Energy Harvesting From Fingers Motions Using A Wearable System: An Experimental Analysis

An experimental analysis is presented in order to assess the best conditions for energy harvesting from the movement of the fingers using a glove-shape wearable system. Polyvinylidene Fluoride (PVDF) piezofilms were used as piezoelectric generators; they were mounted on the glove so they coincide with different interphalangeal joints on both sides of each finger of the right hand. Two scenarios have been carried out for five minutes each and the root-mean-square (rms) voltage of each piezofilm was measured. Scenario 1 consisted in the use of a computer mouse for browsing different web-sites on the internet; scenario 2 consisted in the use of a keyboard to write a text of 190 words. Scenario 2 produced the greater voltage because the number of keys depressed was higher in comparison with the number of clicks on the computer mouse. In the Scenario 1, the greater voltage was obtained from the piezofilm located on the thumb which is a finger not involved with the click action when using a computer mouse so, in this case, it is possible to harvester energy from three fingers instead of two, as have been reported in previous studies. From the results obtained in both scenarios, the best location to place the piezofilms to increase energy harvesting is the posterior side of each finger, specifically on the proximal interphalangeal and metacarpophalangeal joints. Placing the piezofilms on the fingertips did not produce an increase in the generated voltage.