CrossRoads: If the uC commands the motors to position 5, and then reads back from the switches what actually ended up, say 7, it can rotate the motor thru again, and stop it sooner the next time. That's where we are coming from. If you are not reading the switch info in, then yeah, it doesn't solve anything.
I don't follow the shift-out register to the switches & OR gates to turn the motor off yet.
The situation you mention is theoretically impossible (unless power is cut mid flip to the entire board).
The OR gates might be completely useless. I am doing a simple test circuit using LED's instead of motors to see if I can simulate the whole works. The key to realize is that the flipping of the cards, through the rotation of the wheel driven by the motor is the mechanism that actually kills the motor. When the HIGH signals being sent from the shift register to each display go to the switch banks, the cards themselves physically interact with the switches. When the correct card flips to the position, it flips the switches that had the HIGH signal. Thus opening the circuit which drives the mosfet gate LOW which opens the circuit to the motor which stops the spinning.
At least, that is what I am attempting. And I will know how bad I messed this up once I get the test circuit done. The first thing I had to add was a 100k pull down resistor at the gate of the mosfet so the circuit would open reliably.
TomGeorge: Hi, sounds like the mechanical flip type displays that were/are used at airports displaying flight information. We have a clock that has flip type digits, wife says its over 30years old, still runs, one D cell per year weather it needs it or not.
Yep, you got it. I am a huge train board game nerd (specifically 18xx series of games). The idea is to make an interactive display board with company name, stock price, and payouts. IF I can get this working, then it opens up a lot of other ideas I have in regards to split-flap displays.