Powering Arduino Duemilanove directly from 12V source

[system]

Hi everyone,

I'm doing a project (referred in another post) which controls an RGB LED strip using BDX53C transistors to drive the current coming from the power source.

Now, what I planned was dividing the power coming from the 12VDC wall charger to power the LED strip, as well as the Arduino. Seeing as it is a 12V signal, the Arduino should be fine... right?

I mean, the current drawn by the strip is about 1.1Amps, and the current drawn by the Arduino goes around 100 - 130mA. I noticed that it gets a bit hot in the under pins of the female power jack, as well as the usb connector. I know that its driving a 12V charge, but should I be worried about the heat? Am I doing this wrong by connecting it directly to the 12V source?

I looked around and couldn't find any specific answer to this. The only thing I was careful was to NOT power the strip through the Vin pin of the Arduino. Saw somewhere (a couple of times, actually) that this would cause the full current to be driven though the Arduino, probably (or most definitely) damaging it.

I also looked around for a voltage regulator, like the 7805, but this seems it would complicate (and delay) this project even further.

Will this be enough? Or should I get the voltage regulator (which also might heat up anyway)?

Thanks

[Grumpy_Mike]

Yes you can power the arduino off 12V, the regulator gets hotter than if you power it off 9V.
See:-
http://www.thebox.myzen.co.uk/Tutorial/Power_Examples.html

[MarkT]

I'm worried by the phrase '12V wall charger". If its a charger for 12V batts it could be generating far more than 12V. Have you measured the output voltage on no-load?

[system]

Oh, sorry if I used the incorrect term. Its actually connected to a wall AC-DC transformer, that outputs 12V (about 11.98V on no load).

Then it should be no problem, right?

[system]

Yes, it does run warmer, but will be installed in a container with air vents and extractor fan, so it shouldn't get too hot.