Water Flow Monitoring System The sensor module consists of four ultrasonic sensors. Each sensor sends out an ultrasonic signal at different frequencies. When the ultrasonic wave hits the surface of the water, the reflected waves are received by the sensor. The frequency of the reflected wave is proportional to the distance between the sensor and the surface of the water. This means that the higher the frequency, the closer the sensor is to the surface of the water and vice versa. The sensor module uses an Arduino Uno microcontroller board to receive the signals from the ultrasonic sensors. The Arduino Uno board processes the signals and converts them into digital values. These values are then sent to the gateway module through BLE protocol.

• LoRa 4G Modbus gateway has built-in LoRa module and 4G module, and integrates Modbus RTU protocol, specially used for industrial communication.