Using stm32 for wifi remote temperature control fan system

Designing a WiFi remote temperature control fan system using an STM32 microcontroller involves integrating temperature sensing, fan control, and WiFi connectivity for remote monitoring and control. Below is a step-by-step guide to implementing this system: System Overview Temperature Sensing: Use a temperature sensor (e.g., DHT22, LM35, or DS18B20) to measure ambient temperature. Fan Control: Use a PWM signal to control the speed of a DC fan based on the temperature. WiFi Connectivity: Use a WiFi module (e.g., ESP8266 or ESP32) to enable remote control and monitoring. User Interface: Provide a mobile app or web interface for remote control. Hardware Components STM32 Microcontroller: STM32F4 or STM32F1 series (e.g., STM32F407 or STM32F103). Temperature Sensor: DHT22 (digital) or LM35 (analog). WiFi Module: ESP8266 (e.g., ESP-01) or ESP32. DC Fan: A small DC fan with PWM speed control. Power Supply: 5V or 3.3V power supply for the STM32 and peripherals. Transistor/MOSFET: To control the fan using PWM (e.g., 2N2222 transistor or IRF540 MOSFET). Resistors and Capacitors: For circuit stability and signal conditioning. System Block Diagram +-------------------+ +-------------------+ +----------------+ | Temperature Sensor| | STM32 Microcontrol| | WiFi Module | | (e.g., DHT22) | | ler (e.g., STM32F4| | (e.g., ESP8266)| +--------+----------+ +--------+----------+ +--------+-------+ | | | | | | v v v +--------+-------------------------------------------------------+-------+ | | | Fan Control Circuit | | (PWM Signal to Fan) | | | +--------+-------------------------------------------------------+-------+ | | | | | | v v v +--------+----------+ +-------------------+ +----------------+ | DC Fan | | Power Supply | |Remote Interface| | | | (5V/3.3V) | |(Mobile App/Web)| +-------------------+ +-------------------+ +----------------+ Software Design Temperature Sensing: Read temperature data from the sensor. Example for DHT22: c float temperature = DHT22_ReadTemperature(); Fan Control: Use PWM to control the fan speed based on temperature. Example: c if (temperature > 30) { PWM_SetDutyCycle(100); // Full speed } else if (temperature > 25) { PWM_SetDutyCycle(75); // 75% speed } else { PWM_SetDutyCycle(0); // Fan off } WiFi Communication: Use AT commands or a library (e.g., ESP8266 AT commands) to communicate with the WiFi module. Example for ESP8266: c ESP8266_SendCommand("AT+CIPSEND=0,10"); // Send data ESP8266_SendData("Temperature: 25.5"); Remote Control: Implement a simple TCP/IP server on the STM32 to receive commands from the remote interface. Example: c char command[10]; ESP8266_ReceiveData(command); if (strcmp(command, "FAN_ON") == 0) { PWM_SetDutyCycle(100); // Turn fan on } else if (strcmp(command, "FAN_OFF") == 0) { PWM_SetDutyCycle(0); // Turn fan off } User Interface: Develop a mobile app or web interface to send commands and display temperature data. Example: Use a simple web server on the ESP8266 or a cloud platform (e.g., Blynk, ThingSpeak). Implementation Steps Hardware Setup: Connect the temperature sensor to the STM32 (e.g., GPIO for DHT22, ADC for LM35). Connect the fan control circuit (PWM output to transistor/MOSFET). Connect the WiFi module to the STM32 via UART. STM32 Configuration: Configure GPIO for sensor and fan control. Configure UART for communication with the WiFi module. Configure PWM for fan speed control. Software Development: Write code to read temperature data and control the fan. Implement WiFi communication for remote control and monitoring. Test the system with a mobile app or web interface. Testing and Debugging: Verify temperature readings and fan control. Test WiFi connectivity and remote control functionality. Optimize the system for performance and reliability. Example Code c #include "stm32f4xx.h" #include "dht22.h" #include "pwm.h" #include "esp8266.h" float temperature; char command[10]; int main(void) { // Initialize peripherals DHT22_Init(); PWM_Init(); ESP8266_Init(); while (1) { // Read temperature temperature = DHT22_ReadTemperature(); // Control fan

+-------------------+       +-------------------+       +----------------+
| Temperature Sensor|       | STM32 Microcontrol|       | WiFi Module    |
| (e.g., DHT22)     |       | ler (e.g., STM32F4|       | (e.g., ESP8266)|
+--------+----------+       +--------+----------+       +--------+-------+
         |                           |                           |
         |                           |                           |
         v                           v                           v
+--------+-------------------------------------------------------+-------+
|                                                                        |
|                          Fan Control Circuit                           |
|                          (PWM Signal to Fan)                           |
|                                                                        |
+--------+-------------------------------------------------------+-------+
         |                           |                           |
         |                           |                           |
         v                           v                           v
+--------+----------+       +-------------------+       +----------------+
| DC Fan            |       | Power Supply      |       |Remote Interface|
|                   |       | (5V/3.3V)         |       |(Mobile App/Web)|
+-------------------+       +-------------------+       +----------------+

c

float temperature = DHT22_ReadTemperature();

c

if (temperature > 30) {
    PWM_SetDutyCycle(100); // Full speed
} else if (temperature > 25) {
    PWM_SetDutyCycle(75);  // 75% speed
} else {
    PWM_SetDutyCycle(0);   // Fan off
}

c

ESP8266_SendCommand("AT+CIPSEND=0,10"); // Send data
ESP8266_SendData("Temperature: 25.5");

c

char command[10];
ESP8266_ReceiveData(command);
if (strcmp(command, "FAN_ON") == 0) {
    PWM_SetDutyCycle(100); // Turn fan on
} else if (strcmp(command, "FAN_OFF") == 0) {
    PWM_SetDutyCycle(0);   // Turn fan off
}

c

#include "stm32f4xx.h"
#include "dht22.h"
#include "pwm.h"
#include "esp8266.h"

float temperature;
char command[10];

int main(void) {
    // Initialize peripherals
    DHT22_Init();
    PWM_Init();
    ESP8266_Init();

    while (1) {
        // Read temperature
        temperature = DHT22_ReadTemperature();

        // Control fan based on temperature
        if (temperature > 30) {
            PWM_SetDutyCycle(100); // Full speed
        } else if (temperature > 25) {
            PWM_SetDutyCycle(75);  // 75% speed
        } else {
            PWM_SetDutyCycle(0);   // Fan off
        }

        // Send temperature data to remote interface
        char buffer[20];
        sprintf(buffer, "Temperature: %.1f", temperature);
        ESP8266_SendData(buffer);

        // Check for remote commands
        if (ESP8266_ReceiveData(command)) {
            if (strcmp(command, "FAN_ON") == 0) {
                PWM_SetDutyCycle(100); // Turn fan on
            } else if (strcmp(command, "FAN_OFF") == 0) {
                PWM_SetDutyCycle(0);   // Turn fan off
            }
        }

        // Delay for stability
        Delay_ms(1000);
    }
}

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