I'm trying to use the IR source and detector of the CD Pickup reader/writer (KSS-213C) along with the lens focussing/tracking system. I want to control them using an Arduino MEGA. So since I will be needing one constant source for the diode, I will connect it separately to a source, not to the Arduino. Since this is a sensitive device, I read that you need to have constant current sources and so on. Now, I'm new to designing circuits of my own, I found this picture in an article, but it is for a DVD writer. Could someone tell me if I could use the same circuit with some modifications or should I try something else. Now note that my main output is that of the IR sensor that my Arduino would read.