The Dragino LDDS20 is a LoRaWAN Ultrasonic liquid level sensor for Internet of Things solution. It uses non contact method to measure the height of liquid in a container without opening the container, and send the value via LoRaWAN network to IoT Server. The LDDS20 sensor is installed directly below the container to detect the height of the liquid level. The non contact measurement makes the measurement safety, easier and possible for some strict situations.