LED signal with Lionel 153ir

Yellow over red would be appropriate for approach diverging.

John, how could they have wired the leds to prevent lighting the green over red lights at once? They only show one light lit at a time.

From the eBay link attached.

This also in talks of a modern subway signal, not the usual railroading signal system. Im pretty you know how the subway signal system works? A simple 3 light LED signal to resemble a subway signal.

By secondary indicator I believe GRJ is referring to the question about the 2-head signal by OG3RAIL post.

Do you really need the 3 sec delay from Red-to-Yellow after the train clears the sensor?  After all, this time delay as well as the Yellow-to-Green delay is a simulation for convenience rather than wiring up more block-occupancy sensors. 

If you can live with Red-to-Yellow as soon as the train clears the sensor, I think I can come up with a very simple ITAD stand-in for the schematic I showed earlier using the 555 chip.  You'd still have the Yellow-to-Green time delay of 3 seconds or whatever you want. 

Would an Infrared (IR) LED shooting a beam across the track to an IR photo-transistor work in your layout as the sensor?

I'm talking about this.

John,

Some railroads use that combination. It fits in with FRA regs and GCOR rules. Look at the third attachment to my last response.

The two head light is for a switch signal like a dwarf on the mast. The attachment above shows some combinations used.

He cannot get green(top) and red(bottom) to light, which would be clear to next signal, no switching coming. He gets yellow(top) and red(bottom) which is medium speed to next signal, may be switching.

I don't have any of those two-head ones, but I had no issues getting the single head one to function properly.

I'm sure there's a way, perhaps they're reversed polarity to light those?  I'd have to have one and just test it on the bench to see how all the lights are wired.  The description doesn't seem accurate, they have duplicate descriptions for wires.

Well, that's what I didn't know, when they noted cathode as a term. He gets yellow top and red bottom, so why not green top and red bottom?

So, power to the single wire and ground to the light leads?

The other signals are common anode, so the positive goes to the lead with the resistor, and then negative goes to the various LED cathodes connected to the other wires.  I don't know how they wired the dual head models, there should be a total of six wires if all the LED's are separately controlled.

These 3 Aspects RR Signals are the ones I have, they work exactly as you'd expect.  I also have the dwarf signals, also wired logically.

with mine if you wire green to light up direct to a power source then wire up the red to a insulated rail block  when the red kicks on it turns the green off. mine are the same ones john has. I can have yellow and green on at the same time and red and yellow on at the same time but not green and red. I don't know enough about electricity to understand it but it's acts like the red shorts out the green to turn it off when lit up I can wire them up as a red and green 2 aspect signal without any relays. if I want the yellow to work I can use a relay to do the switching for yellow and red green I just power direct to a power source. 1 single spdt relay. when the red is on via the relay it also powers the previous signal's yellow. here's a video of mine being tested the night I got them hooked up. towards the end of the video one signal stayed red it turned out the track was making the connection between two blocks that's why it stayed red.

Oops! It's a 1 1/2 year old post and he never replied. Oh well, it was fun.

Anyway, it's a yard or junction approach signal.

Thats the signal I want to use. a 3 aspect R/Y/G. The ebay seller has the logic relay pre built and ready to sell, but im just trying to build my own logic really system. (If thats what its called) I tried looking for circuit diagrams everywhere But I cant seem to find them. I've seen members here build there own, would love it if you guys could share it. THank you!

Did you look at the whole thread?  This was posted earlier by stan0004.

As you can see, one chip and one transistor and you have the timed yellow, and no clickity-clack.

shipment from china 10 day to show up at the door

I guess my next product needs to be a cheap signal circuit.

Sounds Good!

GRJohn and Dale - have you thought about going the Arduino route for this?  I'm not sure how the costs compare - last time I looked the Arduino Uno is around $20 (+/- $5).  There are relay 'shields' that couple directly to the Uno board, which seem to be in the neighborhood of $15 and up, depending on the number of relays involved.  Probably need an external power supply, dropping resistors for LEDs, etc. (likely would need these anyway).

Seems to me the big advantage of this approach is the total flexibility of the system - both in terms of reading various inputs (e.g. IR-based photodetection) and the control of the outputs - timing, delay, relays for lights, crossing gates, powering track blocks, etc.  As you might guess, there's a lot of this sort of 'stuff' out there already (Google Arduino and model railroads as a place to start) - both hardware designs and Arduino sketches (programs).  You can also multiplex inputs and outputs, so (in principle) one Arduino can control a number of functions on a layout...

- Rich

Ill probably use this diagram. Do you think you can post up some of the pieces you have to buy on Ebay? Thanks

I suspect I could whack a PIC based board together to do this for a couple of dollars in parts.  I'm guessing that the total cost in any kind of quantity to build it would be in the $4-5 range.  Obviously, to sell them you'd have to get more, but they would certainly not be expensive.  The 8-pin PIC costs less than a buck, and if you shop for the cheapest model, probably more like 50 cents.

If you wanted the option to drive incandescent lights, a 20 cent FET on each output will give you several amps of drive current.

The trick here would be doing a board that's universal enough to do a variety of functions with different code.

I suggest Digkey for parts, cheap and very cheap shipping. 

NE555, and the 2N3904 is even cheaper.  The resistors are a couple of cents, and the small capacitors are cheap as well.

While you're at it, make a very small DC supply so you can power this from track power.

If you're just making 1 unit and are chomping at the bit to get started, definitely consider DigiKey as GRJ suggets.  Here's a cheap matching pair of IR transmitter (LED) and receiver/detector (phototransistor) I found on DigiKey at 26 cents and 38 cents each.  If links don't work as GRJ reports below, search DigiKey site for: 

WP710A10F3C (LED) and LTR-4206E (photo transistor).

Both devices are the 3mm style which is apparently what WeHonest uses also.

If you're making more than 1 signal set, or plan to do additional DIY electronic projects, here are some eBay type pricing for various items:

555 timer IC:  10 for 99 cents free shipping

2N3904 transistor: 30 for 99 cents free shipping

3mm IR LED and phototransistors: 10 pairs for $2.99 free shipping

And for the resistors, I'd get a resistor assortment:

400 resistors (20 each of 20 common values including all I used in the schematic): $2.21 free shipping or about 1/2 cent each which is a great price.

Stan, your Digikey links don't work.

I had my heart set on the Atlas signal system for my layout. Now you folks are ruining that with all these electronic projects I have a terrible weakness for. 

Looks like some very interesting info here though and I do enjoy reading it. I lean toward the 555 timers, Arduino and PIC stuff, but I also enjoy Dale H's relay circuits. There is a lot that can be learned there with relays as well.

In the latest Garden Railways magazine, there is an article about crossing signals using the PIC chips, just a FYI. Wish OGR would start up a regular electronics/electrical info and project type column. 

Thanks Stan! Now in the diagram, I can see its powered by A 12 Volt DC adapter. Do you know where I can find these Adapters? Can I also daisy chain it? And The leds wont pop if they have a maximum current of 3 volts/ 20ma? Also what part should I change if I wanna make the delay from red to yellow longer? in the video it looks instantaneous, Which isn't prototypical. It looks like you used something to hold the receiver, Do you know what it is, the blue cable? Thanks again

I've bought stuff from Wehonest before and shipping usually takes about a week to ten days. Pretty good considering the distance.

eBay has 12V DC, 1 Amp adapters for about $2 shipped


As shown in the inset you can separately buy a power jack adapter to convert the coaxial connection to screw-terminals if you don't want to cut the cable and strip wires.  Since this adapter supplies 1 Amp, you can daisy-chain at least ten signals as each circuit requires less than 0.1 Amp.

Or if you have 14-16VAC accessory power, or are running command mode 18VAC and have continuous track voltage you can build your own circuit to generate 12V DC.  If you go this route it's probably simpler to buy an eBay DC-DC voltage regulator module for about $1 and a bridge rectifier to do the AC-DC conversion.  Search OGR for "LM2596" for articles on how to do this.

The R-Y-G LEDs use essentially the same circuit as MTH does in their 3-aspect signal head - that was a starting point of this sub-topic.  The 1K resistor limits the current into the R Y or G LED.  Only one LED is on at a time and even if one of the LEDs was shorted the current would be limited to 12V / 1K ohms or 12mA.  The IR LED transmitter is of course an LED itself.  Actually an IR LED has a lower operating voltage than colored LEDs.  When you say 3V, you might be thinking a white LED which typically runs about 3V at 20mA.  For the same current, G usually runs at little lower voltage, Y and R run a little lower still (around 2V) and IR runs the least at maybe 1.2V.  And a regular non-LED diode runs at about 0.6V.

As mentioned earlier in the thread there is 0 delay from R-Y.  Again, these delays are not prototypical in the first place.  To be prototypical don't you need multiple block-occupancy sensors?  Think of the case where the train clears the sensor and immediately stops.  With your proposed delay it would go R-Y in 3 sec, then Y-G in 3 sec.  Well, I wouldn't want to ride a subway that used that kind of signaling!  I think that's called a train-wreck.  As others have mentioned there are other signaling circuits that have multiple sensors that don't assume the train is moving and truly detect that the track is "clear" before changing color.

No the blue cable is just colored wire.  You will need to fabricate some kind of housing or hide the IR LED and IR photo-transistor.  If you ask I'm sure some guys will post photos of how they disguise track-side sensors.

I like that little adapter Stan, do you have a link for that?

Here's one on eBay for 99 cents shipped and you get one female and one male.

Thanks Stan, I'm on it.

Dale, you're working overtime to eliminate electronics from the picture!

Guys I dont know if'ts OK, to go back to the LED,Signal , that Carl (mooman)

posted on the 1st page.  I took off and now have a pair of these,  I would like

to run them like the Lionel signal bridge,  ( assume put the like colors together)

and send the Black off to power,  BUT, BUT, there is that YELLOW, wire, is there

a way to bring that yellow light on, before, the signal changes,  thanks, ( if i need

to move posting and start thread, I can !!!!!!!!!!!!  I just see Dale and John helping

here, Thanks

Yes, the ITAD references are just connection points from the original circuit where an actual MTH ITAD was used for the infrared sensing.  The ITAD functionality is essentially replaced by the components to the left of those ITAD references albeit the circuit is shooting a beam across the track rather than reflecting a beam off the passing train.

If you're desperate I see Radio Shack sells 10uF 35V capacitors for $1.49.

I'd still get 10 uF capacitors as they are a common value to keep around.  In the mean time, if part of your objective is to learn about the 555 chip, you can "play" with the product of R1 x C1.  As shown, R1=1M and C1=10 uF, so R1 x C1 = 10 seconds.  That's about the yellow time delay.  Did you buy the resistor kit suggested?  If all you have is a 220 uF capacitor you could change R1 to 10K so that R1 x C1 is 2.2 seconds.  I think you wanted something closer to 3 seconds for the yellow delay anyway.

You can use 220 uF for C2.

Brought all the pieces you showed me. I see so I can lower the resistance of R1 to get away with the 220 uf capacitor? Sounds good. Also I may just use this configuration for power.

I have a Lionel CW80 which gives about 18 VAC in the accessory power output terminals. So I was thinking of using a single Diode for the + Wire, Put it into a DC-DC module convter (LM2596 I believe) With the LED, set output to 12 volts.

Using a single-diode to convert AC-DC can work in specific situations but for a general purpose DC power source where you may be adding additional signal circuits or who knows what, I recommend using a bridge rectifier or 4-diodes wired up as a bridge.  In basic terms you will have more available power.

It appears you have some single-diodes - perhaps from eBay where they are 4 cents (25 for 99 cents free shipping).  So taking a few extra minutes to wire up 4 diodes as a bridge is worth it.   Of course if you already have a bridge rectifier lying around use that. 

Here are some re-cycled photos of a $1 eBay LM2596 DC-DC module with a bridge-rectifier or 4-diodes on the input.  If you don't know how to connect 4-diodes as a bridge, just google the terms or ask!

Correct.  The 2 ~ squiggly lines are the AC inputs that are interchangeable in terms of which ~ you hook to your transformer's 2 accessory AC voltage jacks.

i probably should have asked  this, how should I set up the transistor? I dont know how to link it to the diagram.

By transistor do you mean the photo-transistor or the 2N3904?  And by link do you mean which pin on the package corresponds to the symbol on the drawing?

I know the 2n3904 transistor has a base collector and emitter But I dont know how to find it on the transistor and link it to the diagram. LIke I know the NPN symbol but I dont know which side is the base Emitter and collecter

No problem.  Usually if you know a part number like "2N3904" just google it and you'll find an image - often from a manufacturer datasheet - that shows you what you're looking for.  Here's one of the first images that popped up from google: