For object detection you don't really need to send any data. Just turn ON the carrier, pause for a minimum of 10 cycles (or whatever time the data sheet indicates as minimum burst period), sample the detector output, and turn the carrier back OFF.
Don't turn the carrier on and leave it on. The detector will assume the continuous carrier signal is noise, and ignore it.
The TSOP brand is much better than the Panasonic, but they will both fail if you leave the carrier on for long periods, or if you do not provide a carrier burst long enough to meet the minimum burst period.
Look at the TSOP17xx data sheet in the Suitable Data Format section.
Turn the carrier on for a minimum of 10 cycles per burst, sample the detector output, then turn the carrier off.
These types of IR modules are designed to ignore carrier bursts that are too short, and continuous bursts. It assumes these signals are noise.
Also, it's important that you're using an IR LED matched for the detector. For the PNA4602M & TSOP1738 you'll want an IR LED with a wavelength of ~940nm. This is the peak spectral sensitivity region of these detectors. Using one that's way off the wavelength of your detector, you will definitely see odd results. If it works at all.
For object detection where the LED is located in close proximity to the detector, use a large value series resistor, and cover the LED with heat shrink or some material the blocks side emissions from the LED to detector. That will help.
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