What the circuit does is very simple: once the PIR motion sensor detects a motion, the OUT pin is high (3.3v) and it will put the MOSFET in an open state. The LED strip will be therefore on.
It's working like a charm but I think I'm missing some components to make a more robust circuit.
Some information about the voltage source: it's a 220v AC to 12v (adjustable) DC converter. It seems that the LED strip is slightly blinking from time to time. I don't know if it's because of the converter or the MOSFET.
Any help for a newbie will be appreciated.