MobiFlight Community Support

Hi,

I'm building the Hispapanels MCDU for A320 (FBW mod). As I had to design an adapter board in order to connect the Hispapanels, I thought that it could be wonderful to not only use BRT/DIM buttons to adjuust backlight brightness in the sim (via Mobiflight) but also to adjust backlight in real MCDU, but I'm finding some trouble to find a valid design.

So, my starting point is as follow:

- Both BRT/DIM buttons are connected to GND and to two different MEGA pins
- Integrated LED in MCDU buttons are 12V

My first idea was to use a digital UP/DOWN digital potentiometer (along with a BD139 transistor), but I couldn't find such a potentiometer for 12V. The second design I found used a MOSFET and a capacitor, as in the image below:



However, in that design one of the pushbuttons is connected to 12V which is not the case. I have some electronics background, but not enough to make a redesign of any of the solutions above to match my needs.

Can anybody help me? Thank you very much!!

I thought that it could be wonderful to not only use BRT/DIM buttons to adjuust backlight brightness in the sim (via Mobiflight) but also to adjust backlight in real MCDU,

If you still like to controll also the Virtual System Brightness then the most profitable way is to controll the Real Dimmer ( Mosfet i exepct) via the Virtual System.

Idea;

The 2 Buttons ONLY controll the Virtual Brightness .... means they are just Input Buttons on a Arduino controlled by Mobiflight.
If Buttons are pressed we send a single "Inc or Dec Brightness Command into the virtual Cockpit. ( Like you do already now)

The Brightness of the Real Panel finally is controlled with a Electrical System ( Most use Mosfets as i know). It receive a PWM Signal from Mobiflight that tell it how bright we need the lights.

Finally this signal is done by a LED Output ( On a PWM Pin) .
You Create in MF a Output Config ... And you use as Device this LED Output Pin you define .
Enable PWM Mode in that Config.
Now read the "Brightness Status Variable" from the Sim and use a Formula to bring this Value into the needed 0-255 Format we use for PWM Signals.

Example: ( I not know the Sim Variable value range.... So this is just a example! )
E.g. Sim Brightness is a value of 0-1023 then simply say $/4 .
Result:
If Sim Value = 1023 (Full ) /4 = 255
255 in PWM means 100% .
So your Output send Signal to Mosfet to be Full Bright.

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NOTE:
Most experiece here have "Tuomas" from our Discord Support Team.
Please Contact him on Discord ( Orange Color) He pretty sure can guide you better like me.