If you have the ability to make your own PCBs you may also want the PCB design, in EasyTrax format. The PCB is small enough to be mounted within a DB25 header, and that's how I have my current device. It looks pretty sharp!

If instead you choose to build the CIR using point-to-point soldering, I suggest using a 1" sq. copper ring board, and making sure to cross out each connection on the schematic when made with the soldeing iron.

Components are not too critical, almost any NPN transistor and any small signal diode will work fine. But get a good IR LED and phototransistor! The tiny things Radio Shack sells in pairs are worthless. (They look like little matcheads, and I had little to no success using them.) Make sure you are getting a phototransistor, NOT a photodiode!

I cannot stress the importance of observing the diode and transistor orientations enough. Please double-check their orientation before soldering them in place, if they're in backwards the circuit will not work.