ESP32 Project: Visitor Flow Rate Counter

In this ESP32 project, we will make a visitor flow rate counter with ESP32, using the MakePython ESP32 and MakePython A9G GPRS/GPS expansion board.

Last weekend I went to my friend’s milk tea shop to help because the business was so hot that he didn't arrange enough clerks. In order to reasonably arrange the working hours of the clerk, I Build a counter to help him count the changes in the number of customers.

1. Materials

1.1 Hardware

• MakePython ESP32, a powerful, generic WiFi + BLE MCU module target MicroPython learners & developers.
• MakePython A9G GPRS/GPS Expansion, a GPS/GPRS expansion board for MakePython.
• Micro USB cable
• Micro SD Card

1.2 Software

• Arduino

2. How the Visitor Flow Rate Counter Works

3. How to Connect the Hardware

4. Software and Code

4.1 ESP32 Support

4.2 Code

• Sniffer init

void wifi_sniffer_init(void)
{
  nvs_flash_init();
  tcpip_adapter_init();
  ESP_ERROR_CHECK(esp_event_loop_init(event_handler, NULL));
  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
  ESP_ERROR_CHECK(esp_wifi_init(&cfg));
  ESP_ERROR_CHECK(esp_wifi_set_country(&wifi_country)); /* set country for channel range [1, 13] */
  ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
  ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_NULL));
  ESP_ERROR_CHECK(esp_wifi_start());
  esp_wifi_set_promiscuous(true);
  esp_wifi_set_promiscuous_rx_cb(&wifi_sniffer_packet_handler);
}<br>

int check_mac_only(const uint8_t addr3[6])
{
  for (char i = 0; i < mac_count; i++)
  {
    bool flag = true;
    for (char j = 0; j < 6; j++)
    {
      if (mac_lib[i][j] != addr3[j])
      {
        flag = false;
        break;
      }
    }
    if (flag == true)
      return 0;
  }
  for (char j = 0; j < 6; j++)
  {
    mac_lib[mac_count][j] = addr3[j];
  }
  mac_count++;
  return 1;
}

• Writing files to SD card

void writeFile(fs::FS &fs, String path, String message)
{
  Serial.println("Writing file: " + path);
  File file = fs.open(path, FILE_WRITE);
  if (!file)
  {
    Serial.println("Failed to open file for writing");
    return;
  }
  if (file.println(message))
  {
    Serial.println("File written");
  }
  else
  {
    Serial.println("Write failed");
  }
  file.close();
}