bugfight

Frequent Writer
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Everything posted by bugfight

  1. Help with LED matrix

    that is interesting, if you're 595s aren't overheating on one board with all lit, you must be ok. maybe those leds like a +3v supply?  hm maybe i'll try mine with no res... so in that case it must be a power supply problem or code. is this a switching supply? edit* i'm assuming you tried both singly.  how are you connecting the pair?
  2. Help with LED matrix

    yes you need the resisters but they do need to be lower in value because the darlington has a fairly high voltage drop, so you only have somewhere near ~3.5 V instead of 5v (iirc). it may well be that if your leds are not efficient enough you will need better leds or source supplies for each source pin as well (udnxxxx whatever it was).  each pin of the 595 can easily supply 25mA or so for a high power led, but the total power with all 8 on at once is too high for the power rating of the 595. i planned on ~12mA max per pin.  if you have the datasheet for your leds, you can calc r as:     R = (5 - Vuln - Vled) / Iled where:     Iled is target current in Ampere     Vled is the voltage drop of the led at Iled     Vuln is the voltage drop of the ulnxxxx (this needs to be adjusted a bit if the timing characteristics of the leds cause them to dim when pulsed) i made some guestimates to arrive at 150r (since i got my leds surplus), which does seem a bit dim thru the sparkfun buttons.
  3. Help with LED matrix

    where are your current limiting resistors?
  4. New Controller from Wacom

    woohoo! now i can lay down the dope moves, and build my campsite cred.
  5. Vote Earth 2009

    ahhh that's more like it. now: bigger carbon footprint, orgo or ftumch?
  6. Vote Earth 2009

    hehe "break down" was more hoping for debate on the young ones, or anarchy, or cliff richard...
  7. Vote Earth 2009

    lol, watch out or rick will hold his breath...
  8. Vote Earth 2009

    or we can ban all cars in case there's a cliff
  9. New Controller from Wacom

    mmmmm dj hero for xbox360...
  10. Vote Earth 2009

    lol: new "scientist" is "new science" like "new economy"? both built on consensus...
  11. Vote Earth 2009

    i'm still afraid of global cooling since the 70s, so i'm leaving all my appliances on all the time!
  12. Slide pots in a sidbox?

    hehe, you should call it "marvin" then you can say "hey, marvin, since you have a brain the size of a planet, could you just send this pot position over there? thanks"
  13. sorry, just catching up... i think a more likely (or just another) reason you need lower R  is that the darlingtons have a fairly large voltage drop...
  14. mmmm led pr0n mmmm flax oil...
  15. toneburst Builds An MB-6582

    buncha fargin liberals!
  16. ok, i think we might have had a misunderstanding here. seeing your schematic would help, and you don't need to worry about copyright, but should post it here, not on an external site... but i think i get where you are going: with only single color leds, you could get away with connecting left and right rows both to the same DEFAULT_SRM_DOUT_CATHODES1 pin.  i thought you were planning to connect switches and sink transistors to the same pin...
  17. MIDIbox SEQ V4 Teaser

    woohoo! i better get that core32 finished...
  18. no this is not true. with sink drivers the pins have to be inverted (using the mask you mentioned) thus the button rows are high while the led rows are low and vis versa...
  19. you might have a ground loop with your computer via the midi device... but this would be a problem regardless of what app is uploaded.  it could still be hardware if the serial outs try to draw too much only when an app uses them...
  20. this sounds like hardware problem, maybe your supply is acting up only when you draw more power.  try starting with a core and lcd only, with nothing else connected, if that works add one thing, etc 
  21. Another crazy DMX project

    hehe some important details there... a box will help for sure, but you'll want a hole to let the hydrogen out.  this only happens while charging so you could charge it and then install it... i'd still use a box though, i've only seen two car batteries explode this way, but that was enough to scare me.  since it can happen, it's good to take reasonable precaution... re: thick cables, it seems you'll want those for 220v anyways... i have an led flashlight that throws a beam several blocks, brighter than any of my regular ones... maybe consider getting some of those in bulk and replace the switches with relays or likesuchas...
  22. thems the ones.  no need for both.  he sells pcbs separately as well as with kits.  using both footprints allows user a choice.
  23. yes, exactly as indicated on the c64 optimized diagram