What Hardware Do I Need To Buy Besides a PLC to Run a Traffic Light Program?


Thread Starter

Craig Y.

I need to purchase a PLC and hardware so that I can program it to run a 4 way traffic light program. I must demonstrate that it can function properly and switch the lights in the proper sequence and at the proper time. I have taken a class in automation so I have some experience with ladder logic programming in RS Logix Pro 500. But we did not get to actually run the program on a real PLC so I do not know exactly what I need to purchase to accomplish this project. At DeVry University they were too cheap to purchase the required PLC and hardware so I have to purchase one in order to complete my Capstone Project so I can receive my Degree. Any help would be appreciated here because I do not know what parts I need besides the PLC, switches and lights. I am running on a shoestring budget so I need a very cost effective plan for my project. I am a disabled veteran and am trying to finish my degree so I can get a job and go back to work.

Craig Y.
You'll need a PLC, software to program it, a cable over which the software talks to the PC, a PC, and presumably some lights and switches to simulate intersection traffic lights. I doubt you need actual vehicle sensors (due to cost); ordinary switches can simulate the function.

On the extreme low end of hardware, there's www.ezautomation.net with plastic PLC components.

A step up is Automation Direct. One of the best aspects is their video and tutorial support. Their 100 page automation tutorial manual is excellent as is much of their documentation. I know integrators who routinely use Automation Direct for their customers' low end applications.

Be sure to inquire as to the cost of the programming software, because hardware without the appropriate software is useless. Many of the major brands/models will be excluded for a project like yours due to software costs.
Ok, I'm going to take a deep breath before making this recommendation. In any other circumstances, I wouldn't say the same thing.

Look at the Allen-Bradley MicroLogix 800 line. The 810 may do it. We bought one as an experiment, it cost us about $80 for the unit, and maybe $25 each for the LCD screen add-on and the USB port. The software is free, if you don't mind waiting forever for a huge download (1.64GB according to the website). I personally don't like the software and would never recommend it for a production environment, but it's probably ok for this.

See here:
Another option open to you is to contact any industries in your area and see if they can lend you what you need. As noted by another reply, the list of components needed is relatively small. I know one plant I worked in worked with the local high school on projects like this. We let the kids use the components - conditionally of course - and it proved to be a "win-win" for all.
If DeVry requires you to purchase an expensive PLC, please give me the details.

I am DeVry alumni, although I graduated many years ago.

Please give detail on DeVry location and requirement.

I will contact them personally.

I would recommend a Raspberry PI microcontroller which has the I/O to complete the dreaded street light project.

A few resistors, a couple of 7 segment LED, optical sensors for cars would be cool, and a breadboard will complete your project.

One should not need a big time PLC and the cost associated.

Curt Wuollet

Yes, I've installed at least 40 Automation Direct Clicks with no issues. At $69 for a basic PLC with free software, I don't think there's a better deal out there.

And yes, you could probably make a raspberry pi work, but you would need to know C or Python to do it. I have a machine vision project I'm working on with the RPi 2 and it's a stellar low cost platform.

You may go for a cheap yet reliable Delta series PLC's. Software comes free.

You will need a DC power supply according to your PLC (Some PLCs Have embedded AC to DC converters.
Use a cheap PC Switching Power Supply card for the same.

I believe you might be familiar with source/sink wiring (If using relays).

If you want to keep things simple, use color LED with resistor combination to represent an actual signal light ( Originally using relay card switching combination)

And wires(with termination) obviously.

You might need a communication cable to connect your Programming computer with the PLC.

If you require to mount the system, you have to use cardboard / Mica based boards and plastic troughs for neat wiring.

Fasteners, for the same.

You can go fancy with additional sensors and modes and push buttons for pedestrian crossing.

Hope that helps.

I have used the Automation Direct PLC with great success. used them years ago to replace aging Modicons with the suit case 286 programmer console.

But for a graduation project at DeVry. NO!!

Free code for the project available on the Internet!!

The PI2 has all the I/O onboard. Once one has presented that you can turn on a couple of LEDs, or even present the stop lights on a 75" Samsung flat screen.

Then::reboot to the OpenElec operating system and watch a movie.

Gotta have fun,