Doubled horizontal lines

The Dot Matrix Display (DMD) is a 32x16 array of high-brightness LEDs for visually striking effects. [Product Page]
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carastas
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Joined: Mon Jan 28, 2019 10:03 pm

Doubled horizontal lines

Post by carastas » Mon Jan 28, 2019 10:11 pm

Hi,

I'm trying to create a dog agility timer with the DMD2 library and a Leonardo.

Everything works great except that some horizontal lines are doubled...
I redid the connections and it's the same...

I'd like to use a Leonardo so I can also use a keyboard emulator to write the time in an excel sheet automatically...
(I think it worked better on the Uno, with the DMD not DMD2 library)

Please see here: https://youtu.be/60CkyMZaaiY
some of the lines are 4 leds height... and the font only has 3 leds...

Thank you for your support,
Dan

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stryker
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Joined: Sat Jan 14, 2012 2:44 pm

Re: Doubled horizontal lines

Post by stryker » Tue Jan 29, 2019 5:18 am

Sorry I don't see the issue - did you post the right video in that link?

carastas
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Joined: Mon Jan 28, 2019 10:03 pm

Re: Doubled horizontal lines

Post by carastas » Tue Jan 29, 2019 6:32 am

HI, yes, if you look at the bottom horizontal line it has 4 pixels (leds) with the top one (4th from the bottom) slightly less lit than the bottom 3.

That isn't supposed to be there, Actually now that I look at it some more LEDs are lit that shouldn't be (or the phone camera doesn't sync), but that bottom row is the worst case, as it makes the numbers too think...

Also the 9 in the screenshot attached here has the middle line doubled as well..
https://ibb.co/S060Kgn

Thank you for your time,
Dan

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stryker
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Re: Doubled horizontal lines

Post by stryker » Tue Jan 29, 2019 8:06 am

Hi Dan
I see what you mean now. Is that the only DMD you have? I've had some fail in a different mode to that (rows don't light or the whole row lights) but not in the way that is showing.

To rule out hardware being at fault, does it have imperfections like that showing if you load the standard demo sketch and run that?

Geoff

carastas
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Joined: Mon Jan 28, 2019 10:03 pm

Re: Doubled horizontal lines

Post by carastas » Tue Jan 29, 2019 10:28 am

Hm, good idea, I have another panel at the office, I'll try with that...
Also, I'll try an uno... because it worked ok with the uno, I think, but I'll loose the keyboard capabilities ;(
I think the interrupt timer or something differs from DMD and DMD2 and Uno and Leonardo.

I thought it was something more common, thank you, I'll keep you posted with what I find for future reference.

Dan

carastas
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Joined: Mon Jan 28, 2019 10:03 pm

Re: Doubled horizontal lines

Post by carastas » Tue Jan 29, 2019 6:33 pm

Hi,

I tested with a Nano, and there's no flickering, so I guess it's the Leonardo's fault, but the Nano doesn't have the keyboard.h compatibility. I have to look for another board.

Thank you,
Dan

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stryker
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Re: Doubled horizontal lines

Post by stryker » Tue Mar 05, 2019 10:04 pm

Glad you sorted that out Dan.

Do you need a full keyboard? If you only need to enter characters, and a full size keyboard isn't 100% needed I've used an android app on a phone to send characters via bluetooth as a solution to this. MIT App Inventor makes the app creation straightforward (and the right price) and there are heaps of examples on youtube etc for setting up a Bluetooth module to do the talking.

All the best with your project
Geoff

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