5 Parsing the Raw Data Stream

5.1 Capture startup stream

First, turn off the Bluefly device. Second, launch:

sudo minicom --baudrate=115200 --device=/dev/ttyUSB0 --capturefile=bluefly.out

Third, turn on Bluefly. After it started, turn it off again. Finally, press Ctrl-A and ‘X’ to exit minicom. To see the startup stream, call:

$ head bluefly.out 

Bluefly Power On
BFV 22.2 566
BlueFlyVario_BLUETOOTH_GPS_IGC_22.2.566
BST BFK BFL BFP BAC BAD BTH BFQ BFI BSQ BSI BFS BOL BOS BRM BVL BOM BOF BQH BRB BPT BUR BLD BR2 BHV BHT BBZ BZT BSM BUP BTT BDM BQS BGL BSN BFN BMP BPN
SET 13622 100 20 1 1 1 180 1000 100 400 100 200 5 190 100 1000 0 1 21325 51 1 0 0 624 20 3600 0 60 100 0 2000 0 0 1 1511 93 50 "NKN"
SPI_Flash JDEC:BF 26 43
$PGACK,SW_INI_ANT_INPUT_OK*31
$PMTK011,MTKGPS*08
$PMTK010,001*2E

This tells us we’re running firmware v22.2 release 566. From https://www.blueflyvario.com/files/v22/, we can see that BTH_GPS_IGC_22.2.566.hex was released on 2022-10-08.

From FlyingAl (2021), we learn that pressure data is reported as PRS <hexint>, e.g.

PRS 18276
PRS 18278
PRS 1827B
PRS 18279

The entries starting with a dollar sign ($) are National Marine Electronics Association (NMEA) sentences¹. Those can be parsed using tools such as Python package pynmea2 (https://github.com/Knio/pynmea2) and R package nmea (https://github.com/paleolimbot/nmea).

NMEA 0183.↩︎