Course 6：Human_Count ===================== .. image:: _static/COURSE/17.human.png :align: center ---- Learning Objectives ------------------- - Understand the detection principle of PIR infrared human body sensors - Master the digital input detection and interrupt handling mechanism of ESP32 - Learn to use a web server to build a local web interface for real-time data viewing and control ---- Required Component ------------------ - Active Buzzer、PIR Senor ---- Working Principle ----------------- - An active buzzer internally consists of an oscillation circuit and a piezoelectric ceramic element. When a DC voltage is supplied externally, the internal oscillation circuit automatically generates an audio signal to drive the piezoelectric element to vibrate, thus producing sound. - A PIR（Passive Infrared Sensor） operates using the pyroelectric effect.When an object with a different temperature （such as a human body） enters its detection area, the infrared radiation emitted by the human body（wavelength approximately 10 μm）causes a change in the charge on the sensor surface, thereby generating a weak electrical signal. ---- Wiring -------- - Active Buzzer —— ESP32 IO25 - PIR Senor —— ESP32 IO33 .. image:: _static/COURSE/18.human.png :align: center ---- Example Code ------------ .. code-block:: cpp #include #include #include // ======== Pin Definitions ======== #define PIR_PIN 33 #define BUZZER_PIN 25 WebServer server(80); volatile bool motionDetected = false; unsigned long lastMotionTime = 0; int peopleCount = 0; bool alarmEnabled = true; // ======== WiFi Configuration ======== const char* apSSID = "Human_Count"; // 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; // ======== HTML Configuration Page ======== String configHTMLPage() { String html = R"rawliteral( ESP32 WiFi Configuration

WiFi Configuration

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

ESP32 Human Body Detection System

Detected Count:

)rawliteral"; return html; } // ======== Request Handlers ======== void handleRoot() { if (isConfigMode) { server.send(200, "text/html", configHTMLPage()); } else { server.send(200, "text/html", controlHTMLPage()); } } void handleStatus() { String motion = motionDetected ? "⚠️ Motion Detected!" : "✅ No Motion"; String json = "{\"motion\":\"" + motion + "\",\"count\":" + String(peopleCount) + "}"; server.send(200, "application/json", json); } void handleReset() { peopleCount = 0; Serial.println("[Web] Counter Reset"); 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(PIR_PIN, INPUT); pinMode(BUZZER_PIN, OUTPUT); digitalWrite(BUZZER_PIN, LOW); // Initialize preferences preferences.begin("wifi-config", false); // Try to load saved WiFi credentials wifiSSID = preferences.getString("ssid", ""); wifiPassword = preferences.getString("password", ""); Serial.println("=== ESP32 Human Body Detection 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("/status", handleStatus); server.on("/reset", handleReset); server.on("/configure", HTTP_POST, handleConfigure); server.begin(); Serial.println("Web server started"); } // ======== Main Loop ======== void loop() { server.handleClient(); int pirState = digitalRead(PIR_PIN); if (pirState == HIGH && !motionDetected) { motionDetected = true; peopleCount++; Serial.println("[Sensor] Motion detected!"); if (alarmEnabled) { digitalWrite(BUZZER_PIN, HIGH); delay(1000); digitalWrite(BUZZER_PIN, LOW); } lastMotionTime = millis(); } if (pirState == LOW && millis() - lastMotionTime > 2000) { motionDetected = false; } } ---- **Code burning options** 1. You can directly copy the code provided above into the Arduino IDE for burning. 2. Find the **6.Human_Count.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 **6.Human_Count.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 PIR sensor is used to detect human activity. A buzzer sounds when someone is detected passing by. 2. The web interface includes a people counter, displaying the total number of detected people in real time and providing a "Reset Counter" button to reset the count. .. image:: _static/COURSE/19.human.png :width: 800 :align: center ----