Help needed for making a pinball machine.

[pocky]

Hi, i'm making something like a pinball machine for my tech class and i wanted a way to show the score digitally like on a led digit display. I searched google for something like it but i couldn't find anything. I was thinking of ripping out the electronics from another pinball machine and putting that into my own but it cost's more than my budget. I need something that when the metal ball hits the contacts it would result in points that would show up on the led's. and i want the points to add up just like a normal pinball machine. I know little about electronics and any help on this would be greatly appreciated.

[OnOff]

This is a very simplified design just to give you an idea.
You may use any cheap micro.
If the 7seg is CC then you should use BC337 instead of BC327.

If you need more help tell me.