Saturday, June 16, 2012

Energy Harvester Converts Walking Movement Into Electricity for Carried Gadgets

Gadget of the year?

Hat tip to Chris Sickham at IOIL SciTech in
Device powers gadgets through walking
 
A new wearable "energy harvester" that converts walking body movement into electricity for gadgets was unveiled in Smart Materials and Structures (Wikipedia), July issue, Smart Materials and Structures Volume 21 Number 7, Michele Pozzi et al 2012 Smart Mater. Struct. 21 075023 doi:10.1088/0964-1726/21/7/075023, The pizzicato knee-joint energy harvester: characterization with biomechanical data and the effect of backpack load. The abstract reads:
"Abstract References

Paper

The reduced power requirements of miniaturized electronics offer the opportunity to create devices which rely on energy harvesters for their power supply. In the case of wearable devices, human-based piezoelectric energy harvesting is particularly difficult due to the mismatch between the low frequency of human activities and the high-frequency requirements of piezoelectric transducers. We propose a piezoelectric energy harvester, to be worn on the knee-joint, that relies on the plucking technique to achieve frequency up-conversion. During a plucking action, a piezoelectric bimorph is deflected by a plectrum; when released due to loss of contact, the bimorph is free to vibrate at its resonant frequency, generating electrical energy with the highest efficiency. A prototype, featuring four PZT-5H bimorphs, was built and is here studied in a knee simulator which reproduces the gait of a human subject. Biomechanical data were collected with a marker-based motion capture system while the subject was carrying a selection of backpack loads. The paper focuses on the energy generation of the harvester and how this is affected by the backpack load. By altering the gait, the backpack load has a measurable effect on performance: at the highest load of 24 kg, a minor reduction in energy generation (7%) was observed and the output power is reduced by 10%. Both are so moderate to be practically unimportant. The average power output of the prototype is 2.06 ± 0.3 mW, which can increase significantly with further optimization."
Crossposted at GadgetPundit.