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Hello, first I introduce myself since it is my first intervention in this forum. My name is Pedro, I am from Spain, I have an ultralight plane and I like to fly and program my own instruments for my plane.
I am building the Bluetooth adapter to be able to send the autopilot information from Skydemon to an old TRUTRAK DIGIFLIGHT II autopilot but it is not capable of recognizing the NMEA sentences that the Skydemon sends it.
I have been analyzing the NMEA sentences that the Garmin GPSMAP 296 GPS sends and they are like this:
$GPRMC,111231,A,4041.3941,N,00036.84755,W,0.0,227.3,190225,0.8,W,D*11
$GPRMB,A,0.00,R,,EDNT,4859.7560,N,01053.0926,E,656.923,44.7,,V,D*41
$GPRMC,111232,A,4041.3941,N,00036.84755,W,0.0,227.3,190225,0.8,W,D*12
$GPRMB,A,0.00,R,,EDNT,4859.7560,N,01053.0926,E,656.923,44.7,,V,D*41
$GPRMC,111233,A,4041.3941,N,00036.84755,W,0.0,227.3,190225,0.8,W,D*13
$GPRMB,A,0.00,R,,EDNT,4859.7560,N,01053.0926,E,656.923,44.7,,V,D*41
However, the NMEA sentences that Skydemon currently throws are like this:
$GPRMC,111343,A,41$GPRMB,A,0.76,R,OR$GPRMC,111344,A,41$GPRMB,A,0.76,R,OR$GPRMC,111345,A,41$GPRMB,A,0.76,R,OR$GPRMC,111346,A,41$GPRMB,A,0.76,R,OR$GPRMC,111347,A,41$GPRMB,A,0.76,R,OR$GPRMC,111348,A,41$GPRMB,A,0.76,R,OR$GPRMC,111349,A,41$GPRMB,A,0.76,R,OR$GPRMC,111350,A,41$GPRMB,A,0.76,R,OR$GPRMC,111351,A,41$GPRMB,A,0.76,R,OR$GPRMC,111352,A,41$GPRMB,A,0.76,R,OR$GPRMC,111353,A,41$GPRMB,A,0.76,R,OR$GPRMC,111354,A,41$GPRMB,A,0.76,R,OR
That is, the NMEA frames of the Skydemon are missing all the information fields and also do not end with CR+LF (0x0D + 0x0A) so the TRUTRAK autopilot is not able to interpret the NMEA sentences correctly.
Could you please check and correct it.
PD.-
Thank you very much Tim for having implemented the new Bluetooth functions, it is something that has been needed for a long time to be able to use Skydemon as the main route planning source.
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Group: Forum Members
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+x+xAll,
I was very excited when I read about the feature in the Skydemon release note, went right into ordering parts and figured I share the experience here.
Top 1 priority for me was to get the radio (f.u.n.k.e. ATR833-II) connected. So I designed a 3d case that perfectly fits on top of the original Sub-D connector housing and uses the existing screw holes (only needed slightly longer screws). Once mounted, it sits below the connector at the back of the radio and doesn't block anything else / basically uses the same space.
I decided to use a HM-18 BLE to serial module. It is very power efficient and therefore I could easily use the 5V the radio provides on the Sub-D connector. The HM-18 is outputting TTL serial, hence I added a MAX3232 converter to provide the proper RS232 levels the radio expects.
Put everything together and it worked right away. For me it's almost a killer feature in Skydemon as it makes my life so much more simple during flight.
A big thx to Tim and his team for adding this feature!
Hi moefly,
according to HM-18 datasheet the power supply voltage is from 1.9V to 3.7V. The ATR833 has 5V output. Do you use a voltage converter or do you just run out of specs?
Regards, Tobi
Hi Tobi,
sorry for the super late reply, didn't see it until now. Think it was already answered in the meantime: The HM-18 module itself is spec'd to work between 3.6-6V, so should be fine with the ATR833 5V output. The serial levels need to be shifted though as the HM-18 uses 3.3V but the ATR833 expects proper RS232 levels, which is why I added a MAX3232 in between. Best Markus
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