source code migrating from gitlab

001ESP32_Blink/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(blink)

001ESP32_Blink/README.md

@@ -0,0 +1,12 @@
+# Blink
+
+## The quintessential project
+The 'hello world' of embedded projects is to get an LED to blink
+
+## Links for more info:
+github for esp-idf: https://docs.espressif.com/projects/esp-idf/en/stable/esp32/index.html  
+
+docs: https://docs.espressif.com/  
+
+in depth video on esp-idf: https://www.youtube.com/watch?v=J8zc8mMNKtc  
+

001ESP32_Blink/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "blink.c"
+                    INCLUDE_DIRS ".")

001ESP32_Blink/main/blink.c

@@ -0,0 +1,25 @@
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+#include "driver/gpio.h"
+
+#define LED 2
+
+void app_main(void) {
+  const char *tag = "blink";
+  ESP_LOGI(tag, "Starting blink!\n");
+
+  const uint32_t hi = 1, lo = 0;
+  const TickType_t duration = 500 / portTICK_PERIOD_MS;
+
+  gpio_reset_pin(LED);
+  gpio_set_direction(LED, GPIO_MODE_OUTPUT);
+
+  while (1) {
+    gpio_set_level(LED, hi);
+    vTaskDelay(duration);
+    gpio_set_level(LED, lo);
+    vTaskDelay(duration);
+
+  }
+}

002LCD_1602/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(lcd-16x2)

002LCD_1602/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "lcd-16x2.c"
+                    INCLUDE_DIRS ".")

002LCD_1602/main/idf_component.yml

@@ -0,0 +1,17 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  panigrah/esp32-idf-hd44780: ^0.0.3

002LCD_1602/main/lcd-16x2.c

@@ -0,0 +1,44 @@
+#include "HD44780.h"
+#include <driver/i2c.h>
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <stdio.h>
+
+#define LCD_ADDR 0x27
+#define SDA_PIN 21
+#define SCL_PIN 22
+#define LCD_COLS 16
+#define LCD_ROWS 2
+
+void app_main(void) {
+  char *tag = "LCD_16x2";
+
+  ESP_LOGI(tag, "starting app_main");
+
+  LCD_init(LCD_ADDR, SDA_PIN, SCL_PIN, LCD_COLS, LCD_ROWS);
+
+  // LCD_clearScreen();
+  //  LCD_writeStr("Hello There");
+  //  LCD_setCursor(0, 1);
+  //  LCD_writeStr("  Second Row!      ");
+
+  char num[8];
+  while (true) {
+    LCD_clearScreen();
+    LCD_writeStr("Counting Down");
+
+    for (int i = 10; i >= 0; i--) {
+      LCD_setCursor(8, 1);
+      sprintf(num, "%d", i);
+      LCD_writeStr(num);
+      vTaskDelay(1000 / portTICK_PERIOD_MS);
+
+      LCD_setCursor(0, 1);
+      LCD_writeStr("                ");
+    }
+    LCD_clearScreen();
+    LCD_writeStr("Liftoff!");
+    vTaskDelay(2000 / portTICK_PERIOD_MS);
+  }
+}

003TempHumidity/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(temp-humidity)

003TempHumidity/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "temp-humidity.c"
+                    INCLUDE_DIRS ".")

003TempHumidity/main/idf_component.yml

@@ -0,0 +1,18 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  zorxx/dht: ^1.0.1
+  panigrah/esp32-idf-hd44780: ^0.0.3

003TempHumidity/main/temp-humidity.c

@@ -0,0 +1,57 @@
+#include "HD44780.h"
+#include "dht.h"
+#include <esp_err.h>
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#define DHT_PIN 25
+
+#define LCD_ADDR 0x27
+#define SDA_PIN 21
+#define SCL_PIN 22
+#define LCD_ROWS 16
+#define LCD_COLS 2
+
+float convertValue(int16_t val);
+float converTemp(int16_t celsius);
+
+void app_main(void) {
+
+  const char *tag = "TEMP_HUMID";
+  int16_t temp, humid;
+  char tempStr[32], humidStr[32];
+  ESP_LOGI(tag, "Starting our temp/humidity readings");
+  LCD_init(LCD_ADDR, SDA_PIN, SCL_PIN, LCD_COLS, LCD_ROWS);
+
+  while (1) {
+    LCD_clearScreen();
+
+    esp_err_t err = dht_read_data(DHT_TYPE_AM2301, DHT_PIN, &humid, &temp);
+
+    if (err != ESP_OK) {
+      ESP_LOGE(tag, "Error: could not read DHT22 Sensor");
+    } else {
+      // printf("Temp: %d.%d C\n", temp / 10, temp % 10);
+      // printf("Humidity: %d.%d%%\n", humid / 10, humid % 10);
+      //
+      float celsius = convertValue(temp);
+      float humidity = convertValue(humid);
+      float fahrenheit = converTemp(celsius);
+
+      sprintf(tempStr, "T: %.1fC / %.1fF", celsius, fahrenheit);
+      sprintf(humidStr, "Humidity: %.1f%%", humidity);
+      LCD_writeStr(tempStr);
+      LCD_setCursor(0, 1);
+      LCD_writeStr(humidStr);
+    }
+
+    vTaskDelay(5000 / portTICK_PERIOD_MS);
+  }
+}
+
+float convertValue(int16_t val) { return val / 10.0f; }
+
+float converTemp(int16_t celsius) { return celsius * (9.0f / 5.0f) + 32.0f; }

004SendData/esp-src/CMakeLists.txt

@@ -0,0 +1,6 @@
+# The following five lines of boilerplate have to be in your project's
+# CMakeLists in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(temp-humidity)

004SendData/esp-src/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "temp-humidity.c" "wifi/wifi_con.c" "json/json_convert.c" "client/client.c"
+                    INCLUDE_DIRS ".")

004SendData/esp-src/main/client/client.c

@@ -0,0 +1,57 @@
+#include "client/client.h"
+#include <lwip/sockets.h>
+
+#define PORT 9000
+const char *address = "192.168.40.88";
+
+int sendJSON(char *json, int len) {
+
+  int fd = 0, res = 0;
+
+  struct sockaddr_in server;
+
+  fd = socket(AF_INET, SOCK_STREAM, 0);
+  if (fd < 0) {
+    return -1;
+  }
+
+  server.sin_family = AF_INET;
+  server.sin_port = htons(PORT);
+
+  res = inet_pton(AF_INET, address, &server.sin_addr);
+  if (res < 0) {
+    close(fd);
+    return -2;
+  }
+
+  res = connect(fd, (struct sockaddr *)&server, sizeof(server));
+  if (res < 0) {
+    close(fd);
+    return -3;
+  }
+
+  res = sendAll(fd, json, len);
+  if (res < 0) {
+    close(fd);
+    return -4;
+  }
+
+  close(fd);
+  return 0;
+}
+
+int sendAll(int sock, char *buf, int len) {
+
+  int total = 0, bytesleft = len, n = 0;
+
+  while (total < len) {
+    n = send(sock, buf + total, bytesleft, 0);
+    if (n < 0) {
+      break;
+    }
+    total += n;
+    bytesleft -= n;
+  }
+
+  return n == -1 ? -1 : 0;
+}

004SendData/esp-src/main/client/client.h

@@ -0,0 +1,7 @@
+#ifndef CLIENT_H
+#define CLIENT_H
+
+int sendJSON(char *json, int len);
+int sendAll(int sock, char *buf, int len);
+
+#endif // !CLIENT_H

004SendData/esp-src/main/idf_component.yml

@@ -0,0 +1,19 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  zorxx/dht: ^1.0.1
+  panigrah/esp32-idf-hd44780: ^0.0.3
+  espressif/cjson: ^1.7.19

004SendData/esp-src/main/json/json_convert.c

@@ -0,0 +1,45 @@
+#include "json/json_convert.h"
+#include <cJSON.h>
+#include <esp_log.h>
+
+char *createJSON(float fahr, float cel, float hum) {
+  char *json = NULL;
+
+  cJSON *fahrenheit = NULL;
+  cJSON *celsius = NULL;
+  cJSON *humidity = NULL;
+
+  cJSON *data = cJSON_CreateObject();
+  if (!data) {
+    return NULL;
+  }
+
+  fahrenheit = cJSON_CreateNumber(fahr);
+  if (!fahrenheit) {
+    cJSON_Delete(data);
+    return NULL;
+  }
+
+  cJSON_AddItemToObject(data, "fahrenheit", fahrenheit);
+
+  celsius = cJSON_CreateNumber(cel);
+  if (!celsius) {
+    ESP_LOGE("JSON", "Failed to create celsius JSON");
+    cJSON_Delete(data);
+    return NULL;
+  }
+
+  cJSON_AddItemToObject(data, "celsius", celsius);
+
+  humidity = cJSON_CreateNumber(hum);
+  if (!humidity) {
+    cJSON_Delete(data);
+    return NULL;
+  }
+
+  cJSON_AddItemToObject(data, "humidity", humidity);
+
+  json = cJSON_Print(data);
+
+  return json;
+}

004SendData/esp-src/main/json/json_convert.h

@@ -0,0 +1,6 @@
+#ifndef JSON_CONVERT_H
+#define JSON_CONVERT_H
+
+char *createJSON(float fahr, float cel, float hum);
+
+#endif // !JSON_CONVERT_H

004SendData/esp-src/main/temp-humidity.c

@@ -0,0 +1,92 @@
+#include "HD44780.h"
+#include "dht.h"
+#include "freertos/idf_additions.h"
+#include "nvs.h"
+#include <esp_err.h>
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "client/client.h"
+#include "wifi/wifi_con.h"
+#include "json/json_convert.h"
+
+#define DHT_PIN 25
+
+#define LCD_ADDR 0x27
+#define SDA_PIN 21
+#define SCL_PIN 22
+#define LCD_ROWS 16
+#define LCD_COLS 2
+
+float convertValue(int16_t val);
+float converTemp(int16_t celsius);
+
+void app_main(void) {
+
+  esp_err_t status = nvs_flash_init();
+  if (status == ESP_ERR_NVS_NO_FREE_PAGES ||
+      status == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+    ESP_ERROR_CHECK(nvs_flash_erase());
+    status = nvs_flash_init();
+  }
+  ESP_ERROR_CHECK(status);
+
+  status = initWifi();
+  if (status == WIFI_FAILURE) {
+    ESP_LOGE(WIFI_TAG, "Failed to connect to Wifi. Exiting");
+    return;
+  } else {
+    ESP_LOGI(WIFI_TAG, "Connected to Wifi Successfully");
+  }
+
+  const char *tag = "TEMP_HUMID";
+  int16_t temp, humid;
+  char tempStr[32], humidStr[32];
+  ESP_LOGI(tag, "Starting our temp/humidity readings");
+  LCD_init(LCD_ADDR, SDA_PIN, SCL_PIN, LCD_COLS, LCD_ROWS);
+
+  while (1) {
+    LCD_clearScreen();
+
+    esp_err_t err = dht_read_data(DHT_TYPE_AM2301, DHT_PIN, &humid, &temp);
+
+    if (err != ESP_OK) {
+      ESP_LOGE(tag, "Error: could not read DHT22 Sensor");
+    } else {
+      // printf("Temp: %d.%d C\n", temp / 10, temp % 10);
+      // printf("Humidity: %d.%d%%\n", humid / 10, humid % 10);
+      //
+      float celsius = convertValue(temp);
+      float humidity = convertValue(humid);
+      float fahrenheit = converTemp(celsius);
+
+      sprintf(tempStr, "T: %.1fC / %.1fF", celsius, fahrenheit);
+      sprintf(humidStr, "Humidity: %.1f%%", humidity);
+      LCD_writeStr(tempStr);
+      LCD_setCursor(0, 1);
+      LCD_writeStr(humidStr);
+
+      // store in JSON object
+      char *json = createJSON(fahrenheit, celsius, humidity);
+      if (!json) {
+        ESP_LOGE("JSON", "Error creating JSON string");
+      } else {
+        ESP_LOGI("JSON", "JSON String %s", json);
+        int len = strlen(json);
+        int res = sendJSON(json, len);
+        if (res < 0) {
+          ESP_LOGE("CLIENT", "Failed to send JSON: %d", res);
+        }
+      }
+    }
+    vTaskDelay(5000 / portTICK_PERIOD_MS);
+  }
+}
+
+float convertValue(int16_t val) { return val / 10.0f; }
+
+float converTemp(int16_t celsius) { return celsius * (9.0f / 5.0f) + 32.0f; }

004SendData/esp-src/main/wifi/wifi_con.c

@@ -0,0 +1,79 @@
+#include "wifi_con.h"
+#include "creds.h"
+#include "esp_netif_types.h"
+#include "esp_wifi_types_generic.h"
+
+static void wifiEventHandler(void *arg, esp_event_base_t eventBase,
+                             int32_t eventId, void *eventData) {
+  static int retryNum = 0;
+  if (eventBase == WIFI_EVENT && eventId == WIFI_EVENT_STA_START) {
+    ESP_LOGI(WIFI_TAG, "Connecting to WiFi...");
+    esp_wifi_connect();
+  } else if (eventBase == WIFI_EVENT &&
+             eventId == WIFI_EVENT_STA_DISCONNECTED) {
+    if (retryNum < MAX_FAILURES) {
+      ESP_LOGI(WIFI_TAG, "retrying to connect.. %d", retryNum);
+      esp_wifi_connect();
+      retryNum++;
+    } else {
+      xEventGroupSetBits(wifiEventGroup, WIFI_FAILURE);
+    }
+  }
+}
+
+static void ipEventHandler(void *arg, esp_event_base_t eventBase,
+                           int32_t eventId, void *eventData) {
+  if (eventBase == IP_EVENT && eventId == IP_EVENT_STA_GOT_IP) {
+    ip_event_got_ip_t *event = (ip_event_got_ip_t *)eventData;
+    ESP_LOGI(WIFI_TAG, "IP Address Assigned: " IPSTR,
+             IP2STR(&event->ip_info.ip));
+    xEventGroupSetBits(wifiEventGroup, WIFI_SUCCESS);
+  }
+}
+
+esp_err_t initWifi() {
+
+  wifiEventGroup = xEventGroupCreate();
+
+  ESP_ERROR_CHECK(esp_netif_init());
+
+  ESP_ERROR_CHECK(esp_event_loop_create_default());
+  esp_netif_create_default_wifi_sta();
+
+  wifi_init_config_t config = WIFI_INIT_CONFIG_DEFAULT();
+  ESP_ERROR_CHECK(esp_wifi_init(&config));
+
+  esp_event_handler_instance_t instanceWIFI;
+  esp_event_handler_instance_t instanceGotIP;
+
+  ESP_ERROR_CHECK(esp_event_handler_instance_register(
+      WIFI_EVENT, ESP_EVENT_ANY_ID, &wifiEventHandler, NULL, &instanceWIFI));
+
+  ESP_ERROR_CHECK(esp_event_handler_instance_register(
+      IP_EVENT, IP_EVENT_STA_GOT_IP, &ipEventHandler, NULL, &instanceGotIP));
+
+  wifi_config_t wifiConfig = {.sta = {
+                                  .ssid = SSID,
+                                  .password = WIFI_PASS,
+                                  .threshold.authmode = WIFI_AUTH_WPA2_PSK,
+                                  .sae_pwe_h2e = WPA3_SAE_PWE_BOTH,
+                              }};
+
+  ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
+  ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifiConfig));
+  ESP_ERROR_CHECK(esp_wifi_start());
+
+  ESP_LOGI(WIFI_TAG, "WiFi init station complete");
+
+  EventBits_t bits =
+      xEventGroupWaitBits(wifiEventGroup, WIFI_SUCCESS | WIFI_FAILURE, pdFALSE,
+                          pdFALSE, portMAX_DELAY);
+
+  if (bits & WIFI_SUCCESS) {
+    return WIFI_SUCCESS;
+  } else if (bits & WIFI_FAILURE) {
+    return WIFI_FAILURE;
+  } else {
+    return WIFI_FAILURE;
+  }
+}

004SendData/esp-src/main/wifi/wifi_con.h

@@ -0,0 +1,21 @@
+#ifndef WIFI_CON_H
+#define WIFI_CON_H
+
+#include <esp_event.h>
+#include <esp_log.h>
+#include <esp_system.h>
+#include <esp_wifi.h>
+#include <freertos/event_groups.h>
+#include <nvs_flash.h>
+
+#define MAX_FAILURES 10
+#define WIFI_TAG "WIFI"
+static EventGroupHandle_t wifiEventGroup;
+
+#define WIFI_SUCCESS BIT0
+#define WIFI_FAILURE BIT1
+
+// NEW FUNC DEFS
+esp_err_t initWifi();
+
+#endif // !WIFI_CON_H

004SendData/server-src/:

@@ -0,0 +1,68 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define PORT 9000
+#define BUFFER_SIZE 1024
+
+int main(int argc, char **argv) {
+  int serverSocket;
+  struct sockaddr_in serverAddr;
+
+  if ((serverSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+    perror("socket failed");
+    exit(EXIT_FAILURE);
+  }
+
+  serverAddr.sin_family = AF_INET;
+  serverAddr.sin_addr.s_addr = INADDR_ANY;
+  serverAddr.sin_port = htons(PORT);
+
+  if (bind(serverSocket, (struct sockaddr *)&serverAddr, sizeof serverAddr) <
+      0) {
+    perror("bind failed");
+    exit(EXIT_FAILURE);
+  }
+
+  if (listen(serverSocket, 5) < 0) {
+    perror("listen failed");
+    exit(EXIT_FAILURE);
+  }
+
+  printf("Server listening on port %d\n", PORT);
+  while (1) {
+
+    struct sockaddr_in clientAddr;
+    socklen_t clientAddr_len = sizeof clientAddr;
+    int *clientSocket = malloc(sizeof(int));
+
+    if ((*clientSocket = accept(serverSocket, (struct sockaddr *)&clientAddr,
+                                &clientAddr_len)) < 0) {
+      perror("accept failed");
+      continue;
+    }
+
+    printf("Connected\n");
+
+    char buf[BUFFER_SIZE];
+    int bytes = recv(*clientSocket, buf, sizeof buf, 0);
+    if (bytes < 0) {
+      perror("error recv data from client");
+      continue;
+    }
+
+    // strip the header
+    char *data = strstr(buf, "\r\n\r\n");
+    if (data) {
+      printf("parsed data %s\n", data);
+    }
+
+    close(*clientSocket);
+    printf("disconnected client.\n");
+  }
+
+  close(serverSocket);
+  return 0;
+}

004SendData/server-src/init.sql

@@ -0,0 +1,6 @@
+create table Stats (
+  Id integer primary key not null,
+  Fahrenheit real not null,
+  Celsius real not null,
+  Humidity real not null
+);

004SendData/server-src/server.c

@@ -0,0 +1,161 @@
+#include <arpa/inet.h>
+#include <cjson/cJSON.h>
+#include <sqlite3.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define PORT 9000
+#define BUFFER_SIZE 1024
+
+typedef struct ESPData {
+  double celsius;
+  double fahrenheit;
+  double humidity;
+} ESPData;
+
+int parseJSON(char buffer[BUFFER_SIZE], ESPData *espData);
+sqlite3 *initDB();
+int storeData(sqlite3 *db, ESPData espData);
+
+int main(int argc, char **argv) {
+
+  sqlite3 *db = initDB();
+  if (!db) {
+    exit(EXIT_FAILURE);
+  }
+
+  int serverSocket;
+  struct sockaddr_in serverAddr;
+
+  if ((serverSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+    perror("socket failed");
+    exit(EXIT_FAILURE);
+  }
+
+  serverAddr.sin_family = AF_INET;
+  serverAddr.sin_addr.s_addr = INADDR_ANY;
+  serverAddr.sin_port = htons(PORT);
+
+  if (bind(serverSocket, (struct sockaddr *)&serverAddr, sizeof serverAddr) <
+      0) {
+    perror("bind failed");
+    exit(EXIT_FAILURE);
+  }
+
+  if (listen(serverSocket, 5) < 0) {
+    perror("listen failed");
+    exit(EXIT_FAILURE);
+  }
+
+  printf("Server listening on port %d\n", PORT);
+  while (1) {
+
+    struct sockaddr_in clientAddr;
+    socklen_t clientAddr_len = sizeof clientAddr;
+    int *clientSocket = malloc(sizeof(int));
+
+    if ((*clientSocket = accept(serverSocket, (struct sockaddr *)&clientAddr,
+                                &clientAddr_len)) < 0) {
+      perror("accept failed");
+      continue;
+    }
+
+    printf("Connected\n");
+
+    // Receive from Client
+    char buf[BUFFER_SIZE];
+    int bytes = recv(*clientSocket, buf, sizeof buf, 0);
+    if (bytes <= 0) {
+      perror("failed to recv from client");
+      continue;
+    }
+    printf("raw data: %s\n", buf);
+
+    // Parse JSON
+    ESPData espData;
+    if (parseJSON(buf, &espData) == 0) {
+      printf("Fahrenheit: %.2f, Celsius: %.2f, Humidity: %.2f\n",
+             espData.fahrenheit, espData.celsius, espData.humidity);
+
+      storeData(db, espData);
+    }
+
+    close(*clientSocket);
+    printf("disconnected client.\n");
+  }
+
+  close(serverSocket);
+  return 0;
+}
+
+int parseJSON(char buffer[BUFFER_SIZE], ESPData *espData) {
+
+  // char *data = strstr(buffer, "\r\n\r\n");
+  // if (data) {
+  //   data += 4;
+  // } else {
+  //   return -1;
+  // }
+
+  const cJSON *fahr;
+  const cJSON *cel;
+  const cJSON *hum;
+  cJSON *jsonData = cJSON_Parse(buffer);
+
+  fahr = cJSON_GetObjectItem(jsonData, "fahrenheit");
+  if (!fahr || !cJSON_IsNumber(fahr)) {
+    printf("Error: failed to parse fahrenheit\n");
+    cJSON_Delete(jsonData);
+    return -1;
+  }
+
+  cel = cJSON_GetObjectItem(jsonData, "celsius");
+  if (!cel || !cJSON_IsNumber(cel)) {
+    printf("Error: failed to parse celsius\n");
+    cJSON_Delete(jsonData);
+    return -1;
+  }
+
+  hum = cJSON_GetObjectItem(jsonData, "humidity");
+  if (!hum || !cJSON_IsNumber(hum)) {
+    printf("Error: failed to parse humidity\n");
+    cJSON_Delete(jsonData);
+    return -1;
+  }
+
+  espData->fahrenheit = fahr->valuedouble;
+  espData->celsius = cel->valuedouble;
+  espData->humidity = hum->valuedouble;
+
+  cJSON_Delete(jsonData);
+  return 0;
+}
+
+sqlite3 *initDB() {
+  sqlite3 *db = NULL;
+  int res = sqlite3_open("stats.db", &db);
+  if (res != SQLITE_OK) {
+    fprintf(stderr, "Failed to open the db: %s", sqlite3_errmsg(db));
+  }
+
+  return db;
+}
+int storeData(sqlite3 *db, ESPData espData) {
+
+  char sql[256];
+  sprintf(sql,
+          "insert into Stats(Id, Fahrenheit, Celsius, Humidity) values(NULL, "
+          "'%f', '%f', '%f');",
+          espData.fahrenheit, espData.celsius, espData.humidity);
+
+  char *errMsg;
+  int res = sqlite3_exec(db, sql, 0, 0, &errMsg);
+  if (res != SQLITE_OK) {
+    fprintf(stderr, "Could not insert into DB: %s", errMsg);
+    sqlite3_free(errMsg);
+    return -1;
+  }
+  return 0;
+}

005Sonar/main.c

@@ -0,0 +1,94 @@
+#include <driver/i2c_master.h>
+#include <esp_err.h>
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <portmacro.h>
+#include <ssd1306.h>
+#include <stdio.h>
+#include <ultrasonic.h>
+
+// defines for sonar sensor
+#define TRIGGER 19
+#define ECHO 18
+
+// defines for i2c display
+#define I2C_HOST 0
+#define SDA 22
+#define SCL 21
+#define RESET_PIN -1
+#define I2C_HW_ADDR 0x3C
+#define LCD_H 128
+#define LCD_W 64
+
+void displayData(ssd1306_config_t *cfg, ssd1306_handle_t *handle, float data) {
+
+  ESP_ERROR_CHECK(ssd1306_clear(*handle));
+  ssd1306_draw_rect(*handle, 0, 0, 128, 4, true);
+
+  char buf[64];
+  sprintf(buf, "Distance: %.2f", data);
+
+  ESP_ERROR_CHECK(ssd1306_draw_text(*handle, 0, 20, buf, true));
+  ESP_ERROR_CHECK(ssd1306_draw_rect(*handle, 0, 40, 128, 4, true));
+  ESP_ERROR_CHECK(ssd1306_display(*handle));
+}
+
+void app_main(void) {
+
+  i2c_master_bus_config_t bus_cfg = {
+      .i2c_port = I2C_HOST,
+      .sda_io_num = SDA,
+      .scl_io_num = SCL,
+      .clk_source = I2C_CLK_SRC_DEFAULT,
+      .glitch_ignore_cnt = 0,
+      .flags.enable_internal_pullup = true,
+  };
+  i2c_master_bus_handle_t bus = NULL;
+  ESP_ERROR_CHECK(i2c_new_master_bus(&bus_cfg, &bus));
+
+  ssd1306_config_t cfg = {
+      .width = LCD_H,
+      .height = LCD_W,
+      .fb = NULL, // let driver allocate internally
+      .fb_len = 0,
+      .iface.i2c =
+          {
+              .port = I2C_HOST,
+              .addr = I2C_HW_ADDR,   // typical SSD1306 I2C address
+              .rst_gpio = RESET_PIN, // no reset pin
+          },
+  };
+
+  ssd1306_handle_t handle = NULL;
+  ESP_ERROR_CHECK(ssd1306_new_i2c(&cfg, &handle));
+
+  const ultrasonic_sensor_t sensor = {.trigger_pin = TRIGGER, .echo_pin = ECHO};
+  const TickType_t duration = 500 / portTICK_PERIOD_MS;
+
+  ultrasonic_init(&sensor);
+  while (true) {
+    float distance = 0;
+    esp_err_t res = ultrasonic_measure(&sensor, 500, &distance);
+    if (res != ESP_OK) {
+      printf("Error %d: ", res);
+      switch (res) {
+      case ESP_ERR_ULTRASONIC_PING:
+        printf("Cannot ping (device is in invalid state)\n");
+        break;
+      case ESP_ERR_ULTRASONIC_PING_TIMEOUT:
+        printf("Ping timeout (no device found)\n");
+        break;
+      case ESP_ERR_ULTRASONIC_ECHO_TIMEOUT:
+        printf("Echo timeout (i.e. distance too big)\n");
+        break;
+      default:
+        printf("%s\n", esp_err_to_name(res));
+      }
+    } else {
+      displayData(&cfg, &handle, (distance * 100));
+      printf("Distance: %.2f cm\n", distance * 100);
+    }
+    vTaskDelay(duration);
+  }
+}

README.md

@@ -0,0 +1,5 @@
+# Embedded Tutorials
+
+Tutorials covering the ESP32, STM32, Arduino, Raspberry PI, etc
+
+