Uwe is correct about the Apple remote. I did test it thoroughly. (I have about 100 of them and it would have been nice to use them instead of building pens.) They worked well when I tested on a 17” LCD monitor. But when I moved the test to a real whiteboard with a projector, the Wiimote did not “pick up” the remote nearly as well as the pen that I built with the LED’s that Johnny suggested. Even my crude pen - LED soldered to a switch soldered to a Radio Shack batter holder (AA) held together with electricians tape - worked far better than the Apple remote.
I have since made a pen out of the dry erase marker housing. It works much, much better.
I have it in a 5th grade class now being tested by one of our teachers.