State Machine for Railway-Crossing Indicator. I don't get it.

[brightjoey]

1st of all I wanna thank you for taking your time to read this post. I know there are many other busy important things that you may have, So once again I want to thank you for giving this thread your attention. All of them using LED's as output.


5 outputs
1) Area 1
2) Area 2
3) Area 3
4) Flashing Light
5) Warning Bell

**broken link removed**
( Forgive my Drawing )

Area 1 & Area 3
Flashing Light and Warning Bell Will be turned on when trains enter from either side.
Flashing light will flash for 3 seconds.
Waring bell will turn on for 4 seconds.
Area 1 or Area 3 lights up depending on wher the train is.

Area 2.
Area 2 light on.

No Train
All outputs are off.

Tips
Use counters to keep track of time for flashing light and warning bell.

Haha I still don't understand. Is there any reading material on where to begin? I guarentee I will follow till the end.

 

[colin55]

I have kits and projects for the crossing and crossing lights, using photo transistors, if you want them.

 

[3v0]

Do you understand what a state machine is ?

If not read up on that and then make a post to let us know you are up to speed. If you have trouble with its nature we can talk about that too.

If you do have you identified any states or transitions ?

 

[brightjoey]

@Colin55 Thanks for the offer but I want to know the theory behind it 1st. What I do know is that I don't think ill be using phototransistor to construct, but using some flip-flops, counters.

@3v0, Yes I do know about state machine but I won't mind if you wanna give me some reading material.
This is my reading material
**broken link removed**
I wanna clarify that I'm still abit shaky on this gound.

Basically I want to assign switch 1, 2, 3 as area 1,2,3 respectively.

Do I need to use Mealy or moore diagrams? IS this a sequential circuit?

 

[3v0]

The document is very good if you read and understand it you will have no problems.

Yes assign switches to areas.

Then make a diagram using circles to show the next state based on the value of the current state, the switches, and the counter.

It is a sequential circuit.
Do what the document says.

 

[brightjoey]

This is the part I don't get. What sequence? I don't see any visible sequence.

Usually if its a sequence it would be like "1101" or "0011" but I don't see how to implement it.

Unless, the sequence would be 10101. where the 1st "10" signifying S1 turn on and off. 2nd "10" signifying S2 turns on and off. and the last "1" signifying S3 turns on..

But How can I implement a sequence with 3 difference switches .