Dot detector help

[Marc Bergmueller]

Hi, I'm Marc and I've been out of electronics projects for 20 some years and have forgotten much. I'm looking for a simple,fast acting circuit that will detect a black dot on a white piece of paper as the the paper is passed under the detector. The detector will actuate a solenoid to tap on a snare drum and must work under low light conditions. Thanks for any help.

[Marc Bergmueller]

Anyone?

[I_Daniel]

Insufficient information.
On what is the black dot ? What causes it to pass over the detector ?
Why a black dot and not a simple light activated switch. i.e a detector closely couple to the trigger (LED) which can be used in bright light or total darkness ?
A solenoid is slow so why the need of a fast acting circuit. A light activated switch is much faster.
Why can't a simple on/off switch be used to bring in the snare drum ? How long is the snare drum required to be on ? One beat or continuous ? Why not a foot-pedal for the snare drum. etc. etc. etc.

Sorry I can't really help these are just some questions that come to mind.

[I_Daniel]

Okay your second post said "Anyone"

So could you give me some answers to my questions ?
I never say I can help but if I can I do.

[Marc Bergmueller]

I want to add a snare drum track to a crank organ. The crank organ uses a paper roll with holes in it to make sound. Most people use a solenoid to strike the snare drum. Each dot would represent one note.

[I_Daniel]

If the black dot blocks out any light while the rest of the drum lets i through then you could use something like a day/night switch that you find one some automatic lights on switches when it gets dark. Say for instance use a LED on one side of the paper and a detector on the other side.

Sorry I can only point you in a direction.