The smallest changes in temperature, vibration, pressure, light or motion all produce energy that can be harvested and used to send a signal.
The principle of energy harvesting is not new (self winding watches have a history dating back hundreds of years), even the concept of using energy from the immediate environment to power wireless sensors has been done before (using outdoor solar panels on a sunny day). EnOcean’s radical breakthrough is to reduce the energy required to send a signal to an incredibly small amount. This change in energy requirements means that EnOcean sensors operate where other technologies cannot. A simple example is when our sensors are solar powered they can operate indoors, in a low light environment.
EnOcean just raised $13 million.