Motion activated RGB-LED-Strip

I changed my 12V Supply to a higher quality one, now everything works as expected.

I think the problem was, in sleep mode the circuit draws so little current, that the supply can't hold a steady voltage.

The only small problem left is, at low brightness you can see the individual brightness levels.
In the future I may add 10/12? bit software-PWM to get smoother dimming of the LEDs.

I haven't fixed the power supply issue yet, but I finished the control box.

The box features a momentary button, a green LED (with resistor) and a toggle switch, which switches the 230V for the 12V supply.

Next week, when I am back in my apartment, I hopefully will figure out what causes the power supply issues.

Everything works as expected if I power the circuit via the ISP programmer (Arduino UNO) or my bench power supply.

But if I use the 3,3V regulator from the PIR-module, the circuit behaves strange. I also tried a L78L33AC regulator powered from the 12V rail, resulting in the same strange behaviour.

My circuit consumes less than 10mA, which both regulators should be capable of.

I uploaded the code to Github. The code is almost finished, but still needs some tweaks.

I also added the schematic to the files section.