first commit

.gitignore

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+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

.vscode/extensions.json

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+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.16.0)
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(KgeuTraining)

include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the convention is to give header files names that end with `.h'.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into the executable file.
+
+The source code of each library should be placed in a separate directory
+("lib/your_library_name/[Code]").
+
+For example, see the structure of the following example libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional. for custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+Example contents of `src/main.c` using Foo and Bar:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+The PlatformIO Library Dependency Finder will find automatically dependent
+libraries by scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:wemos_d1_uno32]
+platform = espressif32
+board = wemos_d1_uno32
+framework = espidf
+monitor_speed = 115200
+monitor_filters = 
+    default
+    esp32_exception_decoder

src/CMakeLists.txt

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+# This file was automatically generated for projects
+# without default 'CMakeLists.txt' file.
+
+FILE(GLOB_RECURSE app_sources ${CMAKE_SOURCE_DIR}/src/*.*)
+
+idf_component_register(SRCS ${app_sources}
+                       REQUIRES nvs_flash)

src/main.c

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+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+#include "esp_system.h"
+#include "esp_wifi.h"
+#include "esp_event.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+#include "driver/gpio.h"
+#include "lwip/sockets.h"
+#include "lwip/dns.h"
+#include "lwip/netdb.h"
+
+static const char *TAG = "KgeuTraining";
+
+// WiFi AP Configuration
+#define WIFI_SSID      "KgeuTraining_AP"
+#define WIFI_PASS      "12345678"
+#define WIFI_CHANNEL   1
+#define MAX_STA_CONN   4
+
+// Hall Sensor GPIO pins (KY-003)
+#define HALL_SENSOR_TOP_PIN    GPIO_NUM_4
+#define HALL_SENSOR_BOTTOM_PIN GPIO_NUM_5
+
+// TCP server configuration
+#define TCP_PORT 8080
+#define MAX_CLIENTS 4
+#define TCP_BUFFER_SIZE 128
+
+// Position states
+typedef enum {
+    POSITION_TOP,
+    POSITION_BOTTOM,
+    POSITION_MIDDLE
+} position_state_t;
+
+static position_state_t current_position = POSITION_MIDDLE;
+static position_state_t last_position = POSITION_MIDDLE;
+
+// TCP client list
+static int tcp_clients[MAX_CLIENTS] = {-1, -1, -1, -1};
+static int tcp_client_count = 0;
+static int tcp_server_socket = -1;
+
+// Mutex for client list access
+static SemaphoreHandle_t client_mutex = NULL;
+
+// Forward declaration
+static void send_position_to_client(int sock_fd, const char *position);
+
+/**
+ * Add TCP client to the list
+ */
+static void add_tcp_client(int sock_fd) {
+    xSemaphoreTake(client_mutex, portMAX_DELAY);
+    for (int i = 0; i < MAX_CLIENTS; i++) {
+        if (tcp_clients[i] == -1) {
+            tcp_clients[i] = sock_fd;
+            tcp_client_count++;
+            ESP_LOGI(TAG, "TCP client connected, total: %d", tcp_client_count);
+            
+            // Send current position immediately
+            const char *current_pos_str;
+            switch (current_position) {
+                case POSITION_TOP:
+                    current_pos_str = "top";
+                    break;
+                case POSITION_BOTTOM:
+                    current_pos_str = "bottom";
+                    break;
+                case POSITION_MIDDLE:
+                    current_pos_str = "middle";
+                    break;
+                default:
+                    current_pos_str = "middle";
+                    break;
+            }
+            send_position_to_client(sock_fd, current_pos_str);
+            
+            xSemaphoreGive(client_mutex);
+            return;
+        }
+    }
+    ESP_LOGW(TAG, "Maximum clients reached");
+    xSemaphoreGive(client_mutex);
+}
+
+/**
+ * Remove TCP client from the list
+ */
+static void remove_tcp_client(int sock_fd) {
+    xSemaphoreTake(client_mutex, portMAX_DELAY);
+    for (int i = 0; i < MAX_CLIENTS; i++) {
+        if (tcp_clients[i] == sock_fd) {
+            tcp_clients[i] = -1;
+            tcp_client_count--;
+            ESP_LOGI(TAG, "TCP client disconnected, total: %d", tcp_client_count);
+            xSemaphoreGive(client_mutex);
+            return;
+        }
+    }
+    xSemaphoreGive(client_mutex);
+}
+
+/**
+ * Send position to a specific TCP client
+ */
+static void send_position_to_client(int sock_fd, const char *position) {
+    // Simple JSON formatting: {"position": "top"}
+    char json_string[64];
+    snprintf(json_string, sizeof(json_string), "{\"position\":\"%s\"}\n", position);
+    
+    ESP_LOGI(TAG, "Sending to client %d: %s", sock_fd, json_string);
+    
+    int len = strlen(json_string);
+    int sent = send(sock_fd, json_string, len, 0);
+    
+    if (sent < 0) {
+        ESP_LOGE(TAG, "Error occurred during sending: errno %d", errno);
+        remove_tcp_client(sock_fd);
+        close(sock_fd);
+    } else if (sent != len) {
+        ESP_LOGW(TAG, "Sent %d bytes instead of %d", sent, len);
+    }
+}
+
+/**
+ * Broadcast JSON message to all connected TCP clients
+ */
+static void broadcast_position(const char *position) {
+    if (tcp_client_count == 0) {
+        return;  // No clients connected
+    }
+    
+    // Simple JSON formatting: {"position": "top"}
+    char json_string[64];
+    snprintf(json_string, sizeof(json_string), "{\"position\":\"%s\"}\n", position);
+    
+    ESP_LOGI(TAG, "Broadcasting: %s", json_string);
+    
+    xSemaphoreTake(client_mutex, portMAX_DELAY);
+    for (int i = 0; i < MAX_CLIENTS; i++) {
+        if (tcp_clients[i] != -1) {
+            int sock_fd = tcp_clients[i];
+            int len = strlen(json_string);
+            int sent = send(sock_fd, json_string, len, 0);
+            
+            if (sent < 0) {
+                ESP_LOGE(TAG, "Error sending to client %d: errno %d", sock_fd, errno);
+                remove_tcp_client(sock_fd);
+                close(sock_fd);
+            } else if (sent != len) {
+                ESP_LOGW(TAG, "Sent %d bytes instead of %d to client %d", sent, len, sock_fd);
+            }
+        }
+    }
+    xSemaphoreGive(client_mutex);
+}
+
+/**
+ * Handle individual TCP client connection
+ */
+static void tcp_client_task(void *pvParameters) {
+    int sock_fd = (int)(intptr_t)pvParameters;
+    char rx_buffer[TCP_BUFFER_SIZE];
+    
+    ESP_LOGI(TAG, "New client task started for socket %d", sock_fd);
+    
+    // Set socket timeout
+    struct timeval timeout;
+    timeout.tv_sec = 10;
+    timeout.tv_usec = 0;
+    setsockopt(sock_fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
+    
+    while (1) {
+        int len = recv(sock_fd, rx_buffer, sizeof(rx_buffer) - 1, 0);
+        
+        if (len < 0) {
+            if (errno == EAGAIN || errno == EWOULDBLOCK) {
+                // Timeout - continue
+                continue;
+            }
+            ESP_LOGI(TAG, "recv failed: errno %d", errno);
+            break;
+        } else if (len == 0) {
+            ESP_LOGI(TAG, "Connection closed by client");
+            break;
+        }
+        
+        // Null-terminate the received data
+        rx_buffer[len] = '\0';
+        ESP_LOGI(TAG, "Received %d bytes: %s", len, rx_buffer);
+        
+        // Echo back or process the received data if needed
+        // For now, we just log it
+    }
+    
+    ESP_LOGI(TAG, "Closing client socket %d", sock_fd);
+    remove_tcp_client(sock_fd);
+    close(sock_fd);
+    vTaskDelete(NULL);
+}
+
+/**
+ * TCP server task - accepts new connections
+ */
+static void tcp_server_task(void *pvParameters) {
+    struct sockaddr_in server_addr;
+    struct sockaddr_in client_addr;
+    socklen_t client_addr_len = sizeof(client_addr);
+    
+    // Create socket
+    tcp_server_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    if (tcp_server_socket < 0) {
+        ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
+        vTaskDelete(NULL);
+        return;
+    }
+    
+    // Set socket options
+    int opt = 1;
+    setsockopt(tcp_server_socket, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    
+    // Bind socket
+    server_addr.sin_family = AF_INET;
+    server_addr.sin_addr.s_addr = INADDR_ANY;
+    server_addr.sin_port = htons(TCP_PORT);
+    
+    if (bind(tcp_server_socket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+        ESP_LOGE(TAG, "Socket unable to bind: errno %d", errno);
+        close(tcp_server_socket);
+        vTaskDelete(NULL);
+        return;
+    }
+    
+    // Listen for connections
+    if (listen(tcp_server_socket, MAX_CLIENTS) < 0) {
+        ESP_LOGE(TAG, "Error occurred during listen: errno %d", errno);
+        close(tcp_server_socket);
+        vTaskDelete(NULL);
+        return;
+    }
+    
+    ESP_LOGI(TAG, "TCP server started on port %d", TCP_PORT);
+    
+    while (1) {
+        // Accept new connection
+        int client_sock = accept(tcp_server_socket, (struct sockaddr *)&client_addr, &client_addr_len);
+        
+        if (client_sock < 0) {
+            ESP_LOGE(TAG, "Unable to accept connection: errno %d", errno);
+            continue;
+        }
+        
+        ESP_LOGI(TAG, "New client connected from %s", inet_ntoa(client_addr.sin_addr));
+        
+        // Add client to list
+        add_tcp_client(client_sock);
+        
+        // Create task for this client
+        xTaskCreate(tcp_client_task, "tcp_client", 4096, (void*)(intptr_t)client_sock, 5, NULL);
+    }
+    
+    close(tcp_server_socket);
+    vTaskDelete(NULL);
+}
+
+/**
+ * WiFi event handler
+ */
+static void wifi_event_handler(void* arg, esp_event_base_t event_base,
+                              int32_t event_id, void* event_data) {
+    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_AP_STACONNECTED) {
+        wifi_event_ap_staconnected_t* event = (wifi_event_ap_staconnected_t*) event_data;
+        ESP_LOGI(TAG, "Station joined, AID=%d", event->aid);
+    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_AP_STADISCONNECTED) {
+        wifi_event_ap_stadisconnected_t* event = (wifi_event_ap_stadisconnected_t*) event_data;
+        ESP_LOGI(TAG, "Station left, AID=%d", event->aid);
+    }
+}
+
+/**
+ * Initialize WiFi Access Point
+ */
+static void wifi_init_softap(void) {
+    ESP_ERROR_CHECK(esp_netif_init());
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+    esp_netif_create_default_wifi_ap();
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
+
+    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
+                                                        ESP_EVENT_ANY_ID,
+                                                        &wifi_event_handler,
+                                                        NULL,
+                                                        NULL));
+
+    wifi_config_t wifi_config = {
+        .ap = {
+            .ssid = WIFI_SSID,
+            .ssid_len = strlen(WIFI_SSID),
+            .channel = WIFI_CHANNEL,
+            .password = WIFI_PASS,
+            .max_connection = MAX_STA_CONN,
+            .authmode = WIFI_AUTH_WPA2_PSK
+        },
+    };
+    
+    if (strlen(WIFI_PASS) == 0) {
+        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
+    }
+
+    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
+    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_config));
+    ESP_ERROR_CHECK(esp_wifi_start());
+
+    ESP_LOGI(TAG, "WiFi AP initialized. SSID:%s password:%s channel:%d",
+             WIFI_SSID, WIFI_PASS, WIFI_CHANNEL);
+}
+
+/**
+ * Initialize GPIO for hall sensors
+ */
+static void init_hall_sensors(void) {
+    gpio_config_t io_conf = {
+        .intr_type = GPIO_INTR_DISABLE,
+        .mode = GPIO_MODE_INPUT,
+        .pin_bit_mask = (1ULL << HALL_SENSOR_TOP_PIN) | (1ULL << HALL_SENSOR_BOTTOM_PIN),
+        .pull_down_en = GPIO_PULLDOWN_DISABLE,
+        .pull_up_en = GPIO_PULLUP_ENABLE  // KY-003 has pull-up resistor, enable internal pull-up
+    };
+    gpio_config(&io_conf);
+    
+    ESP_LOGI(TAG, "Hall sensors initialized on GPIO %d (top) and %d (bottom)",
+             HALL_SENSOR_TOP_PIN, HALL_SENSOR_BOTTOM_PIN);
+}
+
+/**
+ * Read position from hall sensors
+ */
+static position_state_t read_position(void) {
+    int top_sensor = gpio_get_level(HALL_SENSOR_TOP_PIN);
+    int bottom_sensor = gpio_get_level(HALL_SENSOR_BOTTOM_PIN);
+    
+    // KY-003: LOW when magnet is near, HIGH when no magnet
+    // Top sensor LOW = weight at top
+    // Bottom sensor LOW = weight at bottom
+    // Both HIGH = weight in middle
+    
+    if (top_sensor == 0) {
+        return POSITION_TOP;
+    } else if (bottom_sensor == 0) {
+        return POSITION_BOTTOM;
+    } else {
+        return POSITION_MIDDLE;
+    }
+}
+
+/**
+ * Task to monitor position changes and broadcast updates
+ */
+static void position_monitor_task(void *pvParameters) {
+    ESP_LOGI(TAG, "Position monitoring task started");
+    
+    while (1) {
+        current_position = read_position();
+        
+        // Broadcast if position changed
+        if (current_position != last_position) {
+            const char *position_str;
+            switch (current_position) {
+                case POSITION_TOP:
+                    position_str = "top";
+                    break;
+                case POSITION_BOTTOM:
+                    position_str = "bottom";
+                    break;
+                case POSITION_MIDDLE:
+                    position_str = "middle";
+                    break;
+                default:
+                    position_str = "middle";
+                    break;
+            }
+            
+            broadcast_position(position_str);
+            last_position = current_position;
+        }
+        
+        // Check every 100ms
+        vTaskDelay(pdMS_TO_TICKS(100));
+    }
+}
+
+/**
+ * Main application entry point
+ */
+void app_main(void) {
+    // Initialize NVS
+    esp_err_t ret = nvs_flash_init();
+    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        ret = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(ret);
+    
+    // Initialize WiFi AP
+    wifi_init_softap();
+    
+    // Wait for WiFi to be ready
+    vTaskDelay(pdMS_TO_TICKS(1000));
+    
+    // Initialize hall sensors
+    init_hall_sensors();
+    
+    // Create mutex for client list
+    client_mutex = xSemaphoreCreateMutex();
+    if (client_mutex == NULL) {
+        ESP_LOGE(TAG, "Failed to create mutex");
+        return;
+    }
+    
+    // Start TCP server task
+    xTaskCreate(tcp_server_task, "tcp_server", 4096, NULL, 5, NULL);
+    
+    // Start position monitoring task
+    xTaskCreate(position_monitor_task, "position_monitor", 2048, NULL, 5, NULL);
+    
+    ESP_LOGI(TAG, "KgeuTraining application started");
+    ESP_LOGI(TAG, "Connect to TCP server at 192.168.4.1:%d", TCP_PORT);
+}

test/README

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+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html