Firmware mode

To switch between modes (i.e. serial output raw from camera, qr codes, others), everytime the ESP32 board is reset it waits for few milliseconds for a character that defines which mode:

while (waitForStreamMode > millis()) {
    if (Serial.available())  // if we receive anything, just switch to another mode
    {
      switch (Serial.read()) {
        case 'q':  // QR code reader mode
          qr_reader_setup();
          for (;;)
            qr_reader_loop();

        case 'm':  // Motion detection
          motion_detection_setup();
          for (;;)
            motion_detection_loop();
...

Check esp32cam_marauder.ino file for the actual code. This makes switching mode easy in the Flipper fap, turning off and on the otg power and sending the corresponding char for which mode we want to use in the app:

furi_hal_power_disable_otg();
furi_delay_ms(200);
furi_hal_power_enable_otg();
furi_delay_ms(500); 
furi_hal_uart_tx(FuriHalUartIdUSART1, (uint8_t[1]){'q'}, 1);
...

Check the companion apps for the actual code.