WSLRW-ULB is a LoRaWAN ultrasonic level sensor to measure solid surface level in trash bin for waste management systems ... This level sensor uses ultrasonic technology to measure the solid surface of waste, the principle is to measure the time of flight of the ultrasound pulse in the air environment. The ultrasound pulse will be ejected from ultrasonic transducer, go thru the air and reach the solid surface of the waste, then reflected back to the ultrasonic transducer, the measuring circuit will measure the flight time of the pulse then calculated distance from the transducer to the surface. The ultra-low power design and smart firmware allow the sensor to last for up to 10 years with just 2 x AA batteries (depending on configuration). The sensor will transmit data over kilo-meters away to the LoRaWAN gateway, any brand on the market.