Nice LED. I might have to get a couple!I'm certainly impressed with it. Might be tempted to try this http://www.ebay.co.uk/itm/30W-30-Watt-High-Power-RGB-Full-Color-Rainbow-LED-Light-DIY-/230767996419?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item35bad82e03 next time.One thing...do the MOSFETS/resistors in the power supply get very hot?Red MOSFET gets warm enough for a heatsink due to greater voltage drop but blue and green hardly get warm at all though I have put heatsinks on all of them as the electronics are in a plastic box with little air flow and will be on for hours at a time.2W seems a little on the low side for the resistors. I'm thinking the resistors in the photos are more than 2W.Without ordering online and paying P&P I could not get a small 2W 2.2ohm resistor so got the 3W wirewound ones from Maplin
What is the difference between the circuit you linked and this one?: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/Apart from using different MOSFET and resistor values the circuits are the same, the schematic I attached to the first post has 3x of these circuits to separately drive the RGB colours in the LED it also has a voltage regulator to give a 5V supply for the ATtiny85 that does the PWM colour changes.Yours has extra parts for beeing PWM friendly as it says on the page, but I really don't understand the explanation.I did mine and I noticed that when PWM level is low the led blinks a little, I really don't know if it will bother with the other colors turned on, need to test that.I use no extra parts to make the thing more "PWM friendly". I don't notice any flicker at low levels but that might be because at lease one other colour is always bright so may mask the flicker effect.Do you think adding those extra parts will solve that?See above
Apart from using different MOSFET and resistor values the circuits are the same
How should I change your .ino script if I need this on Arduino?I have all the components of ATtiny-RGB Moodlamp.pdf but instead of Tiny I have Arduino.
Thanks a lot for your shared project. Can I use irf540 instead of irf520? Is it risky to test irf540?
I tested this on Arduino. There are two things that are not ok. It works but the led is cold and not bright as it can be (I have http://www.ebay.com/itm/1pc-10W-10-watt-rgb-High-Power-LED-Light-Lamp-Chip-Lamp-Light-/131112967487?pt=LH_DefaultDomain_0&hash=item1e86f11d3f ). If you use different LED, MOSFET & transistor values then you may need to calculate different resistor values for R2, R4 & R6.See this article and the component data sheets to work out the correct resistance and wattage values needed.Secondly, colors are switching that means not fading.Should I use 0,1,4 PWM pins on Arduino? Any comments what should I change?You need to use PWM compatible pins. On the UNO they are pins 3,5,6,9,10 & 11 (the pin number on the board has a ~ in front of PWM pin numbers)