The reason I mentioned the 556 is because I see a lot of datasheets for IR receiver ICs that have indicated that there need to be pauses in between bursts of the IR signal. I am currently using a 555 to generate the 38 kHz. In total, it seems that I would need one timer to create the correct IR frequency, one timer to pulse the frequency, and one timer to create spaces between the series of pulses.
This is for a robot I am trying to build. I would like to bounce an IR signal off of an object about 1 foot away to detect obstacles. I have seen examples of such circuits in books and on-line, one of which used an IR receicer IC (PNA6402M). However, it is unclear as to whether or not I need to transmit the 38 kHz IR signal in bursts to activate this receiver, or if it will detect a continuous signal. Nothing too spectacular, but, like I said, I am still new to electronics - so whenever I get anything to work, I am very pleased with myself!