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-   -   Panel dimmer or not? (Garmin) (https://vansairforce.net/community/showthread.php?t=159896)

rvsxer 04-26-2018 11:15 AM

Quote:

Originally Posted by Walt (Post 1255782)
Not so for the GMA245:

Photocell dimming circuitry automatically adjusts the brightness of the annunciators.
Backlighting is controlled by the aircraft lighting bus inputs if the lighting bus is connected.
If the lighting bus is not connected, backlighting is controlled by the photocell.

They changed that, then, which is good. The earlier audio panels had no photocell backlighting control available.

rzbill 04-26-2018 11:23 AM

It's not a big enough nuisance to make me change it, but if did have an opportunity, I would put a panel dimmer on my Garmin 430W. I do have the photocell ramp, offset and minimum values tuned. Night flying levels need to be remarkably dim.
The nuisance time for me is sunrise which I fly quite often. Just before the sun breaches the horizon, but the sky is considerably lighter, the garmin is too dark. That period lasts maybe 15 minutes max. I guess I might be able to play with the offset or ramp settings some more but it would be nice to just twist a knob.

EDIT Like Walt, I do have a couple of home made dimmers in the cabin. They are for LED floods that illuminate toggle switches and separately a handful of Nulites. On each I used a 50K pot, a 5K resistor and an LM317T voltage regulator. All built and glued to the pot. Gives a 10 to 1 turn down ratio. I think I have seen example schematics of this simple circuit on EAA or elsewhere. The LM317T package usually has it too.

sglynn 04-26-2018 11:47 AM

Dimmer
 
I just did my Panel with Dynon and Garmin GPS. And I'm using the Advanced Control Module which is similar to VPX. Quick Panel by Advanced. But I also have lighted rocker switches. At first I had the rocker switch lights wired to the dimmer from the ACM (VP-X). It dimmed the rockers too far, too dim, almost off. It dimmed the Dynon screens appropriately. There is no software setting to set the dim level different between screens and the rocker lights. So I have a dimmer for other lighting. Now the screens can dim the way they want to and I can manual dim the rocker switches and any other internal lighting I decide to add. I may add a ceiling light, or floor lights and they will come off the dimmer switch.

Yes do the dimmer.

Electrogunner 04-26-2018 12:02 PM

Dimmers
 
Well. I almost had my panel ready to install until this thread popped up. Hmmm. Thinking if I should add dimmers now. G900X. I think I have a couple potentiometers laying around somewhere.

KeithB 04-27-2018 08:01 AM

I have a full Garmin panel. I chose to use the GAD 27 with 3 input pots (10k as Walt described). The GAD 27 has 6 dimming circuits (customizable) controlled from the 3 inputs - 3 with voltage control for screens inputs (G3X and GTN 650 in my case) and 3 with pulse width modulation for LED circuits. I use Pot 1 for screen, Pot 2 for switches (LED lights) and buttons (such as GMA 245 audio panel), and Pot 3 for a glareshield-mounted LED strip for both panel lighting (red) and cabin lighting (white).

As others have said, sometimes the photocell just doesn't get it right (dusk and dawn in particular, and during setup before taxi in the dark). Also, the custom profiles can be set to allow an "off" setting allowing me to turn off all panel switch lighting and the glareshield strip during night cruise.


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