ESP32 WiFi Configuration

Course 5：TEMP_Fan ================== .. image:: _static/COURSE/14.temp.png :align: center ---- Learning Objectives ------------------- - Learn the working principle and data communication method of the DHT11 temperature and humidity sensor; - Master the method of reading temperature and humidity data using ESP32; - Understand the application of single-bus communication protocol in sensor data acquisition. ---- Required Component ------------------ - Motor Fan Module、DHT11 Senor ---- Working Principle ----------------- - The DHT11 is a single-bus digital temperature and humidity sensor that integrates a temperature sensing element, a resistive humidity sensing element, and a signal processing chip. - It transmits a 40-bit digital signal sequentially via a single bus, sending the acquired temperature and humidity data to the main controller in pulse-width encoded format to achieve environmental temperature and humidity detection. - The 40-bit data（5 bytes in total）consists of: an integer part of humidity, a decimal part of humidity, an integer part of temperature, a decimal part of temperature, and a checksum (the lower 8 bits of the sum of the first four bytes). ---- Wiring -------- - Motor Fan Module —— ESP32 IO27 - DHT11 Senor —— ESP32 IO15 .. image:: _static/COURSE/15.TEMP1.png :align: center ---- Example Code ------------ .. code-block:: cpp #include #include #include #include // ========== Pin Definitions ========== #define DHTPIN 15 #define DHTTYPE DHT11 #define FAN_PIN 27 DHT dht(DHTPIN, DHTTYPE); WebServer server(80); // ========== Variables ========== float temperature = 0.0; float humidity = 0.0; float thresholdTemp = 30.0; // Default threshold bool autoMode = true; bool fanState = false; // ========== WiFi Configuration ========== const char* apSSID = "TEMP_Fan"; // Access Point SSID (no password) const char* apPassword = NULL; // No password String wifiSSID = ""; // Store target WiFi SSID String wifiPassword = ""; // Store target WiFi password bool isConfigMode = true; // Configuration mode flag bool wifiConnected = false; // WiFi connection status // ========== Preferences for storing WiFi credentials ========== Preferences preferences; // ========== Read Sensor ========== void readDHT() { temperature = dht.readTemperature(); humidity = dht.readHumidity(); } // ========== HTML Configuration Page ========== String configHTMLPage() { String page = R"rawliteral( ESP32 WiFi Configuration

WiFi Configuration

)rawliteral"; return page; } // ========== HTML Control Page (Original Design) ========== String controlHTMLPage() { String page = R"rawliteral( ESP32 Human Body Detection System

ESP32 Temperature Fan System

Temperature: 0°C

Humidity: 0%

Mode

Auto

Manual Fan Control

Temperature Threshold

)rawliteral"; return page; } // ========== Request Handlers ========== void handleRoot() { if (isConfigMode) { server.send(200, "text/html", configHTMLPage()); } else { server.send(200, "text/html", controlHTMLPage()); } } void handleData() { readDHT(); if (autoMode) { if (temperature >= thresholdTemp) fanState = true; else fanState = false; digitalWrite(FAN_PIN, fanState ? HIGH : LOW); } String json = "{"; json += "\"temperature\":" + String(temperature,1) + ","; json += "\"humidity\":" + String(humidity,0) + ","; json += "\"autoMode\":" + String(autoMode ? "true" : "false") + ","; json += "\"fanState\":" + String(fanState ? "true" : "false"); json += "}"; server.send(200, "application/json", json); } void handleToggleMode() { autoMode = !autoMode; Serial.println(autoMode ? "Mode: Auto" : "Mode: Manual"); server.send(200, "text/plain", "ok"); } void handleToggleFan() { if (!autoMode) { fanState = !fanState; digitalWrite(FAN_PIN, fanState ? HIGH : LOW); Serial.println(fanState ? "Fan ON (Manual)" : "Fan OFF (Manual)"); } server.send(200, "text/plain", "ok"); } void handleSetThreshold() { if (server.hasArg("val")) thresholdTemp = server.arg("val").toFloat(); Serial.println("Threshold set to: " + String(thresholdTemp,1) + "°C"); server.send(200, "text/plain", "ok"); } void handleConfigure() { wifiSSID = server.arg("ssid"); wifiPassword = server.arg("password"); // Save credentials to preferences preferences.putString("ssid", wifiSSID); preferences.putString("password", wifiPassword); server.send(200, "text/html", "

Connecting to WiFi...

" "

SSID: " + wifiSSID + "

" "

Device will restart and attempt connection.

" "" ""); delay(2000); ESP.restart(); } // ========== Connect to WiFi ========== bool connectToWiFi() { if (wifiSSID == "") return false; Serial.println("Attempting to connect to WiFi: " + wifiSSID); WiFi.begin(wifiSSID.c_str(), wifiPassword.c_str()); int attempts = 0; while (WiFi.status() != WL_CONNECTED && attempts < 20) { delay(500); Serial.print("."); attempts++; } if (WiFi.status() == WL_CONNECTED) { Serial.println("\nWiFi connected successfully!"); Serial.println("IP address: " + WiFi.localIP().toString()); return true; } else { Serial.println("\nFailed to connect to WiFi"); return false; } } // ========== Setup Access Point ========== void setupAccessPoint() { Serial.println("Setting up Access Point..."); WiFi.softAP(apSSID, apPassword); Serial.println("Access Point started"); Serial.println("SSID: " + String(apSSID)); Serial.println("Password: None (Open Network)"); Serial.println("IP address: " + WiFi.softAPIP().toString()); } // ========== Setup ========== void setup() { Serial.begin(115200); pinMode(FAN_PIN, OUTPUT); dht.begin(); // Initialize preferences preferences.begin("wifi-config", false); // Try to load saved WiFi credentials wifiSSID = preferences.getString("ssid", ""); wifiPassword = preferences.getString("password", ""); Serial.println("=== ESP32 Temperature Fan System ==="); if (wifiSSID != "" && connectToWiFi()) { // Successfully connected to WiFi isConfigMode = false; wifiConnected = true; Serial.println("Mode: Station (Connected to WiFi)"); } else { // Enter configuration mode (Access Point) isConfigMode = true; wifiConnected = false; setupAccessPoint(); Serial.println("Mode: Access Point (Configuration)"); } server.on("/", handleRoot); server.on("/data", handleData); server.on("/toggleMode", handleToggleMode); server.on("/toggleFan", handleToggleFan); server.on("/setThreshold", handleSetThreshold); server.on("/configure", HTTP_POST, handleConfigure); server.begin(); Serial.println("Web server started"); } void loop() { server.handleClient(); } ---- **Code burning options** 1. You can directly copy the code provided above into the Arduino IDE for burning. 2. Find the **5.TEMP_Fan.ino** file in the provided folder, download it, open it with the **Arduino IDE**, and burn the program to the ESP32 development board. 3. Find the **5.TEMP_Fan.bin** file in the provided folder, download it and use **Flash Download Tool** to flash the program to the ESP32 development board. ---- Effects Demonstration --------------------- 1. The webpage displays temperature and humidity values. 2. The system supports switching between manual and automatic modes. In manual mode, the fan can be manually turned on and off via a web button. In automatic mode, the system will automatically turn on the fan to cool down when the ambient temperature reaches a preset threshold, and will automatically turn off when the temperature drops below the threshold. 3. New temperature thresholds can be set via the webpage. .. image:: _static/COURSE/16.TEMP.png :width: 800 :align: center ----