Design of thermostatic shower control circuit based on 51 microcontroller

Abstract:
This article proposes a design scheme for an intelligent thermostatic shower control system based on the 51 series microcontroller. The system uses a temperature sensor to monitor the water temperature in real time, and accurately controls the working status of the electric heating element through a PID algorithm, thereby achieving precise control of the outlet water temperature. At the same time, the system also has a human-computer interaction interface to facilitate users to set and check the working status of the shower.

Keywords: 51 microcontroller; constant temperature shower; temperature control; PID algorithm; human-computer interaction

1. Introduction
(describe the background, including existing problems with existing showers and the development trends and application prospects of intelligent thermostat technology)

2. Overall system design plan
1. System composition and working principle: Description The system is mainly composed of 51 microcontroller, temperature sensor, relay drive module, electric heating element, display and button module, etc.
2. Temperature detection module design: Detailed introduction to the type of temperature sensor used and its interface connection method with the microcontroller.
3. Temperature control strategy: Introduce how to use the PID algorithm to achieve constant temperature control, including the PID parameter tuning method and the specific implementation of the algorithm.
4. Human-computer interaction module design: Explain how to use the LCD display or LED digital tube to display the current water temperature and set temperature, and set the temperature through buttons.

3. Hardware design and implementation
1. Microcontroller minimum system design
2. Temperature sensor interface circuit design
3. Relay drive circuit design to control the on-off of electric heating elements
4. Display and button module circuit design

4. Software design and implementation
1. System main program flow chart
2. C language programming implementation of PID algorithm
3. Temperature sampling, processing and control program design
4. Program design of human-computer interaction interface

5. Experimental testing and result analysis
(show physical photos of the actually built system, give experimental data, and analyze the stability and accuracy of the system)

6. Conclusion
(summarize the design results, point out possible improvements and future research directions)

references

The above is a general paper outline for designing a thermostatic shower control circuit based on the 51 microcontroller. The specific content needs to be filled in and improved based on the actual project implementation. During the writing process, the feasibility, practicality, economy, and safety of the system design should be fully considered.

Part of the code is as follows

#include <reg52.h> // 导入51单片机头文件

// 假设已定义相关硬件端口和宏定义
#define TEMP_SENSOR_PIN P1_0 // 温度传感器连接的ADC输入引脚
#define RELAY_PIN P2_0 // 继电器驱动输出引脚
#define SETPOINT_TEMP 40 // 用户设定的目标温度

// PID参数（示例）
#define KP 5.0
#define KI 0.2
#define KD 1.5
volatile float integral = 0; // 积分项
float prev_error = 0; // 上一时刻误差

void ADC_Init(void); // 初始化ADC模块
unsigned int ReadTemperature(void); // 读取温度传感器值并转换为温度
void PID_Control(void); // PID控制函数
void RelayControl(float dutyCycle); // 继电器控制函数，接收占空比信号

int main(void) {
    ADC_Init(); // 初始化ADC
    while (1) {
        // 读取当前水温
        unsigned int currentTemp = ReadTemperature();
        float currentTempFloat = (float)currentTemp / 100; // 假设转换为摄氏度

        // 计算误差
        float error = SETPOINT_TEMP - currentTempFloat;

        // 执行PID计算
        PID_Control(error);

        // 根据PID输出结果控制继电器
        RelayControl(PID_Output);

        // 延时，等待下一个采样周期
        Delay_ms(1000); // 假设每秒采样一次
    }
}

void PID_Control(float error) {
    // 这里是PID算法的具体实现，包括比例、积分、微分项计算
    float proportional = KP * error;
    integral += KI * error * dt; // dt为采样周期
    float derivative = (error - prev_error) / dt;
    
    float PID_Output = proportional + integral + derivative;

    // 对PID输出做饱和处理以防过量驱动继电器
    if (PID_Output > MAX_DUTYCYCLE) PID_Output = MAX_DUTYCYCLE;
    if (PID_Output < MIN_DUTYCYCLE) PID_Output = MIN_DUTYCYCLE;

    prev_error = error;
    return PID_Output;
}

void RelayControl(float dutyCycle) {
    // 根据dutyCycle控制PWM信号，进而控制继电器开关时间以调整加热功率
    // 具体实现取决于你使用的PWM方式和单片机型号
}

Design of thermostatic shower control circuit based on 51 microcontroller

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