I am trying to setup a rig for water drop photography. This is where you take a picture as a water drop is impacting against another object or body of water. The trick is to detect the drop as it falls and then use a tuned time delay.
I want to detect when a drop of water interrupts a light source as it falls. The most important factor is that it be repeatable. I need it to respond to the interruption consistently. The sensor also needs to be fairly quick as the drop only interrupts the light very briefly.
I have seen photo resistors, photo transistors, and even photo diodes. Which of these or other parts would be best for my use?
What sort of light is best? Should I use a laser or IR or something else? Water is clear in normal light which could be problematic, is it clear in all spectrums?
How do I deal with ambient light? I have heard that by pulsing the light source at a known frequency it can be differentiated from surrounding light.
I am basing the project on an ATMEGA328 but am happy to add other parts to work with different sensors. I am also interested if anyone has a solution other than light based sensors.