The kinetic energy harvesting of body movement seems great but I have one caveat with the idea: it assumes everybody can generate that type of body movement. Right as the pandemic began I received my certification as an assistive technology specialist so I am now trained to view technology in terms of how it can be used to assist disabled individuals. There are people who are paralyzed or in wheelchairs who can't walk around to generate that level of small amounts of energy for wearable sensors. For those individuals that is still going to have to come from batteries or be harvested through another method such as thermal body heat.
RE: Have Electricity, Will Travel