I am very new to electronics: I've put together most of the projects that came with the beginner's kit I ordered from SparkFun and have been enjoying it a lot. I am, however, constantly frustrated by the large gaps in my knowledge.
I have a single, flexible IKEA LED dioder strip (http://www.ikea.com/us/en/catalog/products/60192355/) that I bought before I had any greater ambition. I know it's far too expensive, but, hey, I already have it. I'm trying to figure out the simplest way to start controlling it with my Arduino Uno.
I have a 12V barrel jack power supply plugged into my Arduino. By connecting a wire to Vin (voltage in, I'm guessing?) and a wire to ground, I've been able to figure out which of the four bundled wires that lead to my dioder is for power and red, green, and blue, respectively. (I essentially followed the instructions here: http://www.instructables.com/id/Control-Ikea-Dioder-LED-Strip-with-Arduino-16X-P/step2/Decode-DIODER-wires/.)
When I connect the RGB wires to pins 9, 10, and 11 on my arduino, they do light, but they won't go very dim at all. I can't seem to get them to go from all the way dark (0) to all the way lit (255). I have a few questions:
1) Is it legitimate to attempt to duplicate the super-simple single RGB LED setup this way with a powered light strip? Is my attempt to control brightness being foiled because of the difference in how the strip is being powered?
2) If there's a problem with this setup, what would be the simplest way to go about this? Do I need the ULN2003 I see mentioned elsewhere (http://arduino.cc/forum/index.php/topic,22202.0.html)? If so, what is its purpose? It seems so self-evident that nowhere in the discussions about it do I find anyone mentioning its role. Is the ULN2003 similar to the 74HC595 shift register that came with my kit?
3) Is there anything dangerous about my current setup? Am I risking burning out any of my components by flailing around with a 12V current like this?
I recognize that these questions must seem absurdly stupid -- I appreciate anyone's patience who's willing to try to help me venture past the absolute-beginner steps I've taken so far. Thanks in advance for any help anyone can provide.