We’re actually planning on using it as an optical encoder for our shooter. I asked specifically about a banner replacement, because it’s a very versatile sensor and I have been looking for a good replacement since they stopped putting in the kit of parts.
If you want to see if some thing is in front of a sensor with no contact(limit switch replacement), These worked well for us this year to detect where the balls were in our bot. http://www.pololu.com/catalog/product/1134
A couple of things to know about their use. Direct natural sun light and some florescent lighting can cause problems. Best used in the robot with some light shielding. We had problems with the digital side car 5 volt power supply. We added 100uf to the side car bus and 22uf at the sensor. The motion of the object should be perpendicular to the sensor. Once we addressed these issues, they worked very well for our ball racking system. The other Sharp analog distance sensors also have worked well for us with the power fix. Not for the shooter velocity. There are several threads on the velocity and encoders.
It’s not terribly difficult to set up a 12V supply line. We just take one of the screw terminal sets from the KoP and bring a power line from the PDB to it and use that to feed power to the sensors. We have a similar setup for our signal and ground lines, so it provides very little hassle to set up.
If you want a cheap optical encoder, 1023 used this encoder and pigtail with success.