Hi! Like many boys my son is obsessed with trains and has asked if we could build a train gate together (aka train crossing) in his room. I'm handy, so the bulk of the project won't be a problem, but I'm not sure how to wire the lights. I was thinking of purchasing the two of the lights from Ali express below, and I'm assuming I could use some 12V DC converter from some old piece of electronics as a power source. However, I'm not sure how to make the two lights alternate back and forth. Most of the wiring diagrams I've seen seem to be for very small projects or individual LEDs, so I"m not sure if they'd work. I appreciate your thoughts and suggestions.

https://www.aliexpress.com/item/2251832623667312.html?spm=a2g0o.cart.0.0.230d38daD9qcIy&mp=1

 

Here's a 555 circuit with transistors to drive the LEDs. From the specs listed from your link I believe the current draw is 160ma for each LED.
VR1 is to adjust the flashing rate.

 

Welcome to AAC.

I think the easiest possible way would be to use an automotive flasher with a SPDT (Single Pole Double Throw) relay. The flasher is a specialized relay which (traditionally, and in most current cases) uses a bimetallic spring the is heated by a resistor when power is applied.

When the spring snaps over, it cuts off the power to the resistor as well as to the load, then it cools, and snaps back starting the cycle over. It only does one thing, blink, but if you wire that to a SPDT relay’s coil, and one light to the NO (Normally Open) contact, the other to NC (Normally Closed), with the 12V supply to the common terminal, they will alternate.

The downside of this arrangement is that you will have no control over the speed of the flashing, though it would probably be a reasonable one. It would make a satisfying clicking noise, which is a bonus in a case like this.

 

While not the cheapest module, this will do it as is, and it has an adjustable duty cycle which is a nice thing for you application.

Here’s a video: https://www.amazon.com/vdp/0e021f3a...B00XM10ON2&ref=cm_sw_em_r_ib_dt_kt3SK1IOjq0O4

 

From the link in #5:
http://www.555-timer-circuits.com/flashing-railroad-lights.html

 

From the link in #5:
http://www.555-timer-circuits.com/flashing-railroad-lights.html

Will need transistors to drive the LEDs as I show in post #1 if the TS uses the LEDs he posted a link to.

 

That LED is high power and quite bright.
Do you need that much for a model train crossing light?

 

That LED is high power and quite bright.
Do you need that much for a model train crossing light?

It is my impression this is going to be a standalone, similar-to-full-scale affair.

 

The scheme in post #2 could work, but I did see that the current was given as 160 mA. So transistor heating will be a problem with those 2N2222 transistors. I am guessing that this flasher gate will be on for extended periods of time.

 

So transistor heating will be a problem with those 2N2222 transistors.

Non issue. With the 1K base resistors the saturation voltage of the 2N2222 is appx 120mv. Dissipation is only 19mw with a 50% duty cycle.

 

Search for " 1X Compact Circuit Board Flasher to Flash Crossing Signals Alternately PCB006" on eBay and use as starting point.

 

Wow, Im blown away at all the suggestions everyone, thank you. I will read your suggestions, make a call, and post the result once it's done!! THANK YOU!

P.S. Yes, this is supposed to be more near-life size as it will be floor-to-ceiling standing in his room.

 

Hi! Like many boys my son is obsessed with trains and has asked if we could build a train gate together (aka train crossing) in his room. I'm handy, so the bulk of the project won't be a problem, but I'm not sure how to wire the lights. I was thinking of purchasing the two of the lights from Ali express below, and I'm assuming I could use some 12V DC converter from some old piece of electronics as a power source. However, I'm not sure how to make the two lights alternate back and forth. Most of the wiring diagrams I've seen seem to be for very small projects or individual LEDs, so I"m not sure if they'd work. I appreciate your thoughts and suggestions.

https://www.aliexpress.com/item/2251832623667312.html?spm=a2g0o.cart.0.0.230d38daD9qcIy&mp=1

I just wanted to say thanks to you all. Attached is our finished project, and my son absolutely loves it! We ended up going with the PCB006 circuit board on eBay 'cause it was cheap and simple. The first was a dud, but they sent me a second one and it works perfectly. Thank you so much for all of your great suggestions and helping us!

 

I just wanted to say thanks to you all. Attached is our finished project, and my son absolutely loves it! We ended up going with the PCB006 circuit board on eBay 'cause it was cheap and simple. The first was a dud, but they sent me a second one and it works perfectly. Thank you so much for all of your great suggestions and helping us!

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Your last post makes everything in this forum worth it.

Ron