Explanation of variables
Inputs: Open switch, Close switch, Open limit, Close limit
OS: This input is represented by one of the buttons (B0) on the Digital Minisystem or DMS. When pressed the gate starts to open.
CS: This is represented by another button (B1) on the DMS. When pressed the gate starts to close.
OL: This is the upper limit switch at the top of the build. When activated by the gate bumping the switch, it tells the motor to stop.
CL: This is the lower limit switch at the bottom of the build. When activated the limit switch tells the motor to stop.
Outputs: Motor Open, Motor Close, Gate Open, Gate Closed
MO: The motor open signal output activates after the Open switch input has been activated or pressed. It tells the motor to rotate to the right, opening up the gate.
MC: The motor close signal output activates after the Close switch has been activated. It tells the motor to rotate to the left, closing the gate.
GO: This Output is represented by a LED and when activated it indicates that the gate is fully open.
GC: This Output is represented by second LED and activates when the gate is fully closed.
OS: This input is represented by one of the buttons (B0) on the Digital Minisystem or DMS. When pressed the gate starts to open.
CS: This is represented by another button (B1) on the DMS. When pressed the gate starts to close.
OL: This is the upper limit switch at the top of the build. When activated by the gate bumping the switch, it tells the motor to stop.
CL: This is the lower limit switch at the bottom of the build. When activated the limit switch tells the motor to stop.
Outputs: Motor Open, Motor Close, Gate Open, Gate Closed
MO: The motor open signal output activates after the Open switch input has been activated or pressed. It tells the motor to rotate to the right, opening up the gate.
MC: The motor close signal output activates after the Close switch has been activated. It tells the motor to rotate to the left, closing the gate.
GO: This Output is represented by a LED and when activated it indicates that the gate is fully open.
GC: This Output is represented by second LED and activates when the gate is fully closed.
Physical Process
When the Open switch button is pressed, the Gate closed LED turns off and the Motor open signal activates, opening the gate. The gate opens till the Open limit switch is activated, stopping the motor and turning on the Gate open LED on. Then, the Close switch is activated, turning off the Gate open switch and sending a signal to the Motor close to start closing the gate. The gate closes till it hits the close limit switch, stopping the motor and tuning on the gate closed LED.
Conclusion
To start off this project, we had to use the table on the front of the toll booth project to define and understand the variables. After completing that, our group moved on to the state transition table and filled it out so we could get the variables we needed to later K-map. Then, when the K-mapping was finished we wrote down the expressions and applied Boolean algebra to them to get the simplified expressions for the input and output combinational logic. Next, we could move on and build the circuit on Multisim. Then came the construction of the vex toll booth build which was fairly simple and enjoyable. We uploaded the Multisim circuit to the chip companion, that was so generously provided by Mrs. Z, and tested to see if the sequence would work. The first time the build did not function and the motor chip almost blew up. After quick troubleshooting and revisions, we finally got the toll booth to function the right way. We definitely made some mistakes when we were required to explain specific components or where a part came from or what that component did, but every time we discussed it and persevered till we got all the answers right. Some major components of this project included: the open and close limit switches, the motor and the expressions that are used to run the whole program itself. This project was very similar to the Date of Birth project we did, but it is a bit different because of the vex build that we had to upload the circuit to. One thing I learned about reading schematics is that they are a bit condensed so translating them to the board can be a bit hard. I also learned that the long bar on an external power is positive and the short bar is negative. This was definitely easier to do at the ed of the year due to the greater span of knowledge we have gained in this field. Next time I would check the connections better before testing the build out.