Arduino/Elegoo Mega 2560 | MobiFlight | Page 1

undone canopy Aug 30, 2024, 7:18 AM

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Hi.....Can someone advise.
I have 5 mega boards for the forward overhead panel for the 737 sim, I have clustered the annunciators across two boards.
98 Annunciators with two LED's in each wired in parallel with a 220 ohm resistor on the cathode leg. The LED's are 2v 20mA, albeit i have not made the annunciators up yet as I'm open to suggestion lol.
I am aware that the annunciators will not all be on at the same time but when you put the cockpit into test mode i.e. the "test all lights" switch, the boards are going to get a work out/Blow, would it be an idea to spread the annunciators across all 5 boards ? thanks for any advice
Cheers
J

stark scarab Aug 30, 2024, 12:22 PM

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You got to do the math and allocate your circuits respecting the current draw limits for each board and pin. I think you are above the limits even for five boards.
Consider using led driver chips like the DM13A. That can allow you to power 16 annunciators with external power. You can daisy chain two chips and you can have up to 6 chains per Arduino board.

civic gazelle Aug 30, 2024, 1:32 PM

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Sorry, I had to delete my message. I need to change a couple things on the design. It is way too big.

undone canopy Aug 30, 2024, 1:49 PM

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So i have been told that if i spread at max 20 of the annunciators across the 5 boards i should be ok, I have tested the leds and the cluster of one annunciator is 12mA ish

versed silo Aug 30, 2024, 1:54 PM

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yeah spreading over Arduinos is one good idea

undone canopy Aug 30, 2024, 5:58 PM

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its going to be a lot of wiring and soldering but this is the one panel that's really busy

vernal swallow Oct 15, 2024, 10:35 PM

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@undone canopy do you have any other questions in this topic or shall I mark it as solved?

#Arduino/Elegoo Mega 2560