Microchip Powered by Body Heat

An anonymous reader writes "MIT and Texas Instruments researchers have designed a chip that they say could be up to 10 times more energy efficient than current technology. The chip's power consumption is so low that devices with the chip may even be able to be recharged using the owner's body heat." The intent is to use these in medical applications like pacemakers where one would expect to have the free power source.

Powered by heat?

[Bazman]

Two things spring to mind:

  1. If it's powered by your body heat, it's going to make you colder...

  2. Don't you need a temperature _gradient_ to get useful power out of heat?

cochlear implants ...

[constantnormal]

... would seem to be a much more likely implanted medical device than pacemakers to use this technology. Having a pair of fully-implanted, self-powered devices that independently provide sound to each ear would seem to be a huge step forward, and readily achievable with this sort of technology.

And with a generation rapidly driving themselves deaf via iPods, a technological solution like this would seem to be appropriate and is arriving just in time.

While I don't know what kind of voltages and currents a pacemaker uses to regulate heart activity, it would seem a lot more likely that a cochlear implant would use less. Plus, there's a lot less downside risk if the device malfunctions.

Re:Powered by heat?

[EaglemanBSA]

1.) Yes, it will indeed take heat from your body, but it would do nothing more than force the heart to pump a little more blood to maintain your body temperature. Many people don't know that one of the many functions your cardiovascular system performs is temperature control - it's one of the world's most complex heat exchangers. You introduce a small enough cold sink, and it will heat that area of the body up to make up for it. 2.) That depends on how they're getting power from the heat - if it's powering a heat engine and runs off heat flux, then yes, they would need a temperature gradient (which isn't that hard to get anyhow - put the cold sink near the epidermis and the hot sink near your heart/brain/etc.). If they're using the heat to run a small chemical reaction, then no, they probably wouldn't need a temperature gradient (e.g.: when using two dissimilar metals to generate a charge, the absolute temperature is directly proportional to the reaction rate). I'm currently studying the thermodynamics of the body for my master's, it's a very interesting subject.

Re:cochlear implants ...

[InterGuru]

I have a pacemaker. The manufacturer ( St. Jude ) claims that the battery will last 6-8 years.

In the old days pacemakers used a plutonium powered thermoelectric battery. This lasted forever, or about 25,000 years to be precise. They are now banned in the US because of the danger that the plutonium could be released in some way, such as a plane crash, a gunshot wound, or crematorium . They actually had to dig up some bodies because the undertaker did not remove the battery.