltree, to > develop forest sensors that exploit this new power source. > The UW team sought to further academic research in the field of tree > power by building circuits to run off that energy. They successfully > ran a custom circuit solely off tree power. > Co-author Carlton Himes, a UW undergraduate student, spent last > summer exploring likely sites. Hooking nails to trees and connecting > a voltmeter, he found that bigleaf maples, common on the UW campus, > generate a steady voltage of up to a few hundred millivolts. > The UW team next built a device that could run on the available > power. Co-author Brian Otis, a UW assistant professor of electrical > engineering, led the development of a boost converter, a device that > takes a low incoming voltage and stores it to produce a greater > output. His team's custom boost converter works for input voltages > of as little as 20 millivolts (a millivolt is one-thousandth of a > volt), an input voltage lower than any existing such device. It > produces an output voltage of 1.1 volts, enough to run low-power > sensors. > The UW circuit is built from parts measuring 130 nanometers and it > consumes on average just 10 nanowatts of power during operation (a > nanowatt is one billionth of a watt). > "Normal electronics are not going to run on the types of voltages > and currents that we get out of a tree. But the nanoscale is not > just in size, but also in the energy and power consumption," Parviz > said. > "As new generations of technology come online," he added, "I think > it's warranted to look back at what's doable or what's not doable in > terms of a power source." > Despite using special low-power devices, the boost converter and > other electronics would spend most of their time in sleep mode in > order to conserve energy, creating a complication. > "If everything goes to sleep, the system will never wake up," Otis > said. > To solve this problem Otis' team built a clock that runs > continuously on 1 nanowatt, about a thousandth the power required to > run a wristwatch, and when turned on operates at 350 millivolts, > about a quarter the voltage in an AA battery. The low-power clock > produces an electrical pulse once every few seconds, allowing a > periodic wakeup of the system. > The tree-power phenomenon is different from the popular potato or > lemon experiment, in which two different metals react with the food > to create an electric potential difference that causes a current to > flow. > "We specifically didn't want to confuse this effect with the potato > effect, so we used the same metal for both electrodes," Parviz said. > Tree power is unlikely to replace solar power for most applications, > Parviz admits. But the system could provide a low-cost option for > powering tree sensors that might be used to detect environmental > conditions or forest fires. The electronic output could also be used > to gauge a tree's health. > "It's not exactly established where these voltages come from. But > there seems to be some signaling in trees, similar to what happens > in the human body but with slower speed," Parviz said. "I'm > interested in applying our results as a way of investigating what > the tree is doing. When you go to the doctor, the first thing that > they measure is your pulse. We don't really have something similar > for trees." > Other co-authors are Eric Carlson and Ryan Ricchiuti of the UW. The > research was funded in part by the National Science Foundation. > ### > > For more information, contact Parviz at 206-616-4038 or > [email protected] > or Otis at 206-616-5998 or [email protected]. > > > > Get back to school stuff for them and cashback for you. Try Bing now. > > > > > > Windows Live: Make it easier for your friends to see what you’re up > to on Facebook. Find out more. > > > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
