BBC NEWS
A tiny generator powered by natural vibrations could soon be helping keep heart pacemakers working.
Created by scientists at the University of Southampton, the generator has been developed to power devices where replacing batteries is very difficult.
The device is expected initially to be used to power wireless sensors on equipment in manufacturing plants.
The generator's creators say the generator is up to 10 times more efficient than similar devices.
Power packed
The tiny device, which is less than one cubic centimetre in size, uses vibrations in the world around it to make magnets on a cantilever at the heart of the device wobble to generate power.
Although the generator produces only microwatts this was more than enough to power sensors attached to machines in manufacturing plants, said Dr Steve Beeby, from the University of Southampton, who led development of the device.
"The big advantage of wireless sensor systems is that by removing wires and batteries, there is the potential for embedding sensors in previously inaccessible locations," he said.
Using the tiny generator also made it possible to use larger numbers of sensors because there was no longer the need to visit them to replace or recharge batteries, said Dr Beeby.
The generator was developed to sit inside air compressors but, said Dr Beeby, it could find a future role in self-powered medical implants such as pacemakers.
In a pacemaker the beating of the human heart would be strong enough to keep the magnets inside the device wobbling.
It could also be used to power sensors attached to road and rail bridges to monitor the health of such structures.
Work on the project was funded by the EU as part of the 14.3m euros (£9.67m) Vibration Energy Scavenging (Vibes) project that is looking at how to use environmental vibrations to generate power.
*OK ... why hasn't this been done ALREADY - like a DECADE ago ??? The minute samarium-cobalt and NIB magnets were availible the old lightbulb should have lit across the globe, especially with medical techs. Wobble a strong magnet near conductive coils and you get ELECTRICITY. For pacemakers, brain stimulators (Parkinsons & other ailments) and automatic medicine dispensers the amount of electricity needed is very small. The "wobbler" can keep a super-cap fully charged, no real high-tech stuff involved. Cheap, efficient, effective.
There's ANOTHER unexploited "free" energy source - the radio waves which permeate every millimeter of this planet. From AM broadcasters through Wi-Fi, we're constantly bathed in RF energy from communications equipment and power lines.
If you're of a certain age, you'll remember those "crystal radio" kits (pre-fab units were also sold). Essentially a slug-tunable antenna (occasionally a fine-tuner was incorporated), a germanium whisker diode and a crystal earphone. The RF from strong AM stations was half-rectified, thus demodulated, and the resultant AF was sent to the earpiece. They were tinny, but loud enough to hear across the room if you took the earpiece out of your ear.
This represented rather a lot of power (in biological terms anyway). A power unit can easily be constructed along simiar lines and you don't even want the tuning circuit. A coil with an antenna a few feet long, a diode (or more if you want to salvage the other sideband) and a super-cap. Should be able to scavenge usable power from 60 Hz hum up into the VHF band. Scavenging UHF->microwave might require a second circuit to optimize power capture.
There's plenty OF it, even at the poles or the middle of the pacific ocean. The only 'dead zone' might be a deep mine with a lot of iron ore around - but even then it would get military VLF/ELF transmissions. The whole thing would be the size of a 1/2-AA battery and weigh a few grams. The antenna lead, if desireable, could be strung into the abdominal cavity.
Again, MORE than enough power to run pacemakers and such. If anything, you'd have to include a zener to clip spikes cause by nearby lighting and electrically noisy motors. A completely passive device, no moving parts at all. Might not work on Mars ... but then nothing's perfect.