LED power

So there was a cool project in MAKE http://makeprojects.com/Project/PS-2-You-LED-Sign/1069/1 that used a PS/2 to control a sign. I'm trying to make an LED sign with the same LED modules http://www.sureelectronics.net/goods.php?id=1118 but adapt it to be controlled using the Arduino Ethernet board. The software I can probably figure out, but the electronics (simple as they are) can be over my head.

Silly me thought I could just plug the +5V and ground right into the LED module and all would be well. The board shuts down so it seems that the LED module is drawing too much power from the board. The original project uses an ardweeny with a voltage regulator that runs everything. For this the plan was to plug the arduino into the ethernet and use the DC jack to power the whole thing. I figured the onboard voltage regulator would be sufficient.

Can anyone suggest a good way to power this whole thing?

Thanks

Silly me thought I could just plug the +5V and ground right into the LED module and all would be well.

You must use a resistor in series with the LED to restrict current as an Arduino can only provide 10-20 mA per pin (check the datasheet for exact numbers!)

Silly me thought I could just plug the +5V and ground right into the LED module and all would be well.

Yes you can, you must have something else wrong.

Indeed I did. The ribbon cable connections aren't mirrored exactly, so I had all of my connections opposite. I also had to make some adjustments to the library to work with the LED modules.

On a similar note, any suggestions for a power adapter that would be cheap? I think I'm going to build a couple of these. I found a 9V one on sparkfun (http://www.makershed.com/product_p/mksf3.htm). Is it right to assume that 650mA is sufficient to run the wiznet chip and 4 LED modules? I looked like each LED module took 200mA, but I think they are in series...

Anyone know of a cheaper adapter option, other than scrounging up old ones, that would work? Not that $6 is terribly expensive...

Thanks again!

Is it right to assume that 650mA is sufficient to run the wiznet chip and 4 LED modules?

No

I looked like each LED module took 200mA,

Yes

but I think they are in series.

No not a module.

So with 4 of these LED matrices at full bore (0.36A max) I’m going to need to supply 1.44A. What additional draw is going to be required by the arduino then?

30mA