Traffic light Project

[KageKiyo]

Hi
Im currently working on a traffic light project at university and would like some ideas/advice on how to go about doing it.
You can view the specification of the project from the following url :
**broken link removed**

My part of the design is "PART 4: The traffic lights" of the document.

Im thinking about using opto-isolator to seperate my part of the design and a triac to control the intensity of the lights. We are not allowed to use any programable logic devices .

Any suggestions would be appreciated.

 

[eblc1388]

Normal opto-isolator are for DC only.

Take a look at the data sheet of opto-isolated TRIAC MOC3020, which can be used as a driver to drive a power TRIAC for the lamp bulbs.

It needs 30mA DC to switch on so can be driven by a small transistor using the traffic light logic output.

With suitable AC zero crossing detector, logic gatings and monostable one can control the ON/OFF and intensity of the AC lamp bulb.

 

[KageKiyo]

I was told to use an opto-isoltor/optocoupler to seperate the low voltage part of the circuit from the high voltage i.e the logic circuit from the traffic lights.
I also need to use a diac/triac to control the intensity of the bulbs and a timer.
Can anyone please provide me with a schematic of this since this is my first design course and im totally confused!!!

 

[Hero999]

Here's a simple phase control dimmer I designed just as an intellectual challenge awhile ago. I'm sure it will work but I haven't built it and the values of certain components still need calculating but I'll leave that up to you.

Once you've learnt about phase control dimming it should be easy to figure out how this circuit works, but Google should be able to help you with that.

https://www.google.com/search?num=1...se++control+dimmer+tutorial+triac&btnG=Search
https://www.hobbyprojects.com/thyristor_triac_and_diac/phase_triggering_the_thyristor.html
https://www.opamp-electronics.com/tutorials/the_triac_3_07_06.htm
**broken link removed**

 

[hasi93]

plz anyone help.am doing a project on intelligent traffic control.my idea is to switch the traf
fic light on the basis of rush.but iam stuck with 'how to sense vehichle?'

 

[Vikky]

Place the IR LED in the path at a regular distance equal or little bit longer to then length of the car. Place the photodiode near the LED to received the reflected signals.

Now when their will be no car infront of the IR LED, their would not be any reflections of the waves. But when their is any thing comes in front of LED, their will occur a reflection. Collecting these reflected waves through photodiode will change the collector voltage of it.

By counting the nos. of photodiode whose collector voltage as changed you can judge the no. of vehicle at that particular path.

The other tedious method what has been employed on the London Street is the counting the speed of the vehicle. If their is no traffic the vehicle will able to travel at high speed compared to moving in the crowded place.
For this they have again used the IR LED - photodiode only, but they also measure after how much time the second photodiode placed at some distance gets change in its state after the first one has changed.

 

[hasi93]

but wot happns when heavy vehicls come?