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Discussion Starter #1
... with PS/2 (5v).

If I'm pulling a heavy train up a steep incline and have a 100% duty cycle (assuming that the motors are PWM controlled), what is the resulting DC voltage that my motor sees? I consulted the all knowing Google and didn't find the answer. I'm hoping one of our resident MTH service techs knows the answer.

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I have an idea. If it works, I'll have a double headed 2-8-0 freight train running from a single PS/2 board, for far less $$ than a PS/32 kit.

Using the PS1 2-8-0 that I accidentally bought and an Arduino, it will have simple sounds (startup, idle, flywheel controlled chuff, shutdown). I can even sync the smoke to the chuff. I may even be able to do a brake sound (if the duty cycle drops more than X over Y period of time). I'm going to aim for the 1st 4 sounds and chuff. Braking sounds will be icing on the cake.

I know I will need a front coupler somewhere, but I'm going to wait until the test circuit works before I start "kit-bashing".

If it fails, it will most likely simply not work. If it fails BADLY, I will have another locomotive in need of a PS/32 board. Being that it's a 5v board, it's a gamble that I'm willing to take.

I'll draw up the schematic shortly and post it. BUT I need the original question answered first so I know what I need to design.
 

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I don’t know the answer to your question, but I do know that a PS2 or PS3 board will run 2 can motors in a diesel (or a compound/duplex steamer). Both of your locos have the same motors and gearing?
 

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Are the engines Railkings? If so each one likely has a Mabuchi RS385. It would the same as a Diesel with two of these motors. As long as the gearing and driver diameter is the same there should be no problem.
If each one has a Pittman than it may be a little more chancey.

Pete
 

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Discussion Starter #4
I don’t know the answer to your question, but I do know that a PS2 or PS3 board will run 2 can motors in a diesel (or a compound/duplex steamer). Both of your locos have the same motors and gearing?
So if I understand you guys correctly, I can extend the motor wires to the motor in the 2nd loco without blowing out the PS/2 board, correct?

That will make my circuit WAY simpler. I was planning to use an LM1875 to drive the motor in the 2nd loco, but if I can drive it directly from the master PS/2 board, that would be AWESOME!!! And yes, they both have can motors. They are all but the same loco with different control boards.
 

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Both Railking and Premier use can motors but Premiers are bigger and may tax the board. The smaller motors in the Railking engines would be OK just wired in parallel. No intermediate circuit needed.
What are the items numbers for the engines?

Pete
 

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Discussion Starter #6
Both Railking and Premier use can motors but Premiers are bigger and may tax the board. The smaller motors in the Railking engines would be OK just wired in parallel. No intermediate circuit needed.
What are the items numbers for the engines?

Pete
They are both Railking.
Master: 30-1309-1
Slave: 30-1159-0
 

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The electronics will be fine. It would be a good idea to verify the gear ratio is the same. Just pull off the shells and turn the flywheel and count to turns required for one wheel rotation.

Pete
 

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Discussion Starter #8
Gear ratio 28:1 on both. Alligator clip lead test - IT WORKS. Now, how to route the wire discretely? To make my plan work, I need a minimum of 3 conductors:
  1. Motor +
  2. Motor -
  3. Light ( will be used to trigger the startup and shutdown audio sequences)
Smoke, chuff and other audio will be controlled by the slave. The only thing that the master will control directly is the motor speed.

This is going to be fun.
 

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One suggestion is a 3-conductor JST connector pair. They come in a myriad of sizes. The JST XM 2.54 mm pitch is manageable for normal fingers. They're all over eBay for low cost. But they ship on the "slow boat from China." 3+ weeks. But ensure the pigtails are 22 AWG wire. Lots of offers have 26 AWG. And that's a little light for motors. Even with the short run.

And if you don't like the coloring, that's what sharpies are for (what I did).

JST.png
 

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Discussion Starter #10
Ok, update AND QUESTION.....

1st the question:
What does MTH modulate to sync the smoke with the wheels, the fan speed or the smoke heater element?

Now the update:
Upon giving it more thought, I've decided to forgo the addition of sound to this project. By the time I buy the necessary components, I'm 1/2 way to a PS/3 upgrade.

So, the revised spec -
  • Will be a slave unit to a PS/2 loco.
  • Will have chuffing smoke based upon the wheel turns. A binary counter, quad AND gate, a 555 timer, and an NPN transistor will make that happen. Small, low power, and I already have most of what I need.
 

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MTH counts the timing marks on the flywheel. The correct count for that particular engine is stored in the sound file. Lots of ways to sync the smoke on the slave engine. This with a 5V power source is only about 3 bucks. Optical detector reflects off white spots on a driver. Can drive the smoke fan motor directly.
Shown with two different relays. The white ones are DPDT and costs 50 cents on ebay.

Optical_chuff_switch.JPG

Pete
 

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Discussion Starter #12
I was planning to use one of these things


and a CD4040 binary counter. Being that the gear ration is 28:1, and I want a puff of smoke at 1/4 wheel revolution, that means that the circuit will trigger at every 7 turns of the motor.

Give me a minute to draw it up...
 

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I can see how that will work, its just needs more components and you will need either a relay or transistor to drive the fan motor plus your 5V source. I don't have a MTH smoke unit in front of me so not sure if the 5V is on the smoke unit. Older Lionel smoke units have the 5V regulator to drive the fan motor.

Pete
 

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I'm partial to my solution for smoke, the Chuff-Generator and the Super-Chuffer II. Already designed, and allows you to have a programmable chuff rate locked to the motor rotation. Manages the chuffing, also gives you optional Rule-17 lighting, automatic cab light control, and even automatic ground work lights.

000c-g.png

000s-c.png

This is my prototype run, shot in 2014 when I first released the original Super-Chuffer.

 

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Discussion Starter #16
Oh this keeps getting better.

There is a nice and clean, regulated 5VDC coming off of the PS/1 smoke unit board that is used to power the fan. I can tap into this to power my logic circuit. No other power supply will be needed.

Power for the whole smoke circuit is controlled by the switch on the bottom of the loco. Switch on, smoke and supporting logic is on.

The fan motor pulls 30mA (measured). A 555 timer output is can provide 200mA. No driver transistor needed.

I estimate that the whole circuit will pull at max, 60mA. 30mA for the fan, 10mA for each of the 3 ICs on my logic board.

I'll keep you guys posted on my progress.
 

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The bad news is, that 5V supply is working about as hard as it can. That's a TO-92 regulator that has it's hands full powering the 35-40ma for the fan. I can tell you that with track power going in and 60ma load on that regulator, it'll glow a nice cherry red. :D Seriously, it'll very likely go into thermal shutdown pretty quickly.
 

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Why use only two components when you can use 57. The more the better, right? Neither the Siemens relay or optical detector will tax the LM78L05. It can drive them plus the fan and the relay could trigger a Railsounds board as well if you want chuff sounds.

The parts I used cost about a buck and half.

How much do yours cost again?

Pete
 

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Discussion Starter #19
Yeah, that little TO-92 will go the way of the 330uF/35V WinCaps.

So I will need to make a power supply - been there, done that. I have everything I need to make the necessary 5V supply, so it's just a few more minutes with the soldering pen.



Norton, What is the optical detector and relay setup you are referencing? Do you have a link?

The Railsounds board looks more or less like what I was thinking I would do with an Arduino, but at $90 for the board, it's again, almost 1/2 way to a PS/3 upgrade, which is why I dumped the sound for this particular project. If I'm going to spend that much, I'll save the $$ and just get an upgrade. The idea here is "double headed steam on the cheap".
 

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Optical detector.

https://www.digikey.com/products/en?keywords=365-1654-ND

Relay.

https://www.ebay.com/itm/Siemens-V23079-A1001-B301-DPDT-250VA-30VDC-2A-Relay-4-5V-coil-NEW-Lots-of-2/381532799167?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I was wrong, it uses three components. Add a 130 ohm resistor for the LED (IR emitter) circuit. The relay coil is wired in the collector circuit of the darlington photo transistor.


If you need a power supply. Just add a bridge.

https://www.ebay.com/itm/2XLM2596-DC-DC-Adjustable-Buck-Converter-Step-Down-Power-Supply-Module-1-23-30V/282261008912?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Thats really all you need to drive both the fan and a railsounds board. Plus you get precise 4 chuffs.

Many times this is a not a good solution especially on small engines or those too crowded to get a clear view of a back of driver but in this apllication in an engine with no other boards in the way it should be easy to implement.

Pete
 
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