I'm designing an interactive table that responds to objects by reflection of infrared light off the objects to a sensor below. It is made from a matrix of around 300 IR LED and sensor pairs, with each pair located at the bottom of a 2 x 2 x 2 inch well. Each sensor can only see the LED when a hand or other object is nearby to reflect the IR light. I want the the sensor's output to give a detection level between 0 and 100% of a nearby object - so I imagine that means it has to be analogue giving say 0 to 5 V on an output. I also don't want other sources of light to interfere with the sensors so I think using modulated (say 38kHz) IR LED and sensor pairs is key. Lastly, because I need so many I would like them to be cost efficient.
Given those criteria can anyone recommend the most suitable IR LEDs and sensors? I've seen a few but some give a digital 1 or 0 only output I think (?) and others aren't modulated. So I was hoping someone could recommend the best options, thanks!
For clarity - it will be something like this: https://www.youtube.com/watch?v=vzWEgOt3xsM