# 3 traffic lights

Thread Starter

#### rosol

Joined Dec 15, 2020
4
HELLO EVERYBODY!
i have this project to do but i really can't draw the state diagram and even the truth table is really long if i think about to make a
7 inputs and 12 outputs that's really long
SO any suggestion plzzzz!

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#### MrChips

Joined Oct 2, 2009
22,531
Is this homework related?

Thread Starter

#### rosol

Joined Dec 15, 2020
4
Thread Starter

#### rosol

Joined Dec 15, 2020
4
Is this homework related?
DO YOU HAVE ANY SUGGESTION OR SOLUTION ABOUT DRAWING THE STATE DIAGRAM FOR THIS?

#### n1ist

Joined Mar 8, 2009
189
You need to figure out what should be done in the following cases:
- You are waiting for a light to change and the road sensors change
- When you change into an sequence, where in the sequence do you start?
- How to handle time
- How to handle the day/night switch (for now, I would just assume it is a binary signal coming from some black box)

Once this is done, you will need to just list all the inputs and outputs and methodically fill in the table

#### WBahn

Joined Mar 31, 2012
26,398
You are GIVEN the definitions of all of the states and well as a description of how you move between then based on the inputs from the three sensors.

So make a table that has one row for each state and one column for each combination of the sensors. Forget about the time aspect for now (10 sec for green and 3 sec for yellow).

Don't worry about Day/Night for now.

Fill in the table according to the descriptions and show your best attempt.

It might help to focus on one sequence at a time. Start with the most general case, when the sensors are 111. Then do the most restrictive cases when either no or only one sensor is HI. Then do the cases when two sensors are HI. Then start asking about how to switch from one sequence to another.

Thread Starter

#### rosol

Joined Dec 15, 2020
4
You are GIVEN the definitions of all of the states and well as a description of how you move between then based on the inputs from the three sensors.

So make a table that has one row for each state and one column for each combination of the sensors. Forget about the time aspect for now (10 sec for green and 3 sec for yellow).

Don't worry about Day/Night for now.

Fill in the table according to the descriptions and show your best attempt.

It might help to focus on one sequence at a time. Start with the most general case, when the sensors are 111. Then do the most restrictive cases when either no or only one sensor is HI. Then do the cases when two sensors are HI. Then start asking about how to switch from one sequence to another.
thank you so much!
here i go i'm trying all my best to solve this project and actually
i'm in love with digital design but you know sometimes you got stuck in something and you feel nothing to do!