120 LEDs

hi folks,

this is a more general question...

I need to control 120 LED using an arduino. At some point i need all 120 LEDs lit up at once or blinking so fast that it would seem they are all lit up.

So i wonder: is it even possible? what additional hardware do i need? what about the power supply?

best regards Roderic

Here is a project that controls 125 LEDs in a cube configuration. The external components used could apply to any project requiring a lot of LEDs to be controlled in a multiplexed manner using external serial shift registers.

http://picprojects.org.uk/projects/lc/index.htm

Lefty

That was quick! thank you very much!

You could also consider using the MAX 6954, that allows up to 128 LEDs to be controlled and there is a degree of dimming available in blocks of 16. It's all done in hardware so there is minimum software load on the arduino.

thanks for the tip but the MAX 6954 seams a little expensive (i am from germany... i don't know how much they cost elsewhere). On the other side: if it makes things easy its worth the money.

i just read something about a thing called multiplexing and shift register... is this a way to tackle my problem? it seams possible but complex to code.

i am just collecting ideas here...

i think i found what i was looking for: charlieplexing :slight_smile:

looks like a good start for me as i am new to this kind of things…

[edit] well, maybe not

“Complexity
Charlieplex matrices are significantly more complicated, both in the required PC Board layout and microcontroller programming, than are traditional multiplex matrices. This increases design time.” wikipedia on charlieplexing

You could use 4 M5451 constant current driver chips 35 outputs each...

Used on the CC-Shield and lightuino http://effluviaofascatteredmind.blogspot.com/2009/10/lightuino-design-thoughts.html

Mowcius