I guess everbody knows the nerve killing game in which you have to guide a metal loop along a curved wire. If the loop touches the wire you have to start all over or go back to the last save-point. The project below describes how to build such a game with a PIC16F628A and 3 7-segment displays.

Part list:

• PIC16F628A
• 3 x 4511 (7-segment latch/decoder/driver)
• 3 x 7-segment displays: common cathode
• 7805 voltage regulator
• A buzzer (5 volt)
• BC547
• 1 on/off switch
• 1 switch normally open (for starting/pausing the game)
• many resistors
• A 2 meter M6/M8 metal thread
• A piece of solid wood
• Flexible cord (I used an old "shaver cord")

The schema below puts it al together. Notes:

• Switch 1 is the on/off switch.
• Switch 2 is connected to the wire loop(p1) and to the wire maze(p2).
• Switch 3 is the start/stop/reset switch.
• The BC547 acts as an on/off switch for the buzzer. It buffers the PIC16 output in order to avoid to draw too much current from the PIC.
• Use 40cm of the metal thread for the wire loop plus handle. Bend the remaing 1.6 meter of the thread in the desired curves.

You can download the source code or hex file