Best Of Pennsy Position-Light Signal Head - Shapeways Project?

[wazzou]

Or if you're really serious about it and you seem to have some people willing to pay you for your efforts, send the file to a place that prints in a very fine resolution.  Maybe Bryan Bussey will chime in with the name of a good place. 
If you make castings, my advice is always to make the best possible master to mold and then make another of one of your 1st generation castings to have as a backup.

[VonRyan]

These are excellent signals.

One thing to look at is having the heads printed without the rear bracket for use with signal bridges. By having it printed that way, it would prevent someone from damaging the printing for the LEDs if there were to just go ahead and cut off the bracket.



-Cody F.

[Dave V]

These are excellent signals.

One thing to look at is having the heads printed without the rear bracket for use with signal bridges. By having it printed that way, it would prevent someone from damaging the printing for the LEDs if there were to just go ahead and cut off the bracket.



-Cody F.

I'm guessing you would buy the heads and the LEDs separately.

Traincat and Alkem have options for mast and bridge mounts.

[VonRyan]

I'm guessing you would buy the heads and the LEDs separately.

Traincat and Alkem have options for mast and bridge mounts.

Yes. With the amount of magnet wire coming off the back of the heads (which for a mast-mounted signal head isn't a problem), I'd be looking towards a way to perhaps scratchbuild my own bridge, or modify one, so that the wires become more camouflaged.



-Cody F.

[delamaize]

Yes. With the amount of magnet wire coming off the back of the heads (which for a mast-mounted signal head isn't a problem), I'd be looking towards a way to perhaps scratchbuild my own bridge, or modify one, so that the wires become more camouflaged.



-Cody F.

can you wire them to a common ground and save a few wires?

[Dave V]

can you wire them to a common ground and save a few wires?

Yes...  That's how the Alkem pre-wired heads come.

[peteski]

Here is a diagram showing how to reduce the rat's nest of wires. 



It is much easier to stuff 5 rather than 14 wires down the mast. If the mast is brass, it can be used for the common lead. That would reduce the wire count down to 4.

Since the center LED is by itself and the rest are wired in pairs (in series), the resistor value for the center LED will have to be different from the rest so that the brightness of all the LEDs matches.   This is shown wired for common anode (common positive). Common is the orange wire. To make this signal common-cathode just flip the LEDs 180 degrees.

The routing of the wires in the diagram was chosen to make the drawing as clearer.  If the wire is insulated (like magnet wire), the wires can easily be crossed.  I think the best way to wire the LEDs would be in some sort of a jig. Then take the LED/wire assembly and glue the LEDs into the target.

If I was to build this circuit, I would use uninsulated tinned wire for ease of soldering.  The only insulated (magnet) wire would be used for the leads going down the mast.  I make my own bare tinned wire but taking a single strand from ordinary lamp cord. I then dip it in flux and then run it through a bead of solder on the tip of my soldering iron. That tins the wire nicely.  Tinned wire solders very easily. That speed is very important when soldering wire to SMD LEDs.

My other comment it about the printing orientation. From what I understand about the printing process, the best quality is achieved if the resin is not printed over a layer of supporting wax. This means that for the best quality, the front of the signal should be facing up and be the very top printout done on the tray.

[John]

I use the traincat signals, .. to get rid of the extra wire, I solder one side of the LED to the signal head .. which is also connected to the mast .. of course, those are brass heads ...

[VonRyan]

Here is a diagram showing how to reduce the rat's nest of wires. 



It is much easier to stuff 5 rather than 14 wires down the mast. If the mast is brass, it can be used for the common lead. That would reduce the wire count down to 4.

Since the center LED is by itself and the rest are wired in pairs (in series), the resistor value for the center LED will have to be different from the rest so that the brightness of all the LEDs matches.   This is shown wired for common anode (common positive). Common is the orange wire. To make this signal common-cathode just flip the LEDs 180 degrees.

The routing of the wires in the diagram was chosen to make the drawing as clearer.  If the wire is insulated (like magnet wire), the wires can easily be crossed.  I think the best way to wire the LEDs would be in some sort of a jig. Then take the LED/wire assembly and glue the LEDs into the target.

If I was to build this circuit, I would use uninsulated tinned wire for ease of soldering.  The only insulated (magnet) wire would be used for the leads going down the mast.  I make my own bare tinned wire but taking a single strand from ordinary lamp cord. I then dip it in flux and then run it through a bead of solder on the tip of my soldering iron. That tins the wire nicely.  Tinned wire solders very easily. That speed is very important when soldering wire to SMD LEDs.

My other comment it about the printing orientation. From what I understand about the printing process, the best quality is achieved if the resin is not printed over a layer of supporting wax. This means that for the best quality, the front of the signal should be facing up and be the very top printout done on the tray.

That'll do it.

That means just 20 leads for a 4 track signal bridge.


-Cody F.

[DKS]

That'll do it.

That means just 20 leads for a 4 track signal bridge.


-Cody F.

Actually, you can drop it down to 14. All of the anodes can be wired together; also, all of the center lights can be wired together, since they never change.

[VonRyan]

Actually, you can drop it down to 14. All of the anodes can be wired together; also, all of the center lights can be wired together, since they never change.

True. I should have thought of that.
Of course, it would still be an interesting task to hide all 14 leads on that signal bridge...


-Cody F.

[peteski]

True. I should have thought of that.
Of course, it would still be an interesting task to hide all 14 leads on that signal bridge...


-Cody F.

It is not my problem that the railroad you chose to model used multi-bulb signals which emulated semaphores and main lines with more than 2 tracks! 

Seriously, since the LEDs will most likely not consume more than 0.01 Amps (10mA) in each circuit, you can get away with using the smallest magnet wire you can find.  Even 14 leads can be easily hidden.

[Ed Kapuscinski]

There was a guy who had a full 3 track signal bridge at the last Bedford show. It was pornographic. He said he had something like $300 worth of hardware on it.

You're lucky in that there's often a lot of conduit and cabling on the real things too.

And I'm glad I model a mostly single and double track former PRR line... Eric's in trouble though.

[VonRyan]

It is not my problem that the railroad you chose to model used multi-bulb signals which emulated semaphores and main lines with more than 2 tracks! 

Seriously, since the LEDs will most likely not consume more than 0.01 Amps (10mA) in each circuit, you can get away with using the smallest magnet wire you can find.  Even 14 leads can be easily hidden.

Challenge accepted.

There was a guy who had a full 3 track signal bridge at the last Bedford show. It was pornographic. He said he had something like $300 worth of hardware on it.

You're lucky in that there's often a lot of conduit and cabling on the real things too.

And I'm glad I model a mostly single and double track former PRR line... Eric's in trouble though.

Of course, since I was on a cruise and couldn't be there...

At least my HCD layout is an industrial line, so no signals.
Though, seeing as how it would be cool for the heck of it, I might give it a go to at least see if it can be done for under $300. (which if the guy used fancy electronics, my own build will already cost less)


-Cody F.

[peteski]

I just re-read DKS' lead reduction proposal and if I understand it correctly he proposes to have single negative lead for all the center LEDs.  While it should be ok to hook up 4 identical LEDs (from the same production lot) to be connected in parallel and share a singe current limiting resistor, I personally don't like doing that.

I would install a separate resistor for each center LED. Those could be hidden either on the target or on the bridge. That way single negative lead can still feed all 4 center LEDs with their own current limiting resistors.  I know that I'm being overly conservative in my design, but that's just how I am.