Wireless sensors are much more practical when energy harvesters are used to eliminate the need for power wiring. Energy harvesters convert vibration, heat or light into electrical energy which is used to power a rechargeable battery or a capacitor.
When designing a wireless sensing system with an energy harvester, multiple components must be optimized. The sensor and the radio must consume minimal amounts of power when active, and use little or no power when not actively sensing and exchanging data.