Chiming Clock

I am currently making a 24 hour clock that I would like to chimes at different points in the day depending on where you place markers round the edge of the clock. I already have the clock movement but I am unsure what I will need to program an Arduino, so that the markers can be move to any position around the edge of the clock and the clock will chime as the hand passed over the marker.

I was hoping for some advice, as to the best / simplest way to do this.

Thanks

How do you intend to read the "markers"?

The markers, mark the time that the clock will chime. What I would like is a switch or sensor that know where the maker has been placed and can chime at that time. e.g. If you wanted the clock to chime 12:00 you would place a maker at 12 o'clock and so on. The idea is to mark important moments in your day and you change the makers each day.

e.g. If you wanted the clock to chime 12:00 you would place a maker at 12 o'clock and so on.

Plus or minus how many minutes?

Having an LED and LDR outboard of the clock face, blocked by the markers, not blocked otherwise, seems possible.