I've been working on an Infrared sensor to allow my rc car to detect obstacles and move to avoid them. I have had success using a design I found here at ikalogic.com, it's quite a complex design but it works well when completed.
I used a 555 timer chip to pulse my emitter LED on and off however I did not encounter the difficulty with over heating which is discussed in the article on ikalogic.com, my circuit seemed to have no problem running without the timer. I do not suggest you ignore it, I may have supplied less currant than they did so best to include it.
You can see a small video of the prototype being tested below. It used an Infrared transducer as a receiver and the result is a beam which detects objects around 25cm away.
Following this success I moved on to produce a board to use in the RC car. It is mostly based on the design from ikalogic however it uses a chip to control the timing of the IR sender. I found that the system did not seem to work consistently so I replaced the IR transducers with normal IR LEDs and this resolved the issue but reduced the signal distance to around 10cm. With this board I was able to do testing, I dismantled a second RC car to get a board which can send the signal from the RC car back to the computer. I connected these boards to my RC car and found that my signals interfered with each other, I then had to locate a third RC car to use as the base.