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12 volt alternating flasher circuit?

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  • Member since
    July 2006
  • From: Bradford, Ontario
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12 volt alternating flasher circuit?
Posted by hon30critter on Friday, September 29, 2017 1:07 AM

Here I am again with another (dumb?) question.

The club has a railroad crossing display sign that uses 12 volt automotive bulbs. Unfortunately the power supply has croaked.

There are lots of 12 volt automotive alternating flasher units out there, some are cheap and some are fairly pricey. The problem with the cheap ones is that there is no way to adjust the flashing pattern to mimic a prototypical flashing pattern with the 'slow' lighting and darkening of the bulbs. There are also quite a few model railroad crossing signal flashers but nobody seems to offer a system that will use 12 volt bulbs.

We would like a prototypical flashing pattern without spending a lot of bucks.  If we can't get the prototypical pattern without spending a fortune, what are our alternatives? Any suggestions?

Thanks as always,

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
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Posted by gmpullman on Friday, September 29, 2017 1:44 AM

Hi, Dave

It's been a few years now but I've built a few of these, one for the old club I once belonged to and another for my brother-in-law that has a grade crossing signal in his back yard and another for myself for another grade crossing signal.

I'm driving (IIRC) 1156 auto lamps.

I used a Potter-Brumfield CNS-35-64 programmable time delay relay. The model I had on hand has a 120 VAC input voltage but the relay contacts will switch whatever you want to input.

It has a 10 amp 30 VDC DPDT (max) relay output. Timing range is 0.1 second to 100 minute timing range. There must be a similar relay available out there. I got these when they were tossing them out at work.

There is a seven place DIP switch to program any of eight functions. I just looked at Digikey and they show 0 available. 

https://www.digikey.com/product-detail/en/te-connectivity-potter-brumfield-relays/CNS-35-72/PB556-ND/678190

(Ouch!) I just saw one on Ebay... $150! I sure should have grabbed some more Sad they tossed out about a hundred of 'em.

I suppose you could take the output of one of the small LED type flashers and drive a solid-state relay with it?

[edit] Perhaps something like this would do the job.

http://www.ebay.com/itm/DC-12V-Multifunction-Self-lock-Relay-PLC-Cycle-Timer-Module-Delay-Time-Switch-/271958222133?epid=1056853731&hash=item3f51f92535:g:bRoAAOSws5pZMOC6

 

Anyway, this is how I made mine, maybe others will have some good ideas for you.

Good Luck, Ed

 

  • Member since
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  • From: Bradford, Ontario
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Posted by hon30critter on Friday, September 29, 2017 1:58 AM

Thanks Ed, I'll do some looking around. Not having to use a separate power supply is a bonus.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Friday, September 29, 2017 2:32 AM

And if you're not too much of a purist, you could use LED lamps with automotive sockets in your grade crossing signal. I have a few railroad signals in my yard and by replacing the incandescent auto lamps with LEDs I dropped the current draw from about ten amps to less than one.

Of course, you don't get the same "look" with LEDs, more like the present day ones. In my crossing signal I kept the original 10 volt lamps.

Good Luck, Ed

  • Member since
    April 2004
  • From: Ontario Canada
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Posted by Mark R. on Friday, September 29, 2017 8:11 PM

Don't know if this would work for you .... I have a set of crossing lights in my backyard and I got them to flash perfectly using an alternating flasher from a school bus ! Your local automotive parts supplier should be able to hook you up. 

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

  • Member since
    July 2006
  • From: Bradford, Ontario
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Posted by hon30critter on Friday, September 29, 2017 9:21 PM

Mark R.
I have a set of crossing lights in my backyard and I got them to flash perfectly using an alternating flasher from a school bus

Hi Mark,

That would definitely work but I don't think we want to spend the money on a commercial grade flashing unit. The heavy duty ones I have seen run about $60 Cdn. I have found cheaper ones on eBay but so far no Canadian suppliers. We are going to try Napa Auto Parts to see what they have.

Thanks for your suggestion.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Saturday, September 30, 2017 11:33 AM

Dave,

While most new police packages have factory installed lighting, some times they need to use a add on such as this near the bottom of the page:

http://www.superbrightbulbs.com/equalizers.htm

You will still need a power source but that should do it.

Their are circuits using a fan or lighting relay on the internet also:

https://www.youtube.com/watch?v=XVa0-R86Js0

Jim

  • Member since
    July 2006
  • From: Bradford, Ontario
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Posted by hon30critter on Sunday, October 1, 2017 9:17 PM

Problem solved!

The old flasher module has two knobs on it. When we first tried to adjust them nothing seemed to be working. However, one of our members decided to play around with the knobs and voila, he managed to get the flasher working. It turns out that the knobs have to be in very precise positions. If the knobs are even the slightest bit out of place nothing flashes, or it flashes very slowly.

So, problem solved for free!

Thanks everyone for your suggestions.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

  • Member since
    April 2004
  • From: Ontario Canada
  • 3,574 posts
Posted by Mark R. on Sunday, October 1, 2017 9:21 PM

hon30critter

Problem solved!

The old flasher module has two knobs on it. When we first tried to adjust them nothing seemed to be working. However, one of our members decided to play around with the knobs and voila, he managed to get the flasher working. It turns out that the knobs have to be in very precise positions. If the knobs are even the slightest bit out of place nothing flashes, or it flashes very slowly.

So, problem solved for free!

Thanks everyone for your suggestions.

Dave

 

I had a comment .... but I think I better keep it to myself ! Whistling

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

  • Member since
    July 2006
  • From: Bradford, Ontario
  • 15,797 posts
Posted by hon30critter on Sunday, October 1, 2017 10:54 PM

Jim:

Thanks for the lead on the flashing units.

Mark:

The guy who fixed it was the same guy who pronounced it dead in the first place.LaughLaugh Not sure if I should thank him for his perseverence or kick him in the butt for wasting everyone's time.Smile, Wink & Grin

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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