Just wondering if anyone had dabbled with infra red sensors?

I'm looking to have a sensor which ultimately provides a DC voltage (representing how close the hand is placed to the sensor) that I can AtoD to extract the DC level/magnitude.

i don't want to use ultrasound as I'm toying with putting this on a guitar (& I'm worried about how wild string harmonics might interfere with an ultra sound sensor pickup - I remember jangling car keys & being able to change TV channels with an old TV that used ultra sound!)

But wrt using infra red...I'm thinking that it might be difficult to get a decent hand control 'range' going on - I'd like the 'range' to be about 8" (20cm) from the sensor.

Has anyone dabbled?