Using a ESP8266 (Witty Cloud) and a HC-SR04 it gards the level. Homeseer uses this data to send warnings if the level is to high (during very heavy rainfall)
Temperature, pressure and humidity in Weyher in der Pfalz, Germany. Solar powered Wemos with BME280 connected to public Wifi "Freifunk Weyher"
Wemos D1 mini combined with BME280 sensor measuring temperature, relative humidity and air pressure. Location: Saxony, Germany