Scientists from U.K.’s Cranfield University, University of Liverpool and University of Salford were able to develop a wearable device that generates electricity from knee movements. Called the pizzicato knee-joint energy harvester, the device reportedly has the capability to convert knee movement into electricity which can be used to power other gadgets such as heart rate monitors, accelerometers, and pedometers. The knee-joint energy harvester can be worn on the knee-joint. Dr. Michele Pozzi of Cranfield University explained that the device relies on a plucking technique to achieve frequency 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,” Dr. Pozi explained. Data is reportedly collected with a marker-based motion capture system while the subject was carrying a selection of backpack loads.
The scientists are hoping that their energy harvester could one day be of use to soldiers who are carrying heavy electronic devices and batteries on military missions. Scientists said that the device is still able to harvest two milliwatts of power, but pointed out that improving its performance to 30 milliwatts, the reputed power of a GPS tracking system, is highly attainable. You can check out Dr. Pozi’s paper here.