"基于单片机的太阳能智能热水器水位控制仪设计"

The graduation design project titled "Intelligent Water Level Control Device for Solar Water Heater Based on Single-chip Microcomputer" focuses on the development of a smart control system for solar water heaters. The system is centered around the 89C52 single-chip microcontroller and is equipped with a resistive 4-level water level sensor, a negative temperature coefficient (NTC) thermistor temperature sensor, an 8255A extension keyboard and display device, and drive circuits for electromagnetic valves, electric heating, and alarms. The system is capable of measuring and displaying water level and temperature inside the solar water heater, displaying time, automatically refilling water when water is insufficient, generating water overflow alarms, manually refilling water and setting parameters, and intelligently heating water when the temperature is too low. The first chapter of the document provides an overview of the research status of intelligent control systems for solar water heaters and outlines the main tasks of the project. The second chapter introduces the overall structure of the system, while the third chapter focuses on the water level and temperature measurement circuits. The fourth chapter discusses the clock circuit, the fifth chapter covers the display and keyboard circuit, and the sixth chapter introduces other circuits used in the system. The seventh chapter describes the hardware debugging process of the water level measurement circuit. Unique to this system is the use of an RC charge-discharge method for processing the resistance data from the water level sensor and the temperature sensor. This approach simplifies the circuit design and reduces manufacturing costs compared to using an A/D converter. The system is particularly suitable for applications where precise water level and temperature measurements are not imperative. Keywords: solar energy, water heater, controller, 89C52, RC charge-discharge.