Traffic Light Circuit

Discussion in 'The Projects Forum' started by dock490, May 30, 2016.

  1. dock490

    Thread Starter New Member

    May 30, 2016
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    Hi All,

    My friend an I are art students at university and are currently working on a project that will be installed in a forest. We are putting two traffic lights in the forest and are currently trying to work out the electrical side of the project. because of accessibility to the forest we have decided to use solar power and we have been limited to 12V due to health and safety. Originally we were going to get help to build the circuit and do the wiring but our electrician friend has bailed. This is our plan at the moment:

    2016-05-30 12.47.04.jpg

    First of all is the power source. We saw this in Maplin's and we think it might do the job.
    http://www.maplin.co.uk/p/hubi-2k-solar-lighting-and-power-system-n18ek
    The only question is whether we can run a circuit from a cigarette lighter. Is this possible? and what adapter would we need?

    Next is the circuit board. I discovered this website the other day that sold traffic light circuits designed for 12V model railways. Would this work?
    http://www.modellingelectronics.co.uk/products/traffic-light-control.php
    If so, our main problem then is to connect the traffic lights over a long distance, about 5 meters either side. What kind of wire should we buy that is weatherproof and is compatible with the circuit.

    The final part is the connection to the lights. We currently have 6, 12V ultra bight led's to put in the traffic lights. How would we connect these to the wires safely and would it involve soldering.

    I know there are a lot of question here but we both have a very basic knowledge of electronics and circuits and have no experience of creating circuits like this before.

    Any help would be greatly appreciated.
    Thanks.
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
    3,250
    626
    Welcome to AAC!

    What is the function of the traffic lights? Stop, go, caution? What controls them?

    What is the current requirement for the LEDs? What is the current capacity of the solar cells and battery? What runtime is required? Will lights be on continuously?

    12V is relatively safe under damp conditions. 5M distance shouldn't be an issue as long as wire gauge is sufficient.
     
  3. dock490

    Thread Starter New Member

    May 30, 2016
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    0
    The function is a simple stop, go caution which is mirrored in the other traffic light. This is the defined sequence of the circuit board we are thinking of buying.

    sequence.png
    The capacity of the solar cell and battery: on the website it states that is "Provides 3-4 hours of light when fully charged" and "Battery pack has multiple power outputs - 3 x 12V and 2 x 5V USB." It is designed to work for long periods of time for outdoor lighting.

    The run time of the project is three months and the lights will only need to be on a couple of hours a day as the peak visiting times are mid to late afternoon. Therefore we would have to fit a timer.

    What do you mean by the requirement of the led's?

    Also how do we check if the wire gauge is sufficient, sorry if these questions are basic, i just want to make sure i dont buy any of the wrong components. Thanks.
     
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    First, you can run your circuit from a cigarette lighter. You can find the "adapter" or plug at an automotive supply store.

    Next, you will have to determine the specifications of the LED. That is, its operating voltage and current. It should be on the site or packaging of the units.

    Then we come to the traffic light controller. The main question here is will it supply enough current to power your selected LEDs? I think not. It is designed to only light very small LEDs in an N scale model. You likely would have to design a driver module for your LEDs.

    I suspect (without having the LED specs) that you could use Cat 5 or 5e cable to connect your traffic lights to the control module. You can get this at a home improvement store if you don't have a nearby electronics supply house. If not, there is four conductor cable available, either at aforesaid home improvement center or online.

    What do you foresee as using for your timer? It is going to require power as well. At this point I am compelled to say a small microprocessor could drive this whole thing. An Arduino is one choice and fairly simple to kearn, particularly if you've ever coded before.

    Lastly, where are you going to put the solar panel? If this art exhibit is going to be in the forest, the sunlight for the panel is going to be greatly filtered and may not be enough to power your lights and control circuit.
     
  5. dock490

    Thread Starter New Member

    May 30, 2016
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    Thanks for the help.

    This is looking much harder than I expected. I'll talk with my friend about these options and things that we will need to change.

    However, Disregarding everything I have said, is there a better solution to our problem. If anyone can think of a simpler way of getting this to work it would be much appreciated. We haven't purchased anything yet we can completely change to technical side of the project.

    Thanks.
     
  6. eetech00

    Active Member

    Jun 8, 2013
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    A cool project would be to use two Rasberry Pi's, one to drive each traffic light assembly.
    Then have them communicate wirelessly with each other using Bluetooth or WiFi.

    However, what type of traffic are you controlling?
     
  7. dock490

    Thread Starter New Member

    May 30, 2016
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    its for an art project so it doesn't really matter. also i don't think we'd have internet connection which might be a problem.
     
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    That would be cool, but power is still an issue.

    And the traffic? None apparently. It's an art project in the forest.
     
  9. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Blue tooth or WIFI doesn't need an Internet connection, but might be a bit complex. IMHO.
     
  10. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    I gather that from your initial description and the fact that you are art students (and not EE students) that you are trying to combine off the shelf components.

    Do you have any electronics experience? Can you use a transistor as a switch? Do you have any programming experience? Have you coded a "Hello world" program or programmed an LED to flash? If we can get a better understanding of your skills, it will help in supplying a solution. If you need programming assistance, I've done that for art projects in the past.

    Your original idea is doable, with some possible consideration of the power and a small circuit to drive the LEDs. Do you know where in the forest your exhibit would be located? Would it be possible to locate the solar power unit in a clearing? How many days is the exhibit?

    We need the LED specifications in order to create a power budget. This will tell us over a 24 hour period, what the current draw will be. Then we can confirm if your solar panel would work over the exhibit time or if another alternative is needed. Wouldn't it be nice if all you require is a deep discharge battery! But we need those specs.

    I'd use an Arduino and put it to sleep when not in use overnight - low power mode. Shut off the LEDs too. The Arduino would serve as your traffic controller and timer both.

    Since all you would be sending through the 15M cable is power, you have a lot of leeway there as well. But we need to know the LED specs.

    And once again, I've reread your post and I'd recommend you doing some soldering.
     
  11. dock490

    Thread Starter New Member

    May 30, 2016
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    Yeah, after reading all of these things i've realised that we're both extremely under-qualified to do it ourselves. I'm currently trying to find someone else to do it for us and possibly find help within the university. If we find someone I'll pass over all of this information and see what they think. This has been really useful and has answered many questions. Thanks.
     
  12. eetech00

    Active Member

    Jun 8, 2013
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    yup...a little complex..

    Connect both raspis via bluetooth, or wifi, then write python program to perform logic and send commands between raspis.
    Use raspis GPIO as interface to LED drivers that connect to LED traffic lights.

    Power would still be an issue though..
     
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