Servos Wired

Over the last few days, I have worked my way along to completing the servo installations for Comstock Road. There was a bunch of other wiring tasks required that got done while I procrastinated on the servos themselves. When I actually got around to them, things went reasonably well although I did have to get out the multimeter at one point to debug what turned out to be an insufficiently inserted Anderson connector lug.

More or less in order, I did the following:

  • installed the board that holds the Octopus board and relays
  • connected the control panel to above. (OK, order did matter here)
  • ran wires from the relays to frog feeders
  • ran a servo cable from the controller to the runaround turnout which is the only servo not on the center baseboard section
  • applied Anderson Powerpole connectors to the runaround servo cable to span the gap between baseboards and jumper connectors to both ends
  • ran a cable and jumpered the other servo run which is not right next to the control board
  • bent up the link wires and installed them through 1/16th” brass tubes
  • actually installed the servos
  • tested everything, (multimeter comes in here)

The next step will be to make up the throw bars and link them up so I can align the servos and run some trains.

Here is the control board wired up. I used some small wire wraps to tidy things up a bit. Without the wraps, the y-cables connecting control panel, relay and controller made a bit of a rats nest.wiredcontrolboard.jpg

At the other end of the center section, I created a “cable” by wrapping all the wires going into the Anderson plugs with electrical tape. This makes it less likely that the smaller gauge wires will get damaged when the connection is made and unmade.wiringharness.jpg

Note that only the white and grey DCC bus wires look like they need these robust connectors. In fact, I had to solder the servo and frog wire to the lugs before crimping them since the crimp isn’t tight enough to grab the small gauge wires.

Octopus On A Plank

I have some task to perform this weekend that will take me out of town on Sunday so hobby time is limited but I did get something done. Permanently installing the Tam Valley Octopus III and attendant remote relays will require me to mount them in close proximity to the control panel. There isn’t any large wood surface in that location or in any other for that matter, this being the downside of non-solid wood topped baseboards. There being no wood surface available, I determined to provide my own.

I measured the boards and pondered their optimal orientation in relation to each other and to the various connections that would need to be made. I then cut a 3″x 8″ hardboard rectangle, drew some guide lines on it and attached the boards with 3/8″ #4 wood screws.

It isn’t fancy but all the boards are securely mounted so that plugging and unplugging won’t cause something to come loose. I will screw the board to the underside of two subroadbed sections so that the board is accessible between the baseboard bracing.


The blue terminal blocks all handle power of some sort: track for the relays(red boards) and servos for the Octopus board. The black connectors on the relays and the C 0-7 header on the Octopus connect to the controllers on the panel via Y-cables. The less ideal bit is that the cables to the servos connect on the header on the left side of the Ocotpus. This was the least bad choice since the connector for the Remote Alignment board (right side) needed to be easy to get at since it’s cable will get repeatedly plugged and unplugged at least until I get things all set up.

As a note, the relays are what seemed like the best solution for switching frog polarity when I bought the Ocotopus-III several years ago. If I was doing this from scratch, I would use a Frog Juicer instead especially now that I have used one and seen how simple it is to wire up.

Diamond Frog Juice

I have been test running back and forth looking for mechanical flaws in Comstock Road’s trackwork. Whilst so engaged, I discovered that the two isolated and as yet unpowered frogs on the diamond are both as long as the SW-8’s trucks and spaced almost exactly the same distance apart. This was obvious as the locomotive persistently lost power crossing the diamond at slow speeds. (Faster speeds allowed the capacitor to get it across the gap in time).

Fortunately, I recently purchased a Tam Valley Dual Frog Juicer for just this eventuality and got it installed tonight. Several post-installation test runs have failed to produce a stall so it looks like the device is earning its’ keep.diamondfrogjuice

This is probably the easiest installation I will get. Four screws, four wires and done. I think I spent more time reading the instructions than actually hooking it up.

As an encore, I broke out the servo connector wire kit I have assembled from various vendors. The combination of purpose specific three strand wire, connector kit and crimpers will allow me to connect servos to Octopus-III board and control panel. And the vast quantity of parts will allow me to mess up the occasional crimp. Score is 6-1 so far…jrkit

Electric Sunday

Today’s model railroading efforts were devoted to wiring. I connected up the feeders for the balance of the layout. I then tested the main and one path through the diamond and am happy to report that all went well except for the occasional loss of power due to dirty rails. Rail cleaning ensued. Since rail cleaning improves electrical contact I am calling that electric related.

I then drilled the holes for the three remaining turnout servo linkages. At that point, I realized that I was going to want a control panel since the minute you have two unlabeled push buttons dangling off an unattached board you have a user interface problem.

I then assembled four more Tam Valley fascia controller kits (one more than required so I have a loose one for servo installation if I need it). tvdcontrollers

I am unsure of what form the final control panel will take so I am not investing a lot in a panel right now. I therefore bodged up a quickie panel out of hardboard using basic drafting tools and the paper template supplied with the controllers. Ten minutes with a center punch and the drill press gave me all the holes required. A bit of sophistamicated graphic artistry with a straight edge and the big marker and the temporary stand-in was done.bodgepanel

This will work for me as a start and allow me to experiment with panel locations. This is my current best choice but I am not thrilled with the proximity to the creek bed to the right.

Power Strip

I made a minor investment in Comstock Road’s infrastructure by installing a dedicated power strip one the sub-baseboard frame. This will allow me to plug in the “wall wart” power supplies for the servo controller, the traverser mechanism, and whatever else I end up with (animation, structure lighting,…) and run one cord to the dedicated switch outlet. Prone as I am to getting focused on a task and obliviously kicking and tripping over things, I felt it prudent to organize things out of the way before I accidentally ripped some cord out of something.

This also represents the first time I have actually been under the layout since I set it up since I can usually just flip up a baseboard section to get at the underside. A sweep up of floor usually covered by stuff was indicated. No lost treasure was found.powerstrip

The scrounged power supply currently powering the servo controller is obstructing an outlet despite the spacing. I may have to see a squarer replacement if I need that outlet in the future.

Turnout Control Conclusion

If you have been following along, you know that I have been attempting to devise a way to throw Comstock Road’s turnout points using a servo and a rotary motion mimicking a manual switch stand. The initial attempt using the mounting scheme appropriate to the typical back and forth scheme was not a success. After much scheming, I became resigned to having to mount the servo face towards the baseboard bottom and with shaft in line with the vertical throw shaft.

Happily, I came across a similar scheme used and well documented by the Delmarva Model Railroad Club that I could adapt to meet my goal. Rather than use a couple of blocks of wood, I used a couple of pieces of aquarium bubbler hose and 1 1/2″ #6 wood screws.

Before I tipped the center section up to get at the servo location, I taped down the points, throw bar and all. This kept things centered as well as prevented the pins holding the throw bar from falling out. Family lore includes the time we tilted a sofa bed while lugging it up the stairs and it went sproing. All subsequent movements start with tying those suckers shut! Note that digital photography has not stopped me from exercising my talent for getting a finger into the shot…boughtthatfarm

Things secured and disconnected, I tipped up the section, clamped it in place and re-bent the vertical wire to the new spec. The horizontal leg has to match the distance between the servo shaft center and the last hole on the servo horn.turnoutwiremk2

I plotted out the mounting holes to put the servo horn perpendicular to axis of the servo mount at center. This turned out to work but only just. The servo shaft is not centered in the housing so the near mounting screw interferes much sooner than the far one. The interference issue is only relevant when you invert the servo like this. Future installation will offset the center point to split the difference in the available travel.servobracketmk2

I tried to capture the situation when the turnout is thrown to that side. The servo horn is right up against the tubing but the turnout is thrown so we will call that a win.servohardover

Finally, I am awaiting the arrival of appropriate bits and bobs to wire the servos, controllers and driver board permanently. I can still operate one turnout at a time at close range via temporary measures. Also note that I forgot to install the frog polarity relay while I was “under’ the layout. One more for the checklist.verytemporary

I did a run of the test train to prove things worked so I can now claim to have an operating layout. I can now perform an Inglenook scheme via this turnout, the back track and manually pushing the traverser. Or at least I could if I had enough cars converted to P:48. I will need to do an inventory and get that under way.

Getting one turnout is not a huge deal but getting a working method sorted out to my satisfaction is a mental obstacle overcome. Onward!

A Bit More Turnout Control Progress


Pictured above are in order, an Octopus III servo controller, remote relay, fascia controller and micro-servo, all from Tam Valley Depot. I bought a bunch of each for the previous layout and never did get any of it deployed so I am both pleased to be finally using it all and having to learn how to do that.

Tonight I soldered up a fascia controller kit (two LED’s, a button and a connector) and messed around with the remote alignment board to get the hang of it. I think I can do it all now including, ahem, factory reset the Octopus in case I mess it up. Hypothetically speaking. 🙂

Next concern is that the required throw for the points is about 100 degrees of rotation. To get that out of the servo will require it to be quite close to the point of rotation which creates other alignment issues. I am having a bit of a ponder about what to do about that. I will also tip the board up for the next bit of fiddling since I can’t get under the bracket location with a screwdriver due to the sub-baseboard. Hopefully the assorted point bits won’t fall off since I haven’t permanently attached any of it.

Turnout Control Progress

I have mentioned previously that getting hand laid points connected up and suitably under control has been a stumbling block in past efforts. The achievable scope of Comstock Road (4 or 5 turnouts total) makes the mental size of the task easier to contemplate. I have begun the new year as I mean to go on, by tackling the mentally hard things and have made further progress.

First up is the connecting rod from switch stand location to throw bar. Increasingly prototypical possibilities have occupied my imagination but when I found myself contemplating scratchbuilding scale clevis’, I realized that I was making things harder than they should be, certainly for a first attempt. I resolved to make something out of the piano wire on hand.

I needed an eye or loop in the wire to connect to the vertical shaft comping up from beneath the layout. (I am going for a rotational motion like a switch stand rather than the model railroady back and forth in a big hole. I fashioned a simple jig consisting of a piece of scrap plywood with a nail driven in and cut off, and adjacent to a piano wire sized hole. A right angle bend near the end of the wire goes into the hole and the wire is wrapped around the nail to form the eye. I got the idea for this jig from the Animated Scale Models Handbook.

Here is the jig.bentwirejig

And here is the result trimmed up.eyeinwire

I have got the vertical brass tube and wire combo installed and connected to the throwbar. (We pause while I dash downstairs to take a photo of the installation which I apparently forgot to do. Lack of photos is usually a good sign since it indicates that I have got a head of steam up.) Here is a shot of the connecting rod installation. Bending the crank in the end of the vertical wire was a challenge and I will consider better alternatives such as soldering on a separate piece of brass bar. It does work and will be concealed by the switch stand. The other reason for a separate bar would be to allow the vertical wire to continue up through the stand so the target can rotate.connectingrod.jpg

Finally, we get to installing the servo, Tam Valley Octopus servo driver and associated electrical bits. I have got as far as fashioning a bracket for the servo using a section of 1/2″ aluminum channel from the big box store. I picked this idea up somewhere in the model railway reaches of the internet and it works a treat. The servo is just a friction fit in the channel after a slight pinch with a pair of pliers.bracketmk1

Weekend Reading: Animated Scale Models Handbook

animatedscalemodels.jpgWhile I was in Kingston, ON on Saturday, I was able to take a bit of time to visit the Kingston Railfair train show. As is my habit, I browsed through the used books because one can never have too many books! I was lucky enough to come across Animated Scale Models Handbook by Adolph F. Frank. It was inexpensively priced so I took it into custody out of curiosity.

I am pleased to say that I am not disappointed in my latest acquisition. I have not finished reading it yet I soon will. Published in 1981, Animated Scale Models describes methods, materials and mechanism for animation predating the advent of inexpensive microcontrollers, stepper motors and servos. While some of what is described has been superceded, much of the wisdom of creating mechanisms from simple materials still looks useful.

Materials and tools described are only the ordinary sort that can be easily obtained. While the tool list certainly does not include a lather, I am also certainly going to find things to do with mine in this book. And save money either way. One can buy pulleys from a hobby robotics supplier, for instance, but the cost can add up in a hurry. Using the techniques in this book, one can readily build inexpensive alternatives that are exactly what is needed.

The book itself is soft bound and printed on non-glossy paper. It is well illustrated with plenty of clear drawings but despite the blurb on the back cover, no photographs other than the one on the cover. No pretty pictures here, just the stuff you actually need. Chapters include basic components, speed reduction mechanisms, mechanical movements,  and various example projects including a ferris wheel, a factory with a bicycle assembly line and more prosaic things like a small house with a man swinging a hammer to repair the roof and grandma rocking her rocking chair on the porch.

I think I can safely assert that any model railroader could find something useful in the Animated Scale Models Handbook. I look forward to employing some of these techniques to liven up Comstock Road. While apparently no longer in print, the online book retailers seem to have multiple used copies available at very attractive prices if you are interested.

Jeweler Saw Practice

Having just finished the electronic part of installing a DCC decoder in Comstock Road’s lone Atlas O SW-8, I set out to finish the job by making sure everything was correctly insulated, taped down and able to fit inside the diecast metal shell. Perceptive readers might wonder why I mention the shell material. That is part of the fun!

Getting the wires all tucked in was not too much of a challenge but I then discovered that my estimation of clearance between speaker top and shell was, er, optimistic. The issue was the speaker mounting lugs cast into the inside of the shell. They are almost a fit for the chosen TCS speaker but only almost. I have also elected to not attach the speaker to the shell to give more clearance for a future detailed grill.

Here is what the inside looked like when I started.sw8mountlugs

Since the lugs had to go anyway, I resolved to “daylight” the opening back to something akin to the prototype rectangle. This would give plenty of room for the speaker to shoot upwards.

I got out my trusty jeweler’s saw and my excessive supply of #0 blades. Back in the day, I bought a gross of this blade size in a fit of enthusiasm and only afterwards discovered that #0 is too coarse for .015″ material. I have despaired of every finding a use for all those blades but no longer!

Even the relatively heavy #0 blades are fragile and do not tolerate careless use. You can turn corners in a cut but you have to carefully saw in place while rotating cautiously. If you push to hard you can jam the blade and snap it. Letting the work twist on the blade while repositioning can break a blade… You get the idea. Fortunately, I have about 12 dozen blades for just such an emergency. Or I did. I am now better at sawing and have less blades.expendovblades

Eventually, I got the opening cut out to my satisfaction. Here is the view from above with the shell on. (Apologies for the bad focus.)speakerhole

And here is the top view with the stock screens and grills back in place. All being black, the speaker is not visible unless you get up close and look straight.sw8postsurgery