Arduino ESP32 receive file over BLE (for OTA update)

Question

I want to send a file (bin) from my Xamarin Forms (C#) iOS App over BLE (https://github.com/xabre/xamarin-bluetooth-le) to my ESP32 (Arduino). That file would be a bin file for updating. I found already a solution on how to update the ESP32 out of spiffs (arduino-esp32 do OTA via BLE) but does anyone know how I can receive the file with the ESP32 and save it into spiffs?

(The BLE connection app to esp32 is already fully working, I can send texts, but I don't know how to send files)

Best regards nflug

Answer 1

You have to send the file content as individual bytes and save it to SPIFFS

You can create and write to a binary file using the function below (Arduino code)

void writeBinary(fs::FS &fs, const char * path, uint8_t *dat, int len) {

  //Serial.printf("Write binary file %s\r\n", path);

  File file = fs.open(path, FILE_APPEND);

  if (!file) {
    Serial.println("- failed to open file for writing");
    return;
  }
  file.write(dat, len);
  file.close();
}

Check out the usage here ESP32_BLE_OTA_Arduino.

I have also created an android app to upload the file ESP32_BLE_OTA_Android