This of course depends on the size of the street, the speed limit, and other factors.

Timing Light Sequences: Build a Traffic Light Controller with an Arduino MEGA.

Traffic lights are one of those things that, for most people, seem to blend into the landscape of everyday life.

Wherever there are a moderate amount of cars, there will probably be one of these devices present.

Modern day traffic lights are pretty complex within and have all kinds of sensors, timers, and even traffic monitoring systems that they employ to help efficiently control the rate of traffic.

It will also help think through a problem and design logically to meet certain criteria.

As a bonus, this project helps us appreciate how traffic lights work, at least at the basic functional level.

As mentioned before, modern traffic lights can monitor traffic, change light cycles for pedestrians requesting to cross, know when to change its timer for increase traffic flow, etc.

That is to say that the light has no feedback and will simply run without regard to the traffic volume.

Even though this is not an intelligent light, we can implement this system in an intelligent way.

From the towns traffic history conducted by the local police municipality, we find that Busy Bunny Lane is busier than Lazy Tortoise Ave (shocking).

Since we know the typical traffic flow of this intersection, simple timer-based control is appropriate.

The rest of the control and logic will be performed by the Arduino.

That means it will turn each light on and off and will count the time that each one should be on.

You could use a digital input to switch the operation, but that would need wire which is not listed on the bill of materials Loop Sequence (USA Style).

To make this easier to illustrate, we are going to use a timing table to help us better visualize the entire loop sequence.

For both streets, it is permissible to have the amber traffic light on for 3 seconds.

For the red traffic lights, the green and amber cycle times will directly influence this.

It is not necessary to break it down into seconds, but for the point of example and illustration, it might be easier to digest if you are attempting something like this for the first time.

Once you have reached the end of the table, the entire thing starts all over again.

If you look closely, there are two instances where both lights are red.

Before reading on, try to think about why this design choice was made.

Verilog Traffic Light 3Way