A schematic would probably get more responses...
My very first origional AVR project, was an IR proximity detector. It's only good for about 2 feet, but didn't overdrive the IR LED or put pauses in the 38 kHz. I used a IR reciever module, fairly common 3 lead device used with many remote control electronics (TV, Stereo, VCR...). Anyway, mine was reflective, couple feet wasn't bad. I got the hardware side off Nigel's PIC tutorials. The software is easy, the module is normally HIGH, but drops low when it detects the carrier (38kHz), but it's not really picky about the frequency. My biggest problem was getting the Tiny13 to generate the 38kHz signal.
Anyway, I posted lots of questions in this forum while building it, been about a year ago, don't remember the title. Will search later.