how can i design this logic circuit?

Question

* We need to design a logic circuit to control an elevator door in a three-floors bldg. The circuit has four inputs. M is a logic signal that indicates when the elevator is mocing (M=1) or stopped (M=0). F1, F2, and F3 are floor indicator signals that are normally LOW, and they go HIGH only when the elevator is positioned at the level of that particular floor. For example, when the elevator is lined up level the second floor, F2=1 and F1=F3=0.
* The circuit output is the open signal which is normally LOW and is to go HIGH when the elevator door is to be opened.
* design the logic circuit to produce an OPEN door for stated conditions: simplify the expression and implement the circuit in gates.

Guys , i'm a student .. first year .. and it's a bit confusing these kind of problems .. :S ..

Answer 1

So, if M=0 AND F1, F2, or F3 = 1, then OPEN = 1.

(Not M) AND (F1 or F2 or F3) = 1

M will be fed through an inverter. F1, F2, and F3 will be fed through a 3 input OR gate, or an arrangement of 2 * 2-input OR gates. The outputs of the inverter and OR gate will be fed through a 2-input AND gate. The output of the 2-input AND gate will be your OPEN signal. Click the link to see a basic topology of the circuit.

http://i83.photobucket.com/albums/j314/Jshwaa/elevatordoorlogic.gif

Answer 2

There are some people who should be engineers and there are some who try to fake it and piss the rest of us off don't be that guy. The reason you can't answer this question yourself is because you haven't earned the right to be an engineer and you're a slacker, go be a janitor.

Answer 3

Ah yes ...I remember doing the same thing about thirty years ago. You need to do it on your own and not with anyone else's help. If you don't you run the risk of getting a job, falling flat on your butt, getting fired and working for Wal-Mart. Good luck.