LED light set up

[alexp90]

Not sure we're to post this and after trawling site and google haven't found an answer

I want to make LED circuit to light up my case. It will be made up of 4 (possibly 5 but work off 4 for now) sets of 4 LEDs all rated at 2.2v and 20ma
If they were set up as follows

IE each set of 4 would be in parallel within a parallel circuit, if that makes any sense :S
I'm trying to work out the volts and amps that would be running through it as i'm trying to run it off the PSU, either 5v or 12v
Would i be correct in thinking the volts would be 2.2v and there would be 0.32A in the loop?
I know i'd need a resistor so how do i work out what ohm? :S

All help appriciated!
Alex

 

[alexp90]

im looking on ultraleds. Planning to get all the same colour (at the moment red but once i work out how to do the calculations on red it may change)

specs given

6,000 Mcd
Red 630 - 640 nm
20 ma
1.8 - 2.2 Volts

The drawing is a simple version of what i was planning. The 'main' wire you see would plug into PSU and then the 4 sets would separately plug into that, wouldn't all be soldered together (so i can manage the wires within the case)
I was thinking of doing the sets in series as suggested, do you think thats the best choice?
Thanks for the help so far (thanks for the link death). I'll keep working on it but i'll probably be back with a question!

Edit: Already Back! Can someone explain how they got 180ohms? I'm trying to work off my limited knowledge of my AS physics, not going well, i'm getting 160 but know im going wrong somewhere.
Edit 2: Ah! is it because 160ohm resistors aren't realy sold?

Alex

 

[alexp90]

Ok thanks so far, after taking on board comments i have come up with another plan, Similar to the last but the sets are in series and its now got the resistors in. The resistors will be 180ohms. Does that look like it will work ok?
Also if i was to add another set of 4 in as the rest it would be the same wouldn't it? 180ohm resistor in the loop and just add to the parallel 'main'

Hypothetically could i add as many sets of 4 in as i wanted like this? (within reason of course, staying within the PSUs current limits)

Thanks
Alex

 

[alexp90]

Brilliant! Thanks for all the help, Will be a while before its all done as i havn't even started choping the case they will be in up yet. But will put some pics in a build log. Hopefully will be getting started on saturday if i have the time