How can I use a Integrated IR Receiver IC in a sensor circuit without microprocessors?
The sensor outputs a high level if it detects the proper input signal, being an IR carrier of 30..56 kHz, depending on the type you chose. Build a IR transmitter which transmits such a carrier. You don't need a microcontroller for that. (I leave it to you to solve this; I'm not going to do your homework completely! :-)) Direct the transmitter to any possible obstacles. If the receiver looks in the same direction it will pick up the reflected signal if you get close enough to the obstacle.
Success!