Infra-red detector

I got this kit when I was planning to build the IR light pen
for Loctor. Unfortunately, the pen in question has gone
missing. Anyway, since I cannot find a nice project box
to house the circuit board and the battery, I just used
some double-sided tape. And I was so happy the kit
can take 3 volts instead of the recommended 9 volts.This
is a very useful tool as I do not want to use the Nikon D50
to take pictures of the Infra-Red LED (as you cannot see IR
light with the naked eye, even if you dress it up with contact
lens.) when I test it all the time. What I do is to use the LED
tester and then when the LED in the kit lights up, this means
the IR LED is working. Not bad, eh?