driving lots of leds

softcon

What kind of setup would I need to drive several leds (such as to spell merry christmas or happy hanukkah, or something similar) I habe both a basic stamp, and (hopefully shortly) another propeller quickstart board, so either one is fine for the project, but how would such a thing be powered, and how would I hook so many leds together? I'm not (yet) experienced with electronics things, so this is new to me, but if I can get this to work, I plan to do this sort of thing a lot.

Martin_H

Perhaps my LED Marquee will fit the bill?

http://forums.parallax.com/showthread.php?136152-LED-Marquee-Module-for-Gadget-Gangster-Platform-(w-video)

tonyp12

How do you want to interact with them?
Full control to turn each every one on/off on demmand.
or In groups of 1/4 is good enough control.
You could put all of them in series if you give it 50v dc, there are boost led drivers that do that.

softcon

I was thinking to control each led individually, but I definitely see the draw of having a prebuilt font. I couldn't build the strip mentioned in the post though (I can't solder, since I can't see) but it would be interesting to build something similar. I'd thought to just get a large (maybe pc motherboard sized) blank protoboard, and move leds around as necessary to draw each letter, then light them all up at once, perhaps alternating letters or something similar, still only vague ideas here, have to do what works for me, which due to lack of soldering capabilities means not much. Thanks for the suggestions, will keep looking, maybe the 50V idea will work out a bit better, but don't know until I see something like it.

tonyp12

If you're legally blind, I don't know even if DIP IC are large enough but here is a list of LED drivers in that format
http://www.mouser.com/Optoelectronics/Drivers/LED-Drivers/_/N-7zi53Zscv7?P=1z0y3waZ1z0z44dZ1yzt5xtZ1z0y33vZ1yzspjfZ1z0y33rZ1yzt66nZ1z0yrrjZ1z0z7v3&Keyword=led+driver&Ns=Pricing%7c0&FS=True

This one looks interesting as you can put led strings up to 36v (red/green leds = 14-16 of them, use 36 / leds rated-forward-votage to get correct number round it down)
and have 16 groups = 256 leds to spell words.
http://www.mouser.com/ProductDetail/Maxim-Integrated-Products/MAX6971ANG+/?qs=sGAEpiMZZMtnFuLo2AlFPjH%252bt7M40yMssOYE%252bufDlLI%3d

Martin_H

The inability to solder will be a bit of a barrier, but there are 8x8 pre-built led matrices which have the control pins along the side and top. They cost about $10 or so mail order. You might be able to drop the top pins into a proto-board and run jumpers using alligator clips from the side pins to the proto-board. Put a microcontroller in the middle of the board with the current limiting resistors and wire jumpers to the 8x8 matrix. Since the matrix will be small almost any microcontroller could drive it.

erco

Much easier to just light long strings of LEDs. Use a higher-voltage supply like 12-24 volts so you can connect 10 or so LEDs in series with just one resistor. Saves time and energy. You experimentally determine the right resistor value for each string based on the LED voltage and number of LEDs. That's how we made this: http://www.youtube.com/watch?v=LvuZd0b9e_g