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That should work, but with one issue I can see.  With the issues I've heard about with alignment of the Lionel Acela IR link, I wonder how reliable it would be on curves, etc?  Also, you need a bit more logic wrapped around them to switch the lights, right?  The good side is that there's no interference with other consists, that's one issue to contend with with RF links.

Right.  As I said, this is a germinating thought.

So I cobbled together a simple experiment as shown in above video.  On the left is an IR LED (transmitter) driven by a nominal 20 mA.  This would represent what is transmitted by the powered car when the tail-light is ON.  On the right is a widget that I built some time in the last century which I use to detect the presence of Infrared (IR) energy.  I've written about it in previous OGR threads.  Basically, when IR energy is present the red LED turns ON.  The red LED gets brighter with more IR energy.  It is powered by a 9V (DC) battery.  The idea is this is essentially what would be the repeater circuitry in the intermediate/intervening cars.  When IR energy is detected from the previous car, the 25-cent circuit would repeat the tail-light on/off state via an IR LED (instead of the red LED) on the other end of the car to the next car.  And so on.

The experiment was to place the receiver about my guess of the distance between two subway cars....then to rotate the receiver to simulate going around curves.

The video suggests we're in the ball park!  I believe you can reliably detect the IR transmission from an adjacent car even going around curves.

As mentioned earlier, this only makes sense if already opening up the intermediate cars to convert from power-hungry bulbs to LEDs.  It is a very simple and inexpensive circuit to detect IR energy with an IR detector at one end of the car...and then re-transmit the on/off status to an IR LED at the other end of the car; this daisy-chains the on/off status of the tail-light to the end-car.  No "software" or fancy digital circuitry is required!

Last edited by stan2004

Looks promising, Stan, what happens if the receiver is off the axis of the transmitting lens?  I'm wondering how wide the beam angle is coming from the transmitter.  Your demo kept it right in line with the transmitter and only changed it's angle, just curious how far off-axis it can be and still see the beam.

Agreed my experiment was simply to see if in the ballpark.  This was one of those "raise the flag and see who salutes."

The LED and detector each have angular-displacement specifications.  In the case of the LED this characterizes how the intensity changes as you go off center (rotated).  Likewise for the detector, this characterizes how the sensitivity changes as you go off center.  For example, from the datasheet of one particular 3mm IR LED, the intensity is 90% if 10-degrees off center, and 80% if 20-degrees off center.

angular displacement

If this hobby project was "engineered," one should do-the-math to show if enough IR energy makes it across the gap going around an O-31 curve (or whatever the worst case curve is needed).  Likewise, to your point, the TX and RX devices will be slightly off-axis...this could be horizontal and/or vertical mis-alignment. For the matter at hand, I suggest an off-axis error can be converted to an off-center error and the parametric datasheet graphs can be used.

anglular equivalence

This is offered in the spirit of a discussion forum.  Again, this method would require modifying each car in the consist.  Hence, I commented that this would probably only make sense if already planning to open up the middle cars to, say, convert from bulbs to LEDs for the interior lights.

But if there's any interest in this method, even if only for discussion purposes, we can press forward.

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Last edited by stan2004
@MCD4x4 posted:

Hi John, how are did you make out with this project? I need forty of them.

All the different modules are actually all designed, prototyped, and tested.  It works great, and I've hand assembled a few of each of the components, even used several of them in my own stuff.  However, with the fall-off of interest for the summer, I haven't worked on getting any of it into production.  I'm at a crossroads with the project.

My dilemma is with very little feedback on what real quantities might be, committing to any volume production where I'd have a lot of money tied up in stock is a bit worrisome.  I've already gone down this road with my MP3 Sound board, after an initial flurry of interest, pretty much crickets.

What's the exact capability you are trying to achieve, is it simply handling directional lighting for the trailing cars?

I've already gone down this road with my MP3 Sound board, after an initial flurry of interest, pretty much crickets.

What's the exact capability you are trying to achieve, is it simply handling directional lighting for the trailing cars?

I don't know much about railroads and the need for directional lighting in a tail car but I can tell you that every Subway enthusiast that I talk to wants this addition to each one of their four, six and eight car sets.

What I'm looking for is this, the NYC MTH Subway's do not have tail lights. Some guys add them in and wire them to the ceiling lights, better than nothing. The engines have directional head and tail lights. I want that in the tail car. when changing directions the tail car would be opposite.

I also have few push pull trains I'd like to add the boards to. New Jersey Transit, Metro North etc. Like anything else I'm sure price would have a bearing on peoples buying habits. I myself need about fifty of them to be safe. How much would they cost singularly and in bulk?

Brian

Last edited by MCD4x4

We probably looking at something in the ballpark of $75 for the ability to control the directional lights on your trailing cars.  It involves a track powered transmitter in the head (powered) car monitoring the status of the headlight and/or reverse light output.  This status is transmitted back to the receiver in the rear car and controls the lighting.  This would allow directional markers and headlights.

4-Channel Transmitter

4-Channel Relay Receiver

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@MCD4x4 posted:

...

I'm about to swap all my NYC Subway cars over to LED's. probably about forty six car sets. I'd like to add head and tail lights to the last cars. The housings are there already. Only the LED's would have to be added. That's where my dilemma comes in.

'''

Curious if a ~$75 price tag is a buzzkill?  Let's see.  46 x $75 is a wad of Ben Franklin's!

Also, when you say swap "all...cars over to LEDs" does this also mean the incandescent interior lights?  I learned from one of your posts that the MTH Subway Cars have track-powered interior lights...including, as I understand it, the powered cars.

I don't have a Subway set and don't know "how" guys operate them.  But it seems that if one goes thru the effort of converting the tail-lights of Subway sets to LED, there would be interest in converting the interior lighting to LED too...and to also place those LEDs under DCS control assuming an available light outputs.

As I see it, you're trying to take a "universal" design and apply it to a very specific/narrow application.  Just wondering whether another tack is to flesh-out exactly what is needed/wanted for the specific application at hand.  Stated differently, so-called "universal" designs are great because they can be used in a wide variety of applications.  BUT.  They usually have everything but the kitchen sink and you're paying for it.  If you have an application that is specific enough that one person (i.e., YOU!) needs dozens of them, perhaps a different approach is warranted.  Just my 2 cents...

Last edited by stan2004

I'm pretty sure that was a major factor.

I have a ship in port, long days. Don't be so quick to judge, I'm interested but I would expect a discount on fifty boards. Two questions, why four channels for two lights, how big are these boards. I'd have to go back into notes but it doesn't look like its going to fit in the unseen area of a subway car. I remember posting a picture of the space I have. maybe you've worked on these before?



Brian NY

@MCD4x4 posted:

I have a ship in port, long days. Don't be so quick to judge

No judgment, just thought after three days I might have scared you away.

There's no way I can realistically judge if these would fit without actually seeing the cars.  I've seen various models of the subway cars before when working on them, but I don't keep all the clearances and details in my head as far as what might fit into them.  I know in standard passenger cars, my sense would be to stick these to the ceiling, I do that with LED lighting control modules. and they are out of sight unless you get below the window line and look up at an angle through the windows.

Considering the application, you could probably do the lighting with the FET receiver model.  It's 1.125"L x 1"W x .5"H.  The reason for two channels is independent control of two light channels.  The board come in 1 channel and 4 channel models, I don't happen to have a 2 channel board, but it wouldn't be much smaller than the 4 channel one.

The transmitter has a footprint of 1.4"L x 1.2"W x .4"H.

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Considering the application, you could probably do the lighting with the FET receiver model.  It's 1.125"L x 1"W x .5"H.  The reason for two channels is independent control of two light channels.  The board come in 1 channel and 4 channel models, I don't happen to have a 2 channel board, but it wouldn't be much smaller than the 4 channel one.

I was wrong, those dimensions are fine, they just looked big in the picture. The four channels gives me another idea. If there were two receivers, I'd be able to move the engine back into the third position and control the lights in the forward and last cars correct? That would leave the first and last cars empty and normal looking as apposed to not being able to see through them. Picture attached:



IMG_0642~photo

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Last edited by MCD4x4

Actually, since there are only two states for lights, you just need two channels for this option as well.  The two receivers both receive the transmitted signal, and just do the opposite thing with the lights.

Important point, the first two channels are microprocessor enhanced to allow additional lighting modes.  The last two channels just mirror the inputs as far as what is transmitted.  This is important as a continuous signal will inhibit other transmitters on other consists from operating if there is a continuous transmission.

GRJ, do the outputs of your FET (or relay output for that matter) receivers have provisioning to install a resistor for LED lighting?  And/or, stated differently, for this specific case of powering, say, a pair of directional LEDs, where does the low voltage DC come from (e.g., 5V DC) and how is current limited to the LEDs?  If you've already posted schematics in a previous thread and I've already made my comments on this, I apologize in advance for repeating myself.

mth subway

Brian, what am I looking at?  In YOUR photo on the right it appears there are seven (7) incandescent bulbs in sockets.  In YOUR photo on the left it appears there are seven (7) LEDs+resistor.  Is this the difference between PS2 and PS3?

Separately, in photo on left, there are two connectors circled in Orange and Purple.

The Orange connector appears to have 2 wires going to it, Orange+Purple.

The Purple connector appears to have 3 wires going to it, Purple+Green+Green.

My vision ain't so good but that's what it looks like - is this correct and what plugs into these connectors???

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Last edited by stan2004
@stan2004 posted:

GRJ, do the outputs of your FET (or relay output for that matter) receivers have provisioning to install a resistor for LED lighting?  And/or, stated differently, for this specific case of powering, say, a pair of directional LEDs, where does the low voltage DC come from (e.g., 5V DC) and how is current limited to the LEDs?  If you've already posted schematics in a previous thread and I've already made my comments on this, I apologize in advance for repeating myself.

I didn't put in provisions for optional resistors as the intent was a generic receiver.  Any resistors for LED use would be added externally.

Here's the documentation for the Universal Wireless Remote Controls Composite Documentation.pdf.

Here's an example of use of one of the remote receivers for controlling all aspects of the otherwise manually controlled Lionel sound cars.  This allows you to pick any combination of the sounds and also to turn power off to the sound board.

Click on graphic to enlarge.

Lionel Flat Wheel Sound Boxcar Remote Control

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Last edited by gunrunnerjohn

GRJ, I realize this is really peeling the layers of the onion.  I reviewed the documentation in your above post.  I want to confirm the "change" detector in the transmitter has a filter (software or hardware) to reject the kHz rate PWM lighting modulation on the PS2 and PS3 light signals.  Seems we had a discussion about this in some OGR thread and there might have been something about capacitors on the input circuit.  Fuzzy on the details.  That is, I did not see explicit mention in the documentation about such a filter to make it compatible with PS2/PS3 light outputs which of course is absolutely required for MTH Subway application.

Stan, each input to the transmitter goes through an AC opto-coupler and has a 1uf filter cap.  This filter cap allows me to accept 60hz AC, and of course, any higher frequency appearing on the input.  I connected one of the transmitter inputs to a PS/3 headlight output and it correctly identified the state.  The input voltage sensing range is from less than 2 volts to 18 volts AC or DC.

Here's what each input circuit looks like.  The diode is to isolate the RF transmit module input, some versions of the RF transmit module have cross-talk between the inputs.

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I'm still trying to understand EXACTLY what is needed for this application.  I'm still holding out for something special with INTERIOR LIGHT wireless control but that's just a peanut-gallery comment from a non-paying-customer!

I think it would be useful to draw out EXACTLY how the transmitter module hooks into a powered subway car including which connectors are used, where wires are spliced, etc. Likewise, EXACTLY how the receiver hooks into an end car, where external resistors must be added, etc..

For example, for the receiver, if all that is required is 2 white LEDs OR 2 red LEDs based on direction (i.e., never both ON together), I can imagine a scenario where this could be done with a 1-channel receiver.  That is, one output could use the "starve" the LED trick when employing 2 different LED colors.

@stan2004 posted:

I'm still trying to understand EXACTLY what is needed for this application.  I'm still holding out for something special with INTERIOR LIGHT wireless control but that's just a peanut-gallery comment from a non-paying-customer!

An exact set of requirements would be very useful, no doubt about it.

@stan2004 posted:

I think it would be useful to draw out EXACTLY how the transmitter module hooks into a powered subway car including which connectors are used, where wires are spliced, etc. Likewise, EXACTLY how the receiver hooks into an end car, where external resistors must be added, etc..

Those requirements would be useful for this activity.

@stan2004 posted:
For example, for the receiver, if all that is required is 2 white LEDs OR 2 red LEDs based on direction (i.e., never both ON together), I can imagine a scenario where this could be done with a 1-channel receiver.  That is, one output could use the "starve" the LED trick when employing 2 different LED colors.

No need for the "starve" voltage trick, the 1-channel relay receiver has two sets of Form-C contacts, plenty to do this the classic way.

@stan2004 posted:

mth subway

Brian, what am I looking at?  In YOUR photo on the right it appears there are seven (7) incandescent bulbs in sockets.  In YOUR photo on the left it appears there are seven (7) LEDs+resistor.  Is this the difference between PS2 and PS3?

Separately, in photo on left, there are two connectors circled in Orange and Purple.

The Orange connector appears to have 2 wires going to it, Orange+Purple.

The Purple connector appears to have 3 wires going to it, Purple+Green+Green.

My vision ain't so good but that's what it looks like - is this correct and what plugs into these connectors???

Stan,

The two pictures you post are of the same PS2 Subway engine. The Subway engines, and all trailer cars power the interior lights off of track power, same thing with PS3. The picture on the left is after I swapped out the glass power sucking bulb for some LED's with  resistors to lower the voltage.

The empty connectors you see are from the body mounted head/tail or marker lights.

Actually, since there are only two states for lights, you just need two channels for this option as well.  The two receivers both receive the transmitted signal, and just do the opposite thing with the lights.

Important point, the first two channels are microprocessor enhanced to allow additional lighting modes.  The last two channels just mirror the inputs as far as what is transmitted.  This is important as a continuous signal will inhibit other trs tansmitters on other consists from operating if there is a continuous transmission.

John with no electronics in the trailer cars I'm assuming your boards would be track powered and as such protected or regulated if the trans former is all the way up?

Also, if there were multiple trains running, would the transmitters interfere with each other, changing lights on different train?



Brian NY

@MCD4x4 posted:

John with no electronics in the trailer cars I'm assuming your boards would be track powered and as such protected or regulated if the trans former is all the way up?

Also, if there were multiple trains running, would the transmitters interfere with each other, changing lights on different train?



Brian NY

Correct, they boards are designed to run on track power and to not interfere with DCS track signals.  The transmitters are also designed not to step on each other.  The first two transmit channels are micro-processor controlled to prevent them from continuous transmission and stepping on other signals from other transmitters.

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