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flickering rows

Posted: Sun Oct 11, 2009 3:02 pm
by jbergen
I've put together a board which works great except for the bottom two rows of LEDs flicker whenever any one of the LEDs are lit in either row. They still work, it's just a consistent flicker . I've checked for shorts and can't seem to find anything wrong right off the bat. Anything I can check or should be aware of?

Thanks in advance!!

Re: flickering rows

Posted: Mon Jun 07, 2010 2:39 pm
by claybratt
is it the first chip that is connected to your arduino(or whatever microcontroller)? I was able to get rid of it by putting a 1k resistor on the data line. I'm not an electrical expert though.

Re: flickering rows

Posted: Sun Jun 20, 2010 11:23 am
by paul
I'd look for a bad solder joint first, but tying a 10k or 1k resistor to the line also sounds fine to me. It's possible that dataman's library floats the data pin (but I don't know why) after sending data, so that it's a high impedance line. It's also possible that your power supply is noisy (or can't provide enough power, and the power line sag is getting interpreted as data).

Thanks for writing in, I'll keep my eyes out for the source of this. I just made a big sign with one BBB and 8 panels for Maker Faire in San Mateo, and I didn't see any hint of that issue. I did end up with a big honking 12 amp switching power supply though, that cost about $75.

I also have to add that dataman's library was awesome, and I was able to merge three sketches, which included scrolling type and the game of life, with very little effort.

paul