# Street light circuit

#### nayr922

Joined Apr 23, 2022
1
Hello Everyone,

I am designing a circuit that operates on pressure sensors to turn lights from red to green, green to yellow, and yellow back to red. I am implementing 2 of the 4 sides of an intersection due to redundancies. How would I design a circuit with 2 inputs and 2 outputs? My plan is to use pressure sensors to detect the first "car" that approaches the intersection and turn that light from red to green using a timer circuit. I already have the timer circuits constructed and working independently, but the logic to choose between the 2 is throwing me off. Any suggestions?
Truth Table
A B | R1 R2
0 0 0 0
1 0 1 0
0 1 0 1
1 1 This is where I get confused because it is supposed to be like a flip flop so that either one would be 1 depending on which was triggered first.

#### dl324

Joined Mar 30, 2015
16,134
Welcome to AAC!

What are R1 and R2? How do they relate to A and B?

As this is homework, you need to provide your best efforts at a solution.

It would be helpful if you described how the pressure sensors are being used. When a car comes to the intersection and the light is red, how does that cause the other light to cycle to yellow and then red? The complete text for the problem would also be helpful.

#### ci139

Joined Jul 11, 2016
1,898
1 1 This is where
You're right - this is an exception where it is impossible to determine the priority as it was insisted by your plan
. . . you can make a prevalence on site depending on other factors as . . . safety , approach speed (in the sense of - which car is less likely to manage to stop depending on the active state of the traffic light) , etc.

#### Picbuster

Joined Dec 2, 2013
1,045
Hello Everyone,

I am designing a circuit that operates on pressure sensors to turn lights from red to green, green to yellow, and yellow back to red. I am implementing 2 of the 4 sides of an intersection due to redundancies. How would I design a circuit with 2 inputs and 2 outputs? My plan is to use pressure sensors to detect the first "car" that approaches the intersection and turn that light from red to green using a timer circuit. I already have the timer circuits constructed and working independently, but the logic to choose between the 2 is throwing me off. Any suggestions?
Truth Table
A B | R1 R2
0 0 0 0
1 0 1 0
0 1 0 1
1 1 This is where I get confused because it is supposed to be like a flip flop so that either one would be 1 depending on which was triggered first.
Hi,
Make a state machine.
Each state is a condition of lights like
state 1:
road a: red on rest off
road b: green on rest off
etc.
state 2:
orange handling
state 3:
.
.
..
State N:

action: jump to the state you want but don't forget the orange cylce !
the rest for you to work out.

Picbuster