LED Board Powered by a PI?

[benhamin13]

Hey! I was wondering about making a sign made out of LED's that was powered by the raspberry pi, something like the Pi Lite but bigger and (and with buttons so you depending on the button pressed it would show a different) so it would be seen at a concert! But, this is where it get hard well for me it does (I am only 15!) how would i go about making something like this? and what would i need to make this? because i have the pi lite and i have got the pi lite working how i want it to, all i need to do now is make or something find something like the pi lite on a bigger scale because i can program it ish but i dont know how to go about making something like that or what i would need.

If you have any ideas or any tips please can you comment below! I hope you are help to help me!

I am planning to use this when I go to see Taylor Swift in concert in june 2015, so i want to make it big enough so it is able to be seen!!

Thanks for reading this!!

[Ravenous]

Here's a really big example I remember seeing a while ago (several boards stacked together):
http://www.raspberrypi.org/forums/viewt ... 62&t=85603

Security might not let you in with something that size though! But at least the singer won't forget the words.

[Laurens-wuyts]

With so many LED's, I think you are going to be in trouble with batteries.

Laurens

[mahjongg]

you don't "power" multiple LED's (drawing more than 15mA), you control a transistor switching them on and off.

except the control signal is only 3,3V which is too low for most FET's (the ones with wires), and transistors need a large base current so they conduct enough for a large collector current (>200mA).
remaining choices are carafe mount FETs (so called logic level FET's), or darlingtons.

If you want to create several controls, you can use 6 darlington in a DIP-14 package, these chips are called ULN2007, and are cheap and easy to use, can also be used to drive relays.