hi there!
just wanted to show you my pen.
for the pen i used an old deco-marker. unfortunately, there was still a lot of fluid in it. be careful when you open those markers...my table is now a bit silver
i used nail laquer remover to get the inside of the marker free from the fluid.
my led is a 100mA, 940nm IR-LED (for all austrians: i got it from conrad)
my power source is a 1.5V AAA-battery, directly connected to the IR. if you use just one battery, you don't need any resistor.
between the battery and the led i soldered a momentary switch. the red knob is from an old laser-pointer.
i needed about 3 hours. but i think you can be a lot faster....most of the time i spend cleaning the damned pen and my desk.
cheers,
Chris
