Design and construction of a digital water level controller that automatically controls, monitors and ensures a continuous reserve of water in the storage tank.

Abstract

This project’s goal was to design and construct a digital water level controller that automatically controls, monitors and ensures a continuous reserve of water in the storage tank. System included a microcontroller (AT Mega 328p) and a circuit (HC-SR04 sensors, pump, solenoid valve, relays, 0.91-inch OLED display, DC power supply, perforated board, and wires) which worked together in monitoring and controlling the water level in a tank. Sound reflection (echo) was used to indicate water level in the main and reservoir tank i.e., ultrasonic sensor was installed on top of both tanks to send and receive sound waves – where time taken was converted to distance by microcontroller so as to give respective digital outputs that indicate water level in the tanks via OLED display. Desired water level inputs of the controller were 10cm and 28cm in main tank and reservoir tank respectively. When there is not enough water in the main tank (reading > 10cm from ultrasonic sensor) and yet there is enough water in the reservoir tank (reading < 28cm from ultrasonic sensor), the pump turns on to start operation. Otherwise, the pump goes off and solenoid valve opens provided main tank reading is still > 10cm from ultrasonic sensor. Both the pump and solenoid valve stopped supplying water to the main tank as long as it possessed enough water (main tank reading < 10cm from ultrasonic sensor). System stability was achieved utilizing PID values automatically tuned from MATLABTM. This was intended to sustainably manage water resources with minimum or no human involvement.

The main goal of the project was attained through meeting the specific objectives of; determining system design specifications, developing a conceptual design for the system, developing a detailed design of the system, constructing and evaluating a prototype for the system.

The project started with the study and research. With the information gathered from literature study and google forms, customer needs were filtered thus generating their designs concepts respectively. Most suitable and final design concepts were selected using a concept scoring matrix. Furthermore, a prototype to the final detailed design of the system was constructed to assess technical feasibility i.e., generation of CAD model using SolidWorksTM software, and electrical circuit design using EAGLETM software.