Energy Harvesters To The Rescue Of Dismounted Soldiers By Reducing Battery Burden

Who said Energy can only be harvested from huge setups made of complex circuitry. If we look around us, we can realize that energy can be harvested from each and every aspect of nature. The best example is a photocell. There is yet another simple component that can help you harvest energy from the surrounding forces. I am talking about the piezoelectric crystal. We know that lateral pressure applied to the crystal will be converted into electrical energy. Researchers from Cranfield, Liverpool and Salford universities have used this idea effectively in a body-worn energy harvester.



The device is strapped to the outside of the knee and uses the crystal to generate energy from the user’s walking movements. The device can harvest around 2mW of power and that is enough to supply body monitoring devices such as heart rate monitors, pedometers and accelerometers with energy, thus eliminating the need to replace the batteries very frequently. 2mW may seem to be a very insignificant amount of energy but the scientists are confident of ability to harvest up to 30mW by incorporating some developments in the device. If that is made possible, then it can be used to support new-generation GPS devices, more frequent and longer wireless transmission.

It is a circular device with a hub and an outer ring. It rotates as the user walks. The plectrum plucks the four energy generating arms (bimorphs) that are attached to the inner hub causing it to vibrate. This process will cause the generation of electricity. The bimorph (Piezoelectric crystal) can convert mechanical energy to electrical energy and vice versa.

There is a strong reason why knee should be selected. There are more parts in our body but it is the knee that experiences a large change in its angle (when walking, generally at significant speeds). Due to this reason, the device can generate more energy when connected to the knee.

This research, which was published in the Institute of Physics’ Smart Materials and Structures journal, was initially funded by the EPSRC and the government’s Defense Science and Technology Laboratory (DSTL) has been built with a main motive to reduce the heavy battery burden on dismounted soldiers.

SOURCE: The Engineer - Home