Muharrem ARSLAN

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Send data to remote server with STM32 and ESP8266-12F

PROJECT DETAIL

Hello,
We are starting our first project, in this project we will send data from Stm32 to a server.
For now I will send a Count value, but in the future we will develop it and send data such as temperature and humidity sensor, adc...etc.

Why are we sending data from Stm32 to a server? What kind of projects can we do? I can hear your questions.

For example, an IOT device must send and receive data, right? This is how smart homes communicate via mobile application.

What is IOT?
Iot is short for Internet of Things, it is a communication network that a physical device creates among themselves.

We can call the communication of a Stm32 and Mobile application Iot.

 

 

Let's come to the construction phase of our project.

 

I will continue with this as I have an STM32F411VE-DISC card, you can use whatever you have on hand.
You can use the Scheme below.

First we open STM32CubeIDE, select file/new/Stm32 projects and start a new project.

We choose the MCU from the page that opens.

 

 

After choosing the MCU, our project appears.

 

 

1- we make the clock settings.

 

 

2- We make the Usart settings.

 

 

3- We are setting the GPIO. I added 1 led here, when data is sent, the led will flash.

 

 

 

That's it for your project configuration, let's write code now :)

 

Main.c file.

 

#include "main.h"
#include
#include
#include "stm32f4xx_hal_uart.h"

#define Wifi_name "Wifi-name"
#define Wifi_pass "Wifi-pass"
#define Server "Server" /*example : 192.168.1.2*/
char Tx_buffer[250];
char Rx_buffer[500];
int Rx_indx;
char *read;

UART_HandleTypeDef huart1;
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);
void ESP8266_INIT();
void Send_data(int32_t value);
void clear_Rxbuffer();

int main(void) {

    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_USART1_UART_Init();
    /*Send ESP8266 commands*/
    ESP8266_INIT();
    while (1) {
        int cnt;
        Send_data(cnt++); /*Our meter data to be sent */
        HAL_Delay(5000);
    }
}
/* Clear Rx_Buffer */
void clear_Rxbuffer() {
    for (int i = 0; i < 500; i++)
        Rx_buffer[i] = 0;
    Rx_indx = 0;
}
/* Esp8266 start */
void ESP8266_INIT() {
    sprintf(Tx_buffer, "AT+RST\r\n");
    HAL_UART_Transmit_IT(&huart1, (uint8_t*) Tx_buffer, strlen(Tx_buffer));
    HAL_Delay(3000);
    clear_Rxbuffer();
    do {
        sprintf(Tx_buffer, "AT\r\n");
        HAL_UART_Transmit_IT(&huart1, (uint8_t*) Tx_buffer, strlen(Tx_buffer));
        HAL_Delay(500);
        read = strstr(Rx_buffer, "OK");
    } while (read == NULL);
    clear_Rxbuffer();

    do {
        sprintf(Tx_buffer, "AT+CWMODE=1\r\n");
        HAL_UART_Transmit_IT(&huart1, (uint8_t*) Tx_buffer, strlen(Tx_buffer));
        HAL_Delay(500);
        read = strstr(Rx_buffer, "OK");
    } while (read == NULL);
    clear_Rxbuffer();

    char str[100];
    do {
        strcpy(str, "AT+CWJAP=\"");
        strcat(str, Wifi_name);
        strcat(str, "\",\"");
        strcat(str, Wifi_pass);
        strcat(str, "\"\r\n");
        sprintf(Tx_buffer, "%s", str);
        HAL_UART_Transmit_IT(&huart1, (uint8_t*) Tx_buffer, strlen(Tx_buffer));
        HAL_Delay(6000);
        read = strstr(Rx_buffer, "OK");
    } while (read == NULL);
    clear_Rxbuffer();
}

/* Esp8266 send data */
void Send_data(int32_t value) {
    char local_txA[200];
    char local_txB[50];
    int len;

    HAL_GPIO_WritePin(GPIOD, GPIO_PIN_12, GPIO_PIN_SET);
    clear_Rxbuffer();
    do {
        sprintf(Tx_buffer, "AT+CIPSTART=\"TCP\",\"%s\",80\r\n", Server);
        HAL_UART_Transmit_IT(&huart1, (uint8_t*) Tx_buffer, strlen(Tx_buffer));
        HAL_Delay(100);
        read = strstr(Rx_buffer, "CONNECT");
    } while (read == NULL);
    clear_Rxbuffer();
    do {
        sprintf(local_txA,
                "GET /valua.php?value=%ld HTTP/1.0\r\nHost: %s\r\n\r\n", value,
                Server);
        len = strlen(local_txA);
        sprintf(local_txB, "AT+CIPSEND=%d\r\n", len);
        HAL_UART_Transmit_IT(&huart1, (uint8_t*) local_txB, strlen(local_txB));
        HAL_Delay(100);
        read = strstr(Rx_buffer, ">");
    } while (read == NULL);
    HAL_UART_Transmit_IT(&huart1, (uint8_t*) local_txA, strlen(local_txA));
    HAL_GPIO_WritePin(GPIOD, GPIO_PIN_12, GPIO_PIN_RESET);
}

void SystemClock_Config(void) {
    RCC_OscInitTypeDef RCC_OscInitStruct = { 0 };
    RCC_ClkInitTypeDef RCC_ClkInitStruct = { 0 };

    __HAL_RCC_PWR_CLK_ENABLE();
    __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSEState = RCC_HSE_ON;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLM = 7;
    RCC_OscInitStruct.PLL.PLLN = 336;
    RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
    RCC_OscInitStruct.PLL.PLLQ = 8;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
        Error_Handler();
    }
    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_SYSCLK
            | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK) {
        Error_Handler();
    }
}

static void MX_USART1_UART_Init(void) {

    huart1.Instance = USART1;
    huart1.Init.BaudRate = 115200;
    huart1.Init.WordLength = UART_WORDLENGTH_8B;
    huart1.Init.StopBits = UART_STOPBITS_1;
    huart1.Init.Parity = UART_PARITY_NONE;
    huart1.Init.Mode = UART_MODE_TX_RX;
    huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
    huart1.Init.OverSampling = UART_OVERSAMPLING_16;
    if (HAL_UART_Init(&huart1) != HAL_OK) {
        Error_Handler();
    }
}

static void MX_GPIO_Init(void) {
    GPIO_InitTypeDef GPIO_InitStruct = { 0 };
    __HAL_RCC_GPIOC_CLK_ENABLE();
    __HAL_RCC_GPIOH_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    __HAL_RCC_GPIOD_CLK_ENABLE();

    HAL_GPIO_WritePin(GPIOD, GPIO_PIN_12, GPIO_PIN_RESET);
    GPIO_InitStruct.Pin = GPIO_PIN_12;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);
}

void Error_Handler(void) {
}

#ifdef  USE_FULL_ASSERT
/**
 * @brief  Reports the name of the source file and the source line number
 *         where the assert_param error has occurred.
 * @param  file: pointer to the source file name
 * @param  line: assert_param error line source number
 * @retval None
 */
void assert_failed(uint8_t *file, uint32_t line)
{
 /* USER CODE BEGIN 6 */
 /* User can add his own implementation to report the file name and line number,
    tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
 /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

 

Then let's open the Stm32f4xx_it.c file and write the necessary codes.

 

#include "main.h"
#include "stm32f4xx_it.h"
char Rx_data[1];

extern UART_HandleTypeDef huart1;

extern char Rx_buffer[500];
extern int Rx_indx;

void SysTick_Handler(void)
{

 HAL_IncTick();

}


void USART1_IRQHandler(void)
{

 HAL_UART_IRQHandler(&huart1);
       uint8_t i;
           if (Rx_data[0] != '\n')
                   {
               Rx_buffer[Rx_indx++] = Rx_data[0]; /*Gelen Dataları Rx_buffer'ın içine at*/
           }
           HAL_UART_Receive_IT(&huart1, (uint8_t*) Rx_data, 1);

}

 

Server side php code.

 

try {
$db = new PDO("mysql:host="server";dbname="dbname";charset=utf8", "db_user", "db_pass");
} catch ( PDOException $e ){
     print $e->getMessage();
}

if (isset($_GET['value'])) {   $value = $_GET['value'];    }

if((isset($value)))
{

$query = $db->prepare("INSERT INTO esp SET value = ?");

 $insert = $query->execute(array("$value"));

if ( $insert ){
    $last_id = $db->lastInsertId();

    $array = array(

        "Status"=>"succesfull",
        "Info" => "1",
    );
    $json = json_encode($array);
    echo $json;
}
}
else {

      $array = array(
          "Status"=>"Data Not Entered!",
          "Info" => "0"
      );

      $json = json_encode($array);
      echo $json;
      die();
}

 

You can also download the project file from here.

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