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Made it by myself, I guess not the best one.
It's an understatement because it will simply not work 
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Oh, okay this I didn't know. So the point of the driver is ... not sure.. ?
Like I said, a led ALWAYS needs a current source. For small leds connected to a fixed voltage a resistor will do but it's a terrible current source for high power leds. Using a off the shelf switch mode led driver is
- Cheap
- easy to use
- energy efficient
- so no need for huge heat sinks
You could also make a linear current source with transistors which is a lot better then a resistor (who wants a 7W resistor) but that transistor will still produce A LOT of heat.
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Good to know ! Thanks
Whaaaa, now I see my quote again I see a terrible typo! Edited the post and here it's correct again:
septillion:
A 10mA led (with limiting resistor!) connected to a 10A supply will still just draw 10mA as long as the voltage is right.
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Hmm, not sure what's switch mode led driver? Something that doesn't use resistors? I need to find out, haven't heard of that. Everything I've read about leds and changing their color includes 1 or more resistors 
It's a little module. Some links:
PT4115 900mA
PT4115, probably 600mA, not 100% sure, listing is a bit weird
Probably PT4115, 300mA
Which you need depends on the LED you have. These are just some example I found quickly so looking further may not hurt. I think all these three are based on the PT4115 chip which is a very popular chip. Although most modules don't break the pin out (aka, don't add a solder pad) the chip does support dimming via PWM. Just solder a wire directly to the chip and it's a very easy driver. Only downside, it switches the low side and measures the high side. Which means you can't control leds which have a common connection. (No common anode, no common cathode.) You need RGB leds which have 6 connections, an anode for each color and a cathode for each color. There are other chips/modules that don't need that but you'll have to look for them.
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I also purchased this, not sure what it is but it has led in the name
2PCS MAX7221CNG MAX7221 MAXIM DRVR DSPLY LED 8DIG 24-DIP NEW GOOD QUALITY | eBay
The MAX7221 (or the more common MAX7219) is a cool chip to multiplex leds. Nice if you want to control a display. Not really for dimming.And it can only driver max 100mA @ max 5V.
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Oh, you can limit it in other ways, I didn't know this. I thought you'd need an X ohm resistor and after that you can (ex. with potentiometer) change the strength.
Like I said, you need a current source. And a resistor form a very crude form of a current source. Perfectly fine for normal leds (if you have a stable voltage) but not the only option. And for a high power led a resistor (or I would even say any linear driver) is a pore choice.
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12v --> potentiometer [or arduino] --> resistor --> led --> ground
and the resistor should be so, that the led gets it's required current, and after that you can dim with the potentiometer or other
A pot to directly control the brightness might work for a single small led but anything more will be to much for a normal pot. A pot has a power rating as well. And for standard pot's it's not much.
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I'll add all the parts I think are needed for the project/s in the end of this post
Thanks but can you next time place them in url tags and give them a name? (like [url=url-here.com]a name[/url]) That way I can see what you linked right away.
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Pretty much everything else but C++ but I think I can get on it pretty quickly. And about memory usage, I have always been quite nifty and exact with what I use But lets see how everything turns out!
Nifty and exact is good. Because C/C++ is pretty precise (unlike PHP for example) and memory is "low". More then enough for most tasks though. Otherwise they won't have made it.
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So I can't run my output of 555 to mosfet? Which would turn the mosfets gate (or something) on / off?
Yes you can, but with a simple astable 555 that will give you dimming, not fading.
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I thought I could change the duty cycle of astable mode of 555 which would result in some kind of fade. Not sure how to make the change of the duty cycle though.
And that's where it gets complex is you want to do it with discrete components. 555 and a pot which you fade is easy. Making it fade on it's own, without the pot, that's the challenge. Not impossible, not super duper hard. But if you're thinking about using an Arduino anyway I would say this is the time to let the (super duper cool) 555 go.
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Links:
First isn't available anymore 
The mosfets are not logic level so limited switching capacity if you use them at logic levels (aka with an Arduino).
The high power led has 6 pins so you can use those modules I linked. 1 per color and you can link 2 or 3 leds in series. The listing shows max 700mA so a 600mA driver is the one you want (600mA is more common).
The led strip, it says 300led/5m which makes just 60led/m. You'll have to count to check. I never worked with 3528 RGB strips, the 5050 strips are way brighter, mix way better (because each led is RGB) and not that much more expensive. Uses a lot more current though! (1,2A per meter)
