12 August 2018

Avionics: Canopy USB power change.

I use a GoPro Hero 6 Black mounted inside the canopy.  To power it, I designed a simple board to provide an available 4 Amps from two USB ports.  I mounted that board to the canopy frame.  However, when connected to that power source, the Hero 6 camera will shut off (actually, it crashes and turns back on in Band-Aid mode), without fail, as soon as I taxi into position on the runway.


Originally, I had a Powerwerx dual USB port between the seats.  It powered the Hero 6 without issue.  However, it created a lot of hash on my GTR-200 transceiver


So I replaced it with one from Blue Sea.  This one did not create hash on the GTR-200.  But, the Hero 6 again would shut off at odd times.


After doing a lot of testing at home, I determined that the Hero 6 is extremely picky on which power source it can accept without crashing.  It even won't accept power from my computer's USB port without crashing.  Since the Powerwerx socket originally worked, I decided to replace my USB board with the Powerwerx socket at the canopy frame.  Using some spare aluminum and angle, I made a quick mount for the socket and attached it to a tooling hole on the C-01405-L Aft Canopy Frame with a nylon screw.



Now the Hero 6 stays on the whole flight and there is no hash on the GTR-200.  That may be because the ground wire for the Powerwerx socket goes to the main ground bus, whilst the ground wire for the Blue Sea socket goes to the aircraft chassis.  So perhaps when the Powerwerx socket was originally between the seats, that grounding setup was the cause of the hash.

View from camera in daytime:


In the nighttime:

Avionics: GMA-240 replaced with GMA-245.

I replaced my GMA-240 with the GMA-245.  I did this because of some of the features the latter includes over the former.  Below I only list those of interest to me - it has additional features not included on the GMA-240:
  • Auto-squelch.
  • Independent music knobs for pilot and co-pilot. 
  • Integrated Bluetooth.
    • Great for music from my phone and for phone calls.
  • 3D audio.
  • Clearance recorder and player.

GMA-245



GMA-240



Though I much prefer it over the GMA-240 I am disappointed with a few things about the -245:
  • It does not include an option for "button tone press".  So when you press buttons, you don't get an audible indication of having done so.  I asked the G3X team to include that option in a future firmware revision.  Based on their response to me, I'm not expecting them to do it.
  • The photocell-based auto-dimming is poorly calibrated.  At night time, the announciator lights are not discernible.  I asked the G3X team to consider adding an option to adjust its sensitivity.  Based on their response to me, I'm not expecting them to do it.
  • It is unable to do a software update via the SD card.  Garmin's G3X support group can provide me no solutions other than to repeat to me what's in the documentation then suggest taking it to a dealer.  My plan is to have my intercom updated in a friend's plane who has a G3X system (the G3X can update the 245 through the CAN connection).

The GMA-245 is not pin-for-pin identical to the GMA-240.  It will work as a direct swap, but some inputs will be remapped to different ones.  The remapped ones, specific to my aircraft,  are shown below (240 to 245).
  • Alert 2 → Alert 4
  • Alert 3 → Alert 2
  • Alert 2,3 Audio In Lo → Alert 3,4 Audio In Lo
  • Mute* On Com Tx In → Discrete 6 Input* (Copilot ICS Key)
  • Com  Swap* In → Discrete 4 Input*
  • Button Press Tone Enable Hi → Reserved
 Wiring maps for both, as connected in my aircraft, are below.

GMA-245 (installed)


GMA-240  (removed)