IR rain drop sensor

Hello this is my first post.
Is something like this possible to create?
Can IR receiver detect water drop in flight and activate arduino interrupt?
Or I must to use concentrate laser beam instend of IR led?

Do you think that the light path shown in red, is the only path for light coming from the LED? For example, the first diagram shows 9 reflections. Isn't there another different path with 11 and so on? Also, with so many reflections, you would need front surface mirrors to avoid glass diffractions.

You're right.
Will measuring the resistance of the photo receiver give different values and could the analog read measure such values, or would I have to detect a change in light intensity through some additional integrated circuit.
Not all rays path have to be interrupted, if only 50% of the rays path interrupt, would that be enough for analog measurements?
Or is it best to abandon this idea altogether?
Thanks for your reply.

I like this idea, but I agree that - because there are effectively an infinite number of paths between sender and receiver - raindrops will not produce a reliable signal.

I think a laser-based system would be better. You could make the "fan" really tight - dozens of reflections - so no raindrop could pass through undetected.

Another approach would be to make a "fan" of light, and instead of looking for blocking objects, detect the reflected light from objects passing through.

Reflected light probably will be too little to easily detect. Distance between mirrors need to be at least 7 Cm, for rear rain drops to catch.
Your right, laser will be better solution.

If they are ionized, you could detect them by passing them between plates and reading the voltage.

I have trade with one idea early.
Put microphone in sealed plastic box with flat tightened lid and tray to detect sound. Sound when drop touch lid is loud, I can hear them, but with this microphone I can't have good result.
Analog meserment on "A0" of arduino uno, in olmost empty "void loop" cant detect drop every time, probably becos signal from microphoce is to short (in milisecond) for arduino to detect.
Digital output from microphon cant adjust for precise detect.
Have someone some idea to inprove this method?

piezo disk contact microphone.

Sorry aarg, I do not understand your answer.
Do you suggest to solder piezo instead of this microphone on board?

That is the device, I actually presented it as a general solution, many projects have used them as impact sensors, in all different ways. You could search them out and choose a method of interfacing that might work for you. You can connect them directly to an Arduino input with only a few additional components, e.g. resistors.

Instead of continuous analog sampling, you could detect by means of the threshold on a digital pin. Possibly, if you know what you're doing with them, with an input interrupt.

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