Hello!
I'd like to use the spare parts (phototransistor, IR) of the interactive led panel to light an LED. I'd like to make something simple, just light the LED when there's movement, and then turn off again, no "animations"(pulsing, etc). Do I *always* have to use an IC for that ? I'd like to make it without ICs or microcontrollers, if possible.

You could use our dark detecting circuit as a jumping off point:
http://www.evilmadscientist.com/article.php/darkpumpkin