I need some help. I built a simple circuit that allows me to adjust the brightness of some IKEA LED Lights. You can see a demo below:
The LED’s require 12v of power to turn on. Since the Arduino didn’t have enough power to power them directly I built a simple circuit using transistors.
The Arduino is also powered from the LED’s power source (12v). So normally, when I unplug the LED’s then the Arduino turns off. However, when I have the Arduino plugged in using USB, then the Arduino keeps running even though the LED’s are off.
What I would like to know if when the Arduino is powered from the External Power Supply or from USB. I am sure this can somehow be done. However, I have no idea where to start…
I am a software guy, not a hardware guy :).
Any help is welcome.