Hello Vlad,

After doing a lot of different testings I´m still having a strange behaviour on my LEDs:

1) a lot of flickering (for the annunciators that should light)
2) some Annunciators light up that shouln´t.
3) some Annunciator, that should not go on, light up very little, as they would shine a little tiny bit of light.

Notes (could be issues maybe?):

a) I have different LEDs colors (with different forward voltages 2,1V/3,2V) on the same Driver
b) I´m powering the drivers with Arduino +5V
c) I ordered new DM13A drivers from another source (DIP format). the actual ones came from china with SSOP24 format but with 1,0mm spacing, so had to get some rare Adapter boards... well lets see if that changes something
d) I´m using different Rext resistances, but they dont seem to change the brightness..also tried with potentiometer. Brightness is only affected when I slightly change the LED Voltage Power source between 4,5V and 6,5V.

I am building a complete Overhead for the B737-800 with SimVim. Each Annunciator consists of 2 LEDs in series connection.  5V 20A Supply Power used (Also powered up and set to 6,6V)  for all annunciators.

Would appreciate your help a lot!

Thank you for the great plugin!

P.D.: some mappings are still missing in the configurator for the Overhead panel. If you want I could help you by highlighting for you in order to complete the panels.

Diego.
in Wiring, Powering by

1 Answer

0 votes

Diego,
First, add the pull-down resistor to each driver directly between driver chip pin 3 and GND (1-3 kOhm, yellow wire on this picture):



Vlad
 

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0

Regarding your notes:

a) I have different LEDs colors (with different forward voltages 2,1V/3,2V) on the same Driver

It doesn't matter. If your LEDs has different brightness just use additional serial resistors for  the LEDs that are too bright.

b) I´m powering the drivers with Arduino +5V

It's normal. I power all my test platform (including displays) from one USB hub source (that is inside of my 27" monitor).

c) I ordered new DM13A drivers from....

It doesn;t matter what drivers you use, all they are the same, the difference is in maximum current and the convenience to use.

d) I´m using different Rext resistances, but they dont seem to change the brightness..also tried with potentiometer. Brightness is only affected when I slightly change the LED Voltage Power source between 4,5V and 6,5V.

The Rext resistor defines the current for all LEDs, and the less it's value, the higher  current goes through the LEDs, and it should be brighter, and vice versa.

The current is defined by driver output voltage on each of 16 outputs. If you have different LEDs work current, you can set the maximum allowable for your LEDs current by Rext resistor, and add a serial resistor to some LEDs which are brighter than others.

Vlad


 

0

Hi Vlad, 

First of all, I have to thank you for this impressive detailed answer and for your preocupation to solve my issue. I don´t see this very often with other developers, and I have to say-> Chapeau!

I have added the pull-down resistor (1, 2 and 3kOhm respectively) on the #3 pin and had the same flickering results and LED lighting that should not light as before. -> Could you please explain to me (for learning purposes) what is this pull-down resistor doing exactly?

I have to add that after that, I received my new DM13A Drivers with DIP configuration (no soldering on adapter board needed for testing) and wired up everything and voilá! everything is working perfectly.

So I´m guessing, that my newbie soldering skills have somewhat failed when I soldererd the SSOP24 chip on the adapter board and messed up the connections, or maybe the adapter boards I got are bad quality...? (probably the first one frown).

Thank you for your suggestions on adding serial resistors to improve Brightness on different Color LEDs. I might be trying that out aswell.

With nothing more to add, but to thank your support and to welcome this amazing plugin!!

Best Regards,

Diego.

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