EnOcean Alliance offers an alternative to battery-powered sensors. Self-powered switches and sensors are miniature energy harvesters, collecting the energy created by slight changes in pressure, temperature, light and motion. This low-maintenance technology is being widely used in building automation. For example, the WaterSensor eco utilizes fiber disks which expand in the presence of water; the energy generated is used to send a message to the WaterControl 01 or Afriso gateway.