Alright, I've got a 2'x2' square "tub" with a couple inches of water in it. I'm looking for a way to detect when and where an object (such as a person's finger) penetrates the surface of the water.
So far I've thought of an array of infrared beams positioned on two sides of the tub with detectors on the other two sides (example below). The whole system would be slightly above the water. Each beam/detector combination is spaced approximately a centimeter apart so that it's near impossible to put something in between them. At this point it becomes a simple matter to determine the position from the broken beams.
Now first, is there a cheap infrared LED that is able to throw a focused beam of light 2-3 feet, or would I need to move to something like an IR laser (which from what I can tell, making an array of them would be cost prohibitive). Perhaps even a packaged array set up already?
Second, is there simply a better way to go about doing the whole thing?
Now this the first time I've ventured into anything like this, so any and all reccommendations or ideas would be great to hear.
So far I've thought of an array of infrared beams positioned on two sides of the tub with detectors on the other two sides (example below). The whole system would be slightly above the water. Each beam/detector combination is spaced approximately a centimeter apart so that it's near impossible to put something in between them. At this point it becomes a simple matter to determine the position from the broken beams.
Now first, is there a cheap infrared LED that is able to throw a focused beam of light 2-3 feet, or would I need to move to something like an IR laser (which from what I can tell, making an array of them would be cost prohibitive). Perhaps even a packaged array set up already?
Second, is there simply a better way to go about doing the whole thing?
Now this the first time I've ventured into anything like this, so any and all reccommendations or ideas would be great to hear.