Feeding the Frogs I

Overall I have been happy with how well my engine runs on LSR’s track, but there is one recurrent problem that I want to mitigate before I start placing structures and scenery permanently on the board.

My turnouts are all Electrofrog, which means they route power across the length of the turnout, without any gaps to account for polarity. Because of this, different sections of the track switch polarity based on which way the turnout is switched.

This is why, when laying track, I added plastic insulating fishplates on the inner rails where track diverges. This creates breaks in the rails to prevent crossed polarities, which would shut the layout down.

The problem with insulating that section of track is that it completely isolated the part of the turnout known as the “frog,” which is the vaguely X-shaped meeting of inner rails. As a result, the frog only receives it power from the points, which move like windshield wipers from rail to rail to route the trains.

When the points don’t press hard enough against the rails, or when the smallest amount of dust, grime, or oxidation builds up between the points and the rails, the frog doesn’t get any power, and the trains stop on the “dead” frog because they aren’t getting power in turn.

The problem, though, is that the frog needs to switch polarity depending on which way the turnout is switched. Initially, I planned to eventually purchase a “hex frog juicer” which works with DCC controls and which powers six frogs and switches the polarity automatically.

I didn’t realize until recently that the SMAIL switch motor I installed for each turnout is capable of powering the frog and switching the polarity using a built-in SPDT switch. However, this will require more wiring and probably a lot of trial and error.

As shown in the diagram, each turnout needs three feeders added and connected to terminals 2, 3, and 4, which lead to one of two SPDT switches inside the SMAIL machine, as shown here:

Terminals 5, 6, and 7 also lead to an SPDT switch, often used to trigger signals.

Over the weekend, I connected terminal 4 on each SMAIL to the frog itself. It isn’t powered yet, though, without the added feeders from terminals 2 and 3. But it’s a start! I used lengths of green 22-gauge wire and soldered them to the outside of the rail between each frog-and-point assembly.

Now to add the outer feeders to the stock rails, which will complete the SPDT circuit. There will be mistakes made, though, because which wire goes to which side of the track will be dependent on which way the turnout is facing.

I will update after I’ve installed and tested one or two.

Carriage Shed I and Some Planning

A minor victory this weekend: I finally started putting together the Peco Ratio Carriage Shed which has been in my closet since I started this layout.

Plastic kits are finicky. They don’t look great on their own; they really require some extra time spent patching seams, painting and repainting, and a fair bit of weathering to cover bodged sections.

I built my first Ratio kits a couple of years ago: the Country Station and a Station Platform. It was built for my Inglenook switching module, so the platform shape was wrong for LSR, leaving a lot of awkward space behind it. I brought it to the layout at the office where it been collecting dust since. I happened to run the office trains last week and felt sorry for the station, so I brought it home. What do you know… I’m considering repurposing it as Little Snoring’s station and bringing the Metcalfe Station to the office.

Here’s a few shots of the station:

Looks pretty good, right? That’s because I spent about eight hours just painting it. I used Krylon and Rust-Oleum rattle spray cans on all the pieces, masking off sections to paint details such as lintels and window sills. After spray painting, I used washes of diluted white acrylic paint for mortar, and washes of diluted black acrylic for shadowing and weathering doors, windows, gutters, etc. I then dry brushed the roof with gray to weather the slates. I even detailed the interior with  printed cardstock:

Still needs some furniture and a couple of figures.

Inspired by this model, I went to work on the Ratio Carriage Shed a couple of days ago. Out of the box, the model is intended to be two tracks wide, but I don’t have any place for that on my layout so I decided to cut it down to a single track width.

I used plastic cement to bind the halves together.

The kit comes with enough pieces to make two sheds, and the builder can place them side-by-side or join them to make an elongated shed. I’ve only completed one shed, and will likely connect it to the other to make a longer shed, similar to one Hemyock used to have adjacent to its engine shed.

I used Rust-Oleum Colonial Red spray paint to color the parts, then super-glued them together. There were some pretty serious gaps between the side walls and the front, so I filled them with Testor’s Contour Putty, which I then sanded down and repainted.

Finally, I used washes of diluted black acrylic paint to weather the boards.

 

I still need to add the roof, but the one in the kit is a very thin and brittle plastic. I want to make sure I know how to paint and weather it before I begin, lest I break it. Here’s a photo of the half I’ve completed beside the length of track that I straightened for the sole purpose of placing the carriage shed:

I have five or six Ratio kits still in their boxes and will probably start working on a few of them. In particular, I’ve been wanting to start on the water tower to accompany some coal staithes near the turntable.

I’m also considering the possibility that I will replace the station platform with a longer, thinner version. This would make the space behind the platform less awkward (the space behind Hemyock, the real-life inspiration for Little Snoring, was used as a car park) and would allow me to move the station building toward the left-hand side of the layout, which is ideal in terms of realism.

If I alter the platform, it would go from something like this:

config 1

To something like this:

config-2-1-e1548110581917.jpg

I will think about all this for a few weeks before deciding…

Fussy Stuff

With a pre-holiday hour to spare I straightened a couple of troublesome kinks in the track which caused the engine to shrug. I also straightened the longer curved siding where I had originally planned a goods shed. I’ve altered that plan to add a carriage shed, which requires a longer length of straight track. For that, I had to de-solder a few feeder wires. Now I need to let the glue dry on the straightened sections before I re-solder the feeders. In the next few weeks I hope to start working on the carriage shed, which I’ve been planning for a while.

Here’s a picture of our puppy, Fenton, to stare at in the meantime. He’s the reason why I’ve been so busy:

LSR Station V

I stayed up a bit too late tonight, but I made some headway on LSR’s station platform. This was a daunting step, and it took me a while to muster up the courage to begin.

I started with Metcalfe’s Red Brick Platform kit:

Then I made a template for the center platform:

As you can see, the platform takes up most of the space between the rails. This was not the case with Hemyock’s little platform, but Metcalfe’s station house is based on a building that is much larger than Hemyock’s station house.

After a bit of testing and trimming, I transferred the template to the “asphalt” surface of the platform and cut to size. Then I added spacers for the platform’s edge before constructing the walls.

Next, I will need to add some support beneath the platform (it holds the station house, but it bows a bit), glue down the ramps, and finally add the brickwork around the edge.

As you can see, the “face” of the station house is turned to the wall (compare with photos in my previous posts). I gave this a bit of thought: the building looks much more appropriate facing this direction, as the shape of the structure is tapered toward the tip of the platform.

Overall, while I like working with cardstock, the Metcalfe station looks pretty awkward no matter what I do with it. It just isn’t “right” for LSR. I may wind up donating it to the layout in my office, but I’m not sure yet.

LSR Station IV

Just a quick update: LSR’s station is nearly complete. I have only to add chimney pots and a rain gutter, and then I will start working on the platform.

Most recently I added the windowsills after painting them. That was a particularly tedious process, especially because I noticed an off-colored gap where the brick print shows between the sill and the window casing. I used acrylic paint to backfill the gap, which made a small but noticeable difference.

Before:

After:

I also started work on a small platform station, which Metcalfe included as a bonus in the station kit. I will not be using the platform station opposite the main station building, as suggested. Rather, I may include it in my next module as a halt station. Maybe I’ll start on that module in 2019!

LSR Station I

I spent a few hours today prepping Metcalfe’s N Scale Country Station. “Prepping” means opening the packet, reading the directions twice or thrice, spray painting the laser-cut pieces, and spraying Testor’s Dullcote over every sheet and piece (to protect from moisture, but also to give everything a dulled-down appearance).

After prepping, I started putting together the first building: the Station Master’s House.

This consisted of cutting the pieces away from the sheets, then folding the scored lines to create corners. While folded, the corners expose the bright white card under the printed layer. To blend the corners, I painted them with watercolors. I also painted the white edges around doorways and windows.

Then I layered the window and door frames behind the walls, and the windows and doors behind the frames. There were also other structural components that will be hidden after the model is complete.

For most paper and card projects I use Aileen’s Tacky Glue, and this is no exception. I used to do quite a bit of bookbinding and I found that Aileen’s dries much faster than Elmer’s, although it is almost identical in every other way: it is water-based, can be applied with a brush, and it dries clear. I used Roket Card Glue a couple of years ago, which is what Metcalfe recommends, but the shipping cost was steep (it is only sold in the U.K.) and in my opinion it didn’t perform any better than Aileen’s.

So far, so good. Metcalfe models are fairly user-friendly in that they are well designed and don’t require much painting or detailing after they are built.

I will work on more of the station over the course of the next week.

Turntable VIII: Microstepped

Trying to get the turntable to rotate more slowly while remaining smooth turned out to be a challenge. When slowed down, it began ticking like a clock with enough torque that it would likely have flicked an engine off the deck. My brother-in-law and I spent a couple of hours last night trying to figure out a solution, to no avail. After that I stayed up way too late digging through Arduino forums, trying to figure out how to add a microstepping sequence to break up the “tick-tock” movement into much smaller waves. I went to bed thinking all that research was for nothing.

When I woke up this morning, though, I had the sudden idea that maybe the Adafruit motor shield has a library with a microstepping sequence already loaded. This would save us from having to make calculations and then pull in (or invent) strings of compatible code from other sources. So, after a quick reread on Adafruit’s informational website I verified that, indeed, the Adafruit is already programmed to run a microstep sequence.

Lo and behold, all I did was replace instances of “Single” with “Microstep,” uploaded the code to the Arduino, and suddenly the turntable is slow moving and smooth.

Here’s a video of the turntable moving slowly and smoothly.

I think we can adjust the code further to give the turntable a more realistic appearance by accelerating and decelerating the deck every time it moves. For now, though, I am happy with how it functions, so am posting the code here in case anyone else can make use of it:

#include <NmraDcc.h>
#include <Wire.h>
#include <Adafruit_MotorShield.h>

#define DCC_ADDRESS 6 //Change accessory address here.
NmraDcc Dcc ; //Declare DCC Shield.
Adafruit_MotorShield AFMS = Adafruit_MotorShield(); //Declare Motor Shield.
bool firstloop = true;
//Comment: getStepper(steps, stepper#)
//Stepper# is which port the motor is connected to. If using M1 and M2, indicate port 1. If using M3 and M4 indicate port 2.
//NEMA 14 Stepper Motor has a 0.9 degree/step. 360/0.9 = 400.
Adafruit_StepperMotor *myMotor = AFMS.getStepper(400, 2);

//This function is called whenever a normal DCC Turnout Packet is received.
void notifyDccAccTurnoutOutput( uint16_t Addr, uint8_t Direction, uint8_t OutputPower )
{
Serial.print(“DCC Turnout Packet Received\n”);
if ((Addr == DCC_ADDRESS) && OutputPower){
Serial.print(“Move 180 degrees\n”);
myMotor->step(200, Direction, MICROSTEP); //Move 180 degrees in the specified direction.
} else if ( (Addr == (DCC_ADDRESS + 1)) && OutputPower){
Serial.print(“Nudge 1 step\n”);
myMotor->step(1, Direction, MICROSTEP); //Move 1 step in the specified direction.
}
delay(200); //Wait 200 ms for debounce.
}

//setup(): This is executed first and only one time.
void setup()
{

Serial.begin(115200);
while(!Serial); //Wait for the USB device to enumerate.
Serial.print(“Start Setup\n”);
AFMS.begin(); //Create with the default frequency 1.6KHz.
myMotor->setSpeed(0.025); //Set speed for 1/2 rotation per minute.
Dcc.pin(0, 2, 1); //Setup external interrupt, the pin it’s associated with that we’re using, and enable the pull-up.
Dcc.init( MAN_ID_DIY, 10, CV29_ACCESSORY_DECODER, 0 );//Call the main DCC init function to enable the DCC receiver.

Serial.print(“Setup Over\n”);
}

//loop(): If the DCC function detects a signal, it will call notifyDccAccTurnoutOutput on its own.
void loop()
{
if (firstloop) { Serial.print(“First Loop\n”); firstloop = false;}
Dcc.process(); //Calling this method makes the DCC shield check for new communications. It must be frequent or a message may be missed.
//myMotor->step(200, FORWARD, DOUBLE); //Move 180 degrees in the specified direction.
//delay(5000);
}

Turntable VII: Motorized!

The stack is in place and wired up.

Initially I had some issues loading the code into the Arduino, and finally worked it out with my brother-in-law’s guidance. I’d been loading it correctly, but a command was missing that caused the motor to remain unresponsive. Once that was sussed out the turntable started working without much of a problem, at least while it was powered via USB.

An issue arose when I powered the Arduino with 12V DC. When the motor was running on that voltage, it got sizzling hot and moved erratically when activated. However, when I switched back to the USB cable (which is regulated at 5V) it worked perfectly fine.

We are working on that, and then we will be keying in a slower speed. Ideally the deck will rotate at 1 rpm, but it is currently closer to 4-5 rpms. Overall, though, I am very excited and relieved that it is able to run!

Here’s a video of the turntable in action. You can see both the 180-degree rotation as well as the 0.9-degree nudge (just in case the deck goes out of alignment).

Edit: I think I’ve pinpointed the issue with the DC supply. While the motor indicates that it is a 12V motor, to be safe we should have calculated Ohms Law, which tells us that a  source should never exceed I=V/R (or “Current” equals “Voltage” divided by “Resistance”).  Any more than that and the motor will draw too much when idle (it draws the most voltage while holding). My brother-in-law and I both assumed that the motor shield would regulate the voltage.

For my motor (as per the specs listed on the packaging):

V=0.5A
R=17 ohms
I=0.5×17
I=8.5 volts

Thus, according to Ohm’s Law we don’t want the voltage to exceed 8.5 volts. I guess that is what the motor specs mean:

“Each phase draws 500 mA at 8.5 V, allowing for a holding torque of 7Ncm (10oz.in) … Rated Current/phase: 0.5A … Phase Resistance: 17 ohms.”

To be honest, that’s mostly Greek to me, but the numbers align with my math.

I’m not too concerned with torque (because there isn’t much weight or resistance on the turntable) so 5 volts should be plenty. The motor has been working just fine on the 5V USB, but I would prefer a straight DC supply because I may decide to add a USB extension between the USB port and the fascia.