So, I want to build a timer in the style of an old-school flip clock (like this http://www.ladidah.com.au/range/images/flip-clock-grey.jpg) that counts from 000:00 minutes to 108:00 minutes. Whenever a user enters a certain sequence of numbers on the computer, the timer should reset itself to 000:00. I'm brand new to electronic projects. I reckon I can connect the output of a 555 to a flip clock motor and calibrate the gear train appropriately (haven't quite worked out the reset function yet). The thing Im not sure about is how to get my computer to directly affect the circuitry (i.e. reset the timer after the sequence is entered). Does this require specialized software? I've got an old Commodore 64 laying about that I think would work pretty nicely. Is this something that is feasible for a newbie? Is their any documentation out there I should be reading up on? Thanks!