Pedestrian Crossing

Basic electrical and electronics, such as DC/Analog control.
JLK2707
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Pedestrian Crossing

Postby JLK2707 » Wed Aug 25, 2010 5:42 am

Hi, I am just wondering how I can make an HO Scale Pedestrian Crossing on a stripboard with a flashing green man symbol. Please help me with this. Regards, Jordan.

tuxychuff
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Re: Pedestrian Crossing

Postby tuxychuff » Sun Oct 03, 2010 4:29 pm

can you explain more about what you want?

traincrazy1
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Re: Pedestrian Crossing

Postby traincrazy1 » Fri Oct 29, 2010 10:52 pm

You probably want a monostable 555 circuit with the input connected to the button and the output, as well as cancelling the red light, going into either a much higher frequency 555 astable connected to an LED.
Actually, there's a bit where it's solid green before it starts to flash, so you could use an additional monostable with a shorter time period, triggered at the same time as the first and connected directly to the LED.
For a delay between pressing the button and starting to flash, you could use yet another monostable, wired such that both were activated simultaneously, but there was only an output if only one is on. E.g. if one had a 15-second period on, and the other had 10s, there would be a 10s pause, then a 5s output. (There might be an easier way, but it is 10:50pm :roll: ).
If you wanted road lights as well, that would be complicated and require me to do some thinking, which I'm trying to avoid for half-term 8) .
BTW, are you doing the AS tech course project in control electronics?

Good luck with whatever you do,
Francis
EDIT: Having seen your other thread, it appears I may have interpreted your query incorrectly :( .
To be clear, I was talking about these:http://www.google.co.uk/imgres?imgurl=http://www.coolmove.org.uk/image/upload/Imga0505.jpg&imgrefurl=http://www.coolmove.org.uk/good%2520pelican%2520guide.htm&usg=__x7S8ctJ2NidCMH35Lsi6ddSKjJA=&h=480&w=640&sz=56&hl=en&start=0&zoom=1&tbnid=GRvx24FWMbpZLM:&tbnh=134&tbnw=179&prev=/images%3Fq%3Dpelican%2Bcrossing%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DN%26rls%3Dorg.mozilla:en-GB:official%26biw%3D1024%26bih%3D586%26tbs%3Disch:10%2C57&um=1&itbs=1&iact=rc&dur=364&ei=AkXLTJH9A8ztObPI8I4B&oei=AkXLTJH9A8ztObPI8I4B&esq=1&page=1&ndsp=15&ved=1t:429,r:7,s:0&tx=63&ty=67&biw=1024&bih=586
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Peterm
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Re: Pedestrian Crossing

Postby Peterm » Sat Oct 30, 2010 3:34 am

Surely that's too simple. :wink:
Pete.

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Sat Oct 30, 2010 10:25 pm

I am just wondering how you can make a green or red LED flash on an HO Scale pedestrian crossing.

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Flashbang
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Re: Pedestrian Crossing

Postby Flashbang » Sat Oct 30, 2010 10:50 pm

JLK2707 wrote:I am just wondering how you can make a green or red LED flash on an HO Scale pedestrian crossing.

Turn on or off its supply at pre determined intervals!
You use an oscillator or monostable circuit to do this. This can be via a NE555 IC. Or even a NE556 dual IC etc
Try a Google search on 'NE555 circuits' and you'll see how an LED can be illuminated or flashed on/off etc.
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Broken? It was working correctly when I left it.

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Wed Nov 03, 2010 1:14 am

Is it possible to have this done with a 555 timer in which it flashes for a few seconds before going steady automatically?

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Flashbang
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Re: Pedestrian Crossing

Postby Flashbang » Wed Nov 03, 2010 12:01 pm

JLK2707 wrote:I am just wondering how you can make a green or red LED flash on an HO Scale pedestrian crossing.

JLK2707 wrote:Is it possible to have this done with a 555 timer in which it flashes for a few seconds before going steady automatically?

tuxychuff wrote:can you explain more about what you want?


So what exactly in detail do you want?
Both red and green flashing as per first request. Or one or both (red / green) flashing and then going steady as per your second post??

Please be more specific in the request of what the actual item is to display and roughly for how long. e.g. Steady green, changes to flashing green (or red?) then to a steady red after two seconds of green (or red) flashing etc.
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Broken? It was working correctly when I left it.

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Mon Nov 22, 2010 2:25 am

How do I make the following sequence using magnets and reed switches and 555 timers, LEDs, resistors, capacitators, etc. which are activated by approaching trains? Here it is:

Steady green going when no train is detected which changes to flashing red for four seconds after a train is detected before going steady red as the train approaches the crossing before cancelling the red until the next train arrives. I would also like to know how I can have the steady red stay on for extra time should another train be detected at a crossing with fourteen tracks along along with a flashing ANOTHER TRAIN COMING sign which would be displayed automatically by using a re-triggerable monostable circuit, triggered by the train sensors should there no opening of the crossing between successive trains.

Please help me asap.

Regards,

Jordan.
Last edited by JLK2707 on Thu Jan 06, 2011 12:02 pm, edited 3 times in total.

tuxychuff
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Re: Pedestrian Crossing

Postby tuxychuff » Mon Nov 22, 2010 8:43 pm

this what you were thinking?
screenshot2.png
screenshot2.png (12.24 KiB) Viewed 2775 times

three bistables
one monostable
one astable
screenshot3.png
screenshot3.png (11.87 KiB) Viewed 2774 times

three bistables
four monostables
one astable
I think

(555s can be both bistable, monostable and astable)
anyone with better understanding feel free to correct me! :)

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Thu Nov 25, 2010 11:12 am

Yes! This is what I had meant all along! Thank you so much for your help!

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Thu Nov 25, 2010 8:52 pm

How do I build this?

tuxychuff
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Re: Pedestrian Crossing

Postby tuxychuff » Thu Nov 25, 2010 9:26 pm

I personally don't quite understand 555s but I think when being used as timer they stop when an input voltage is the same as an output voltage.
when you know how to construct a astable, monosable and bistable you can wire them pretty directly from the flowcharts with a bit of thought. i.e. outputs to leds, inputs to inputs of each unit.
you could have: bistable "flashing on" outputting to monostable "flash"
you can probably get diagrams for each type of circuit on the web, google is your friend.
would try to be more help but don't have time (might at the weekend though)

you could try p.m.ing traincrazy1, I think he understands 555s

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Fri Nov 26, 2010 6:18 am

How many 555s would I need to build this project?

JLK2707
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Re: Pedestrian Crossing

Postby JLK2707 » Fri Nov 26, 2010 12:26 pm

Can anybody help me with how to build the following project:

Pedestrian Crossing.

How it will work:

The unit is often a green light for the traffic and a DON'T WALK for the pedestrians. But when a person presses the button at the side of the layout, the WAIT lamp illuminates. Then after a few seconds, the traffic lights then change to yellow and then to red and the WALK sign comes on. After the scale pedestrians have been given time to cross, the DON'T WALK sign starts to flash for four seconds before it goes steady. After four seconds, the traffic lights then switch on the yellow light along with the red before they change to green for the traffic.

The unit is often a green light for the traffic and a DON'T WALK for the pedestrians. But when a person presses the button at the side of the layout, the WAIT lamp illuminates. Then after a few seconds, the traffic lights then change to yellow and then to red and the WALK sign comes on. After the scale pedestrians have been given time to cross, the WALK sign starts to flash for four seconds before the DON'T WALK sign illuminates. After four seconds, the traffic lights then switch on the yellow light along with the red before they change to green for the traffic.

Any suggestions of how I can build this using 555 timers, a 4017 counter, BC547 Transistors, 1N4148 Diodes, etc.?


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