PWM, mosfet and LED strip

Hey.

So i bought 3 IRL530NPBF and a Arduino Uno, and I´ve got 4,3m LED strip. There is resistors built in the led strip so i dont need any resistors to the strip, just 12v.

So I´ve tried connecting the LED strip´s GND to the drain and GND to source, and the arduino to the gate, as I was told. But nothing happens.. What am i doing wrong?

GND to the drain and GND to source

Tell me more.

The LED strip got on wire to 12v and RGB is GND, so i connect the 12v to the powersupply and the RGB to the mosfets

Dunno about anyone else, but I can not follow your verbal description of how you are connecting things? Draw a circuit diagram showing what is connected where. Include everything, even the power supply.

Here is the diagram ..

If we assume that you have the pins on the FET connected properly (they are not identified in your circuit diagram), then the most glaring problem is that there is no connection between the Arduino GND and the GND on the ATX power supply.

Assuming, also, that when you connect the ATX power supply directly to the LED strip, it lights as expected.

The first pin on the FET is gate, the middel is drain, and the last is source. That´s what my datasheet says.

The strip works if I connect it directly to the ATX powersupply.

So I just have to connect the GND from the Uno to the ATX?

I can guarantee that it will never work WITHOUT that connection.
There is an excellent chance that it will work WITH that connection. But there could be other issues we haven’t discovered yet.

Is it just any of the GND from the Uno or is a specific one?

It have to look like this?

Oh thanks, now it works!.. I was wondering, can I connect the 5v from the ATX to the Uno ?..

If it is really 5V. Some computer power supplies don't behave well without a significant load (like a PC motherboard with CPU). I would measure it before assuming it is really 5V.

It is, just measured it and it´s okay, also tried it on the Uno. Thanks man!

All the grounds on all Arduino boards are connected together and considered to be equal.

Wasn't it you Americans who said:-

"We hold these truths to be self evident - all grounds were created equal"