4-Way Traffic Signal with Arduino

[jimbobones]

Over the past two weeks, I’ve purchased an Arduino Uno starter kit and learned how to write code for it. After doing some of the basic tutorials, I moved on to things that will be beneficial to me and other model railroaders. My first big project was to test & mock up a 4-way intersection with working traffic signals. I have my lights sequenced as Green for 20 seconds, Yellow for 5 seconds, all directions Red for 5 seconds and then set up to repeat in the opposite direction. Attached are some photos, of my breadboard tests and mock up. Once the breadboard testing was complete, I transferred the code to an Arduino Nano for permanent use on the layout. If anyone has interest in my code and components used, just let me know and I’ll post them. Happy Railroading, Jim

4-Way Tinker.JPG4-Way Bread.jpg4-Way Nano.jpg4-Way Mock1.jpg4-Way Mock2.jpg

[RailKing50]

Neat project! Please post the code and info about the street lights. I am sure that I am not the only one interested.

[jimbobones]

Per @RailKing50 's Request;

1. The traffic lights I found on eBay. Currently there aren't any more available but I'm sure there will be more soon. It's from a seller who deals a lot in HO / N scale LED street lamps, signals, etc. I shot him a private message to see when he might have more in and will let everyone know. I bought the last 8 he had but would like to buy more now that I know the work well.

2. The Green lights are about 50% brighter than the Yellows and the Reds so I'll be adding resistors to the Green wires to "dumb" them down a bit. I'll post which resistor value works best to even them out once I've tested them.

3. Arduino Code Below - NOTE: This is for common Anode wiring (Black Wire with resistor to Anode / Red, Yellow & Green Wires to separate Cathodes so a digitalWrite LOW lights the LED's not digitalWrite HIGH.


*** SEE REVISED CODE IN THE POST BELOW ***

[Chicago Rail]

Very cool traffic lights, I’ll keep an eye out for more,,,,,,
Arduino,,yet another thing I have that’s still in the queue to work with along with my 3d printer kit.

[NtheBasement]

Can you label the pins something like Nred, Ngreen, Nyellow etc. Then it could look something like

digitalWrite(Wyellow, LOW);

Otherwise I'm having a hard time figuring out whats what in the code, although I'm sure I could map it out from the photo.

[pbender]

Can you label the pins something like Nred, Ngreen, Nyellow etc. Then it could look something like

digitalWrite(Wyellow, LOW);

Otherwise I'm having a hard time figuring out whats what in the code, although I'm sure I could map it out from the photo.

You certainly can.

You add a line like the following for each pin you want to name:

#define Wyellow pin

Where pin is the number of the pin you are naming

One other simplification here, you only need 6 outputs for the signals you have. Think about this, the east and west signals always show the same thing, as do the north and south signals.

You can easily connect two LEDs either in parallel or in series to the Arduino outputs.

Paul

[jimbobones]

Hey pbender,

I did exactly as you suggested when I did my mock up last night and only used 6 pins instead of all twelve like my original breadboard setup. I bought two sets of lights (8 total traffic signals) planning to use one nano to control two complete intersections (or maybe even more) so, that's why I wrote the code to use all 12 digital pins. But, with the Nano's only costing about $4.75 each, they're affordable enough to have several on the layout controlling just a few lights each.

NtheBasement,

I'll re-write my code tomorrow and post it defining the pins as names to make it easier to understand.

[Nskale]

That's cool - I did a 3-way for my last layout controlled by arduino, but on this one I haven't re-installed the controller, but I did mount the three-way traffic lights wired as a static setup. Perhaps in the future I will get it all working again.

[jimbobones]

@NtheBasement

1. Below is the revised code you've requested. It's trimmed down so only six pins are used as @pbender suggested. In this setup, two Traffics Lights are connected to Pins 2,3 & 4 and the other two Traffic Lights are connected to pins 5,6 & 7. Sorry for the delay, I was watching the Rolex 24 at Daytona.

To all,

The traffic lights will be available on eBay again after Chinese New Year on Feb. 11th, 2019. The seller's name is wehonest_us - he's US based selling goods from China with over 10,000 sales under his belt and has 99.7% positive feedback.


/* American Traffic Signal for North/South - East/West operation.
* Length of time for lights can be adjusted by changing the delay times.
* Have fun with it. Jim Barclay Version 2 012719
*/

int trafficDirection = 0; //Set Traffic Direction to North/South

#define NS_Green 2
#define NS_Yellow 3
#define NS_Red 4

#define EW_Green 5
#define EW_Yellow 6
#define EW_Red 7


void setup()
{
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
Serial.begin(9600);
}

void loop()
{
digitalWrite(NS_Green, LOW); // North/South - GREEN - East/West - RED
digitalWrite(NS_Yellow, HIGH);
digitalWrite(NS_Red, HIGH);
digitalWrite(EW_Green, HIGH);
digitalWrite(EW_Yellow, HIGH);
digitalWrite(EW_Red, LOW);
delay(20000); // Wait 20 Seconds


if (trafficDirection == 0) {
digitalWrite(NS_Green, HIGH); // North/South - Turns YELLOW - East/West - RED
digitalWrite(NS_Yellow, LOW);
digitalWrite(NS_Red, HIGH);
digitalWrite(EW_Green, HIGH);
digitalWrite(EW_Yellow, HIGH);
digitalWrite(EW_Red, LOW);
delay(3000); // Wait 3 Seconds for YELLOW light

digitalWrite(NS_Yellow, HIGH);
digitalWrite(EW_Red, LOW);
digitalWrite(NS_Red, LOW);
delay(5000); // Wait 5 Seconds where both direction are RED

trafficDirection = 1; //Change Traffic Direction to East/West
Serial.println(trafficDirection);
}

digitalWrite(NS_Green, HIGH); // North/South - RED - East/West - GREEN
digitalWrite(NS_Yellow, HIGH);
digitalWrite(NS_Red, LOW);
digitalWrite(EW_Green, LOW);
digitalWrite(EW_Yellow, HIGH);
digitalWrite(EW_Red, HIGH);
delay(20000); // Wait 20 Seconds

if (trafficDirection == 1) {

digitalWrite(NS_Green, HIGH); // North/South - RED - East/West - Turns YELLOW
digitalWrite(NS_Yellow, HIGH);
digitalWrite(NS_Red, LOW);
digitalWrite(EW_Green, HIGH);
digitalWrite(EW_Yellow, LOW);
digitalWrite(EW_Red, HIGH);
delay(3000); // Wait 3 Seconds for YELLOW light

digitalWrite(EW_Yellow, HIGH);
digitalWrite(EW_Red, LOW);
digitalWrite(NS_Red, LOW);
delay(5000); // Wait 5 Seconds where both direction are RED

trafficDirection = 0;
Serial.println(trafficDirection);
}
}

[NtheBasement]

@jimbobones thanks for the update. No problem with the timing; I'm interested in learning how to program arduinos for my own nefarious purposes. The code makes sense standing by itself and is easy to follow.

[jimbobones]

@NtheBasement

I have a background in I.T. and have learned a few programming languages along the way. For example, Visual Basic, so after buying a $35 kit on Amazon (which includes an Uno clone) and watching a few Youtube videos on the Arduino, I found it the easiest language to learn, especially for lighting LED's or activating servo's for example. Two concepts that can help automate a model railroad and my main reason for learning with the Arduino. Here's where I got started.

Learning Kit by Elegoo

https://www.amazon.com/gp/product/B01D8KOZF4/ref=ppx_yo_dt_b_asin_title_o04__o00_s00?ie=UTF8&ps c=1



Great Youtube Video Series on the Arduino

https://www.youtube.com/watch?v=09zf...eapCS_UrsgfuJA




A Drag and Drop way to write code and make a graphical working prototype

https://www.tinkercad.com/circuits


Have fun, Jim

[RailKing50]

@jimbobones - Thanks for uploading the code. Little things like this really bring a scene to life!

I am working on wiring up the upper floors in my buildings to random cycle LEDs on and off to look as if someone is moving between rooms using an Arduino Mega. I have the basic code and lights, just need to finish all of the interiors......

The traffic lights will be available on eBay again after Chinese New Year on Feb. 11th, 2019. The seller's name is wehonest_us - he's US based selling goods from China with over 10,000 sales under his belt and has 99.7% positive feedback.

I have bought from this seller before and would do it again! Thanks for digging into the restock time line.

[jimbobones]

@RailKing50

Are you going to randomly light the rooms or follow a sequence? Also, please post photos or your interiors when you have one or more done so we can see how you block off individual rooms.

My next Arduino project is to put Red "blinking" lights on top of tall structures like my Grain Elevator. Instead of just blinking on and off, I'm going to have them fade in & fade out mimicking incandescent bulbs which I think will look better.



Jim

[RailKing50]

@jimbobones

In the code I will name each LED and then turn them on and then off later in the code. It will just be on a continuous loop.

I am sure there are better ways of doing this, but for me I know how to do it that way so I am going to stick with it! K.I.S.S

[jimbobones]

@RailKing50

You might find this interesting...

https://www.youtube.com/watch?v=k8iCOa0slXo&t=332s

[NtheBasement]

@jimbobones

In the code I will name each LED and then turn them on and then off later in the code. It will just be on a continuous loop.

I am sure there are better ways of doing this, but for me I know how to do it that way so I am going to stick with it! K.I.S.S

Would this work for a loop? Use random(2,13) to generate an output pin, turn it on, then random(5000 or so) to wait, then random(2,13) again to turn one off, then another wait? Half the time the light will already be in that state but it shouldn't matter (I think).