TTGO T-Beam LoRa Logger

A simple tool to log LoRa communication for further evaluation designed for the TTGO T-Beam.

Functionality

• Continuously validate GPS (set position and date/time)
• Listen for LoRa messages (static configuration, see src/main.cpp:153)
• Save messages and keepalives to internal SPIFFS file system
• Serve internal filesystem via HTTP

Using the logger

WiFi Connection

A WiFi can be configured in the code, where the Logger will try to connect to during bootup. If non successful, it will continue operation on AP mode:

SSID: TTGO T-Beam LoRa Logger
Password: supersicher
IP: 192.168.4.1

Accessing Logfiles

The logfiles are named recv_xxxx.csv, and can be obtained via HTTP GET, e.g. http://192.168.4.1/recv_0000.csv.

Note: A request to the root file is always forwarded to the current logfile written to, hence http://192.168.4.1/ will retrieve the most recent logfile.

The logfile contains the following fields:

• ts:
• gps_sat:
• gps_age:
• lat:
• lon:
• alt:
• cnt:
• len:
• rssi:
• snr:
• freq_err:
• msg:

Resetting Storage

Press and hold the user button 3s during bootup. A message on the serial console will show up, and inform, that the internal storage has been deleted.

Caveats

The internals storage is limited to 4 MB, which is easily filed with messages, since a lot of metadata is transmitted. Therefore it is only useful for shorter experiments and should be formatted afterwards.

Time.h include building error

Due to the non-central structure of embedded programming in C, a problem occurs while using the Time library. The Time.h header is offered by the ESP-IDF as well as the library and thus leads to confusion. The error can be fixed by just moving the regarding Library away:

mv .pio/libdeps/esp32dev/Time_ID44/Time.h .pio/libdeps/esp32dev/Time_ID44/_Time.h