Hmmm. Let me venture a guess... you have a board game with tokens or objects arranged, more or less in a circle surrounding a central point, wherein a needle arrow, presumably mounted on a pivot to allow the needle to spin about the pivot, can be spun by a player's hand. Eventually the needle will stop and point at one of the objects or tokens, whose symbolism dictates the next move of that player. Sort of like the "Wheel of Fortune" or "Price is Right" television program where players take turns spinning a giant wheel to collect money prizes, or lose turns, or whatever "surprises" come up. You want a "Wheel of Fortune" that plays on a horizontal board, and perhaps has segments that "light up" as the arrow rotates to point at them. The rub comes if the arrow stops between two adjacent segments, with no one segment indicating the "winner" of that spin of the arrow. So, you need an electronic means to eliminate the ambiguity.
The television Wheel of Fortune uses a ratchet mechanism to ensure the wheel stops at discrete locations pointed to by a fixed pointer. One scheme uses several pegs in each segment that the fixed pointer is forced by the mechanics of the situation to always land between, Thus there can be no doubt as to which segment the pointer has selected, although there is considerable suspense as the wheel slows down and the pointer flaps between the rotating pegs.
A similarly functional arrangement could be designed into a spinning pointer on a horizontal board game by placing small rare-earth magnets on the board to replace the pegs of the commercial version. Then, after the needle has been spun by hand, it will pass over each of the magnets in turn until it slows down enough to be attracted to and remain over just one of the magnets. Then all you need to do is detect the position of the arrow pointer, i.e., determine which segment it stops on. A rotary shaft encoder could easily do this, or perhaps you could embed sensors under the path of the arrow needle to determine which segment it landed in.
There are really two separate problems that must be solved to make this type of game both fair and possible, First problem is to guarantee that the pointer will always unambiguously point to one, and only one, segment. The second problem is to identify (electronically, so you can select an audio file to be played) the segment the needle pointer has selected.
Of course, if I have incorrectly guessed the intent of what you want your magnetized needle to DO... well, never mind.
But, if I am on the right track, magnetic reed switches can serve both the purpose of ensuring the arrow pointer lands only within discrete areas of each segment, as well as providing electric position indications of the selected segment. The spacing between each reed switch and the magnetized needle will be critical to seeing that the pointer is attracted and eventually held stopped relative to one particular reed switch. This can be accomplished with careful mechanical design and some testing to determine the optimum spacing between reed switch and magnetized needle before constructing the final board. Perhaps you could use a strong plastic, such as Lexan (polycarbonate), to mount and glue all the reed switches into shallow recesses milled into the panel, and to accurately mount a low-friction bearing support for the magnetized needle that allows it to pass over, and be attracted to, the reed switches when it's spinning slows down enough to allow the needle to be "captured" by one of the reed switches. This construction technique may eliminate any requirement to embed strong magnets in each segment to fix the "landing" positions of the needle.
Building such a device could make for an interesting home board game. Commercial prospects are nil. As soon as anyone who begins manufacturing and selling such a board, they will soon find that there will be bells and whistles added by Asian manufacturers and their product will undersell your product to the point where yours will become unprofitable to manufacture and distribute. Capitalism and cut-throat business practices have now been exported free to the world!
However, one of the nice things about this forum is it encourages folks to learn how to make "one off" projects and this sounds like it would be a good one. Playing sound bites associated with each segment is innovative. Be aware that by my mentioning this here, the idea will be stolen and implemented elsewhere, but that can't stop you from enjoying your own DIY board game.
