Dingleberry, a N Gauge test track

[aleopardstail]

both long sidings, and the adjacent track section between the two currently unused turnouts now have the IR proximity sensors installed, they are now all also fully glued down. need to print off, transfer, etch, drill, cut and assemble the next batch of proximity sensors - that will give me the four on what will be the outer loop of track (each of which will eventually have a signal associated with it) and the two for the sidings (so inbound trains know when to stop before going splut).

 

can then start to consider the inner loop, which needs another five such sensors (four blocks but one of them is bi-directional so a sensor towards each end).

 

currently these are just being tested but not actually hooked up - same as the current transducers for the inner blocks will be installed but not fully wired up.

 

need to revise the point motor servos to include the position sensor switches (and to be centred a bit better), means cutting some more channelling and configuring to put the mounting screws into different positions which isn't hard to do.

 

this is the "fiddling" stage but actually quite enjoyable, now the basic techniques are down things can be installed even if the actual operation is all a bit basic

[aleopardstail]

Experimentificating!

 

 

this blurred mess demonstrates two things, firstly my iPhone is really rubbish at close up photo work, and secondly that it is possible for me to create a small circuit board and hand solder 0603 surface mount LEDs

 

 

more amazing was that is actually worked, this is a prototype for a 4 aspect colour light signal head. it has shown me a few things, mostly I need a better way of cutting the board for things this size, also that I need to find a slightly different way to actually wire it, may enlarge the upper side of the anode solder pad (top in the pics) so the wire can come out the side to wrap around to the rear of the board where they can be twisted (the wire is enamelled)and then fed down the inside of a narrow brass tube.

 

the PCB is 0.4mm thick, in theory double sided but only using one side here (there is no way I could drill accurately enough to go through the centre of a pad)

 

does however show that in theory at least I can make working colour light signals

[aleopardstail]

bit more rolling stock arrived this morning, quartet of GF Mk3 coaches, here nicely demonstrating that the two longer sidings are not long enough for such.

 

 

to be honest I really only wanted some Mk3 <i>now</i> for gauge clearance testing, at best the layout supports a 2+2 HST which to be fair looks to my eyes a bit silly anyway.

 

still, they are quite nice

 

have also etched boards for more IR sensors, will drill these later, track loop needs three more currently which once tested can see the outer loop fully secured down.

 

also have some conductive paint so plan to try a 10k resistor retro-fit to a coach and see how the detection system handles it (and to try a comparator based current sensor in place of the current ADC versions)

[aleopardstail]

*coughs awkwardly*

its been a while, however this project is far from dead, more track has gone down, though still not all of it - the loco depot remains a paper project for now.

naturally within a few minutes of the board being back on the desk for testing a squatter arrived..

 

so far the track that is down is actually wired up, the underside being a bit of a mess but for now it will do

 

 

the light blue and orange blobs are current transformers, these are to be removed (some already have been) as I'm moving over the MERG occupancy detectors to save whats left of my sanity - yes I can make perfectly workable ones myself, indeed I have, but the MERG kits look a lot less trouble and for the price.. so yes..

 

the next job now that the track is powered and has been tested and it all works (after adding another feed and repairing too loose wires) is to fit the next eight point servos which I hope to start work on later tonight with the brackets being finished and to start installing tomorrow to test over the long weekend.

 

will then get the C/MRI interface stuff re-attached and can actually play trains again.

[aleopardstail]

Blindsided today, literally jaw dropping.

 

Joined MERG on Tuesday and ordered a couple of block detector kits to experiment with, expected them sometime next week, maybe week after..

 

They arrived today.. Amazing service

 

assembled them, though without the header pins as I want all screw terminals and they have yet to arrive. The LED replaced with a pair of two pin headers so the LEDs can be mounted where I can see them to try it all out.

 

worked first time, picked up some old coaches with 10k resistors on one axle perfectly as well (once I cleaned the coach wheels a bit)

 

screw terminals due next week and then will hard install the first two boards, only wired up the two longer sidings initially to test things, next up will be adding the board outputs to a C/MRI enabled Arduino to provide some feedback.

 

very happy bunny

[aleopardstail]

I got slightly bored earlier, so decided to hook up the point servos, so far of the nine connected, eight work, the other fails to respond so a bit of debugging needed - its set in the right direction so not too bad.. Just means nothing can drive into the TMD, which since that doesn't yet actually exist is perhaps a good thing.

 

I'm using normal SG90 servos and a PCA9685 control board, a clone of the Adafruit board, to drive them. easy to use and works fine. Thats installed on the underside of the layout with various extension cables to reach the servos, I'm hoping for a layout this small extensions will work fine, anything larger and would likely have a few controllers.

 

This is in turn controlled by a microcontroller, it would have been easy to use an Arduino, however because I was experimenting I've used a Raspberry Pi Pico which makes adding a small screen and keypad quite easy without running out of memory, the controller itself is still on breadboard but it works

 

the blue and yellow wires go to a 16 key touch pad controller, connected via I2C. the wires going off the bottom of the image go under the board to the controller board itself.

 

this is running some custom code that drives the screen, it needs updating as there are two modes, here its in "manual" mode used to adjust the individual settings - the display shows its configuring servo #0, which will go from -25 degrees to +35 degrees from the mid point, and will on power up go to the mid point. it is set to take 1 second to go from one end to the other providing a nice visually appealing and not too noisy operation.

 

ok actually changing the point position via this is cumbersome to say the least but it works, the breadboard also has an RS485 module and the Pi Pico is running a C/MRI driver so once that adaptor is added and wired up this will talk to JMRI to do the actual leg work - just needs a software update so it takes the commands to drive the 16 servos but also reports back all 16 positions using 32 channels (each servo getting 2 bits to show the two settings and also a third state for "in motion")

 

all in happy, and the test train trundled round nicely

 

 

here you can also see the touch keypad, its labelling isn't exactly ideal, it may get a paper overlay added

 

[aleopardstail]

Progress!

Spent a bit of time with the servo point controller, was having an issue whereby it worked, but there was no feedback to JMRI as the points moved. Bit of a rewrite and the controller now pretends to be a 32 bit in & 32 bit out SUSIC module, 16 outputs driving the 16 servo slots (8 installed), and 32 inputs provide each way sensors for each of them in pairs - so I have "clear", "Throw" or "Inconsistent" while the blades move.

 

took a bit of debugging of the hardware code to stop the thing stalling and jittering, mostly by adding some code so it only attempts to actually change turnouts that need it and doesn't try to set all of them each time one changes. that done and can now drive them all from JMRI

 

which is nice

 

next up is some hardware track fault diagnostics, one of the crossovers and the turnouts for the two long sidings are causing trouble, can run through the crossover in straight, but throw it and trains stall. there is power when checked with a meter so its not a blade contact but a train there stalls, not getting a short circuit cut out but something is causing a power drop. same happening with the siding turnouts, again fine clear but set for the diverging route and train stalls. All the others, installed identically are fine so taking a bit of head scratching.

 

next job is to get the circuit moved from breadboard to stripboard and mounted under the baseboard out of the way, also have found enough servos to power up the remaining installed points which should allow trains to traverse all the laid track and then short of the yet to materialise TMD the layout to start being operated at a basic way.

 

after that its a second Pi Pico to listen to some MERG occupancy sensors and to start the process of sensoring up the track.

[aleopardstail]

Final few bits of track on order to allow the TMD to be installed, will take a while to throw in all the point servos etc but the track being down means I can start painting it, which will be nice.

 

counted up the power feeds, for a small layout there are a lot - 32 currently, will be 40 eventually. Why so many? why so utterly over complicated? well part of the purpose is to experiment with automation so for each "block" we have at least two feeds, a main bit and an "end bit", the odd bi-directional section has two "end bits" and a middle, sidings typically have two, a main bit and an end bit etc.

 

the TMD will be wired similar though no intention of automating that, but more there because at that point why not?

 

waiting delivery of some header pins and the point controller will be on stripboard, recoded to change the pins used on the Pi Pico for a more sensible layout, but that now works so just needs building and fixing to the underside.

 

3d printer on order also, not just for the layout, but that means I can start on platforms, retaining walls and similar as well so hopefully some more interesting visual progress over the next few months

[aleopardstail]

final sections of track have been added.. to be honest if I had planned this better track laying would and probably should have been a single weekend's work..

 

and it was, just a very long weekend.

 

 

TMS track now added, inspection pits installed, all the dropper wires soldered, buffer stops glued in (and the beams painted so I can find them on the brown carpet), holes for point servos drilled, the little plastic mask to avoid the entire 8mm holes being visible added etc.

 

bit of cleaning to do, waiting just on some more 0.8mm piano wire and the rest of the servos go in (7 to add) and then thats the actual mechanics done.

 

step after is very likely starting the "concrete pad" for the shed and likely a few bunded bits for a fuel point and off load point and a bit of roadway where is crosses rails in front of the shed - then onwards to painting..

[aleopardstail]

new track sections wired in and tested, one exception the small siding towards the front of the new area is not connected yet - this will eventually be the DCC programming track and needs a pair of DPDP relays wiring up - the first will swap it from "track source" to "DCC programming source", the other will be swapping the "track source" from DCC to a DC feed (not yet connected itself) - this so I can use the whole layout to run a single DC locomotive when testing/running in prior to DCC conversion.

 

nice when one of the ancient Lima Cl86 ran first time.

 

also the TMD is wired slightly differently to the rest, its all one "block" as I'm not using automation or block detection on any of it, equally while the pointwork is all set track insufrog I have wired each siding to always be live and made sure in effect to feed all the points backwards, thus at no point in that area does electrical continuity depend on the switch blades and stock rails making contact.. something I seriously wish I had thought about for the rest of the layout as this seriously improves running, not easy to retrofit elsewhere either due to the way most of the points have insulated joiners directly on the common crossing outlet rails for section gaps - we live and learn.

[aleopardstail]

Slight touch more progress, now the TMD is physically present and the programming track is there the switch gear to toggle it mentioned previously is needed.

 

well today I wasn't doing much else so hence:

a pair of DPDT relay boards built (and tested, they have a tick and everything). pretty basic driver circuit, the LED isn't overly needed as these will lurk under a board however nice to have and I have a heck of a lot of LEDs so why not?

 

Next up, get these installed so the default no power to relay mode is "DCC track" & "programming track in running mode". this also then allows the DC running, meaning that controller needs setting up (L289N motor controller and an Arduino)..

[aleopardstail]

got bored 

 

installed the relays, wired up the L298N module and added some flying leads..

 

 

rubbish flash pic but can now drive DC locomotives, ok only one at a time as the whole layout is live but means can test/run in which was the goal. means the #25 (pictured) and #47 could be given a run, old Poole era models but I like them, oh the benefits of all wheel pickup over the even older Lima #86s I have which currently are the only ones DCC fitted.

[aleopardstail]

DC controller modified slightly, this will lurk under the baseboard eventually (though the relays are set so unpowered the layout will run in DCC mode so can run without it). In place of the 10k potentiometer & screwdriver control method the arduino driving it now responds via its serial port to some very basic commands. basically send "f 128" and the thing goes forwards at half speed and similar..

 

this will allow it to be driven by another arduino eventually via a small 5 pin connector that can sit in a handset, but for now it means can drive via the USB lead... point was to make it easier to oil the two old GF diesels and let them run for a while. discovered the Cl25 isn't happy round curves in one direction which suggests a dodgy connector, fine the other way though so a job for the future.

 

forgot just how noisy old models can be.. the XPS under the track and the glue is limiting the track noise pretty well, just the wheels and the gear sounds from the ancient motors & gear trains.. I think that once the tracks are all done, points etc working correctly I may have to consider buying a newer locomotive of some sort just to see what the newer generation are like.

 

by eck though the smell of running these brings back memories of when I was somewhat smaller and quite a bit lighter.

 

youngest (21, on leave from the army, where the heck did those years go?) said "so presumably this is just mucking about and when do you start the bigger one?"

[aleopardstail]

Analogue controller now installed

 

complete overkill with a Nano for just driving the L298N board but the clones are cheap so not too bothered, not made the handset module as yet but that can wait.

 

Then cut the remaining 7 servo mounts, the usual 15mm Aluminium C channel, same stuff I've used before but a new length.. someone has decided a slight cost saving can be made by fractionally narrowing the walls of the channels, as a result the servos are no longer a friction fit - this is exceedingly irritating to say the least.

 

experimenting with a 3d print design for a basic servo mount I hope will resolve this, if it works will print a few more.. Grrr

 

meanwhile the underside of Dingleberry is gaining more wires by the day

 

you will be please to know that no wild "cable managements" were harmed during the manufacturing of this mess, the most shocking thing is that it actually works, quite a bit more to go in yet

[aleopardstail]

benefit of owning a 3d printer, Ender 3 V2...

 

 

simple custom servo mount, servo clips in and out if needed, held securely, frame then screwed in place, actuator wire through a hole that in theory is there but in practice needs drilling (as I set the thing to low quality/fast print)

 

crude but it works

 

 

installed, takes about an hour to print each one, likely one more tonight (need some extension leads for the servos to arrive anyway to hook them all up) but installs easily enough

[aleopardstail]

incidentally, in the unlikely event anyone wants this the .stl file is on thingiverse, likely do one that can take microswitches at some point but for now don't actually need it

[aleopardstail]

last five servo mounts printed, hope to install tomorrow and promised the extensions to wire them due Wednesday...

 

job after that is to shift the controller from breadboard to stripboard and get it physically installed

 

and the job after that is to investigate how hard it will be to power the crossing rails with dedicated feeds from the stock rails of the remaining points (so I'm never depending on switch rail - stock rail contact for anything electrical)

[aleopardstail]

all motors now connected, one point (#13, go figure) is not responding, past performance indicates its probably wired in backwards, will investigate further. otherwise all working and now configured, bit of fine turning when the lot is tested and a few actuator arms to adjust in length slightly.

 

frustratingly the hole in the tie bar is close enough to the turnout that its quite possible for the actuator to catch passing side frames if not set just right - a bit easier to adjust with the newer servo mounts as not too hard to stick a 0.5mm or 1mm "shim" in the right place to slightly adjust it.

 

overall happy so far, will get point #13 working and then spend a few days testing, which is serious stuff and in no way shape or form is like playing with toys, it just happens that to the untrained observer it looks exactly the same

[5BarVT]

I’m enjoying your journey.  Servos, 3D printing and Arduinos are not in my scope yet, but I’m still enjoying your stories.

Paul.

[aleopardstail]

done some investigation. the "non functioning" servo is nicely locked solid as if its on power, power off and can be moved manually and returns to the locked position when powered on - swapping wires round between servos indicates the servo is working fine, thus its a control issue - can't blame anyone else as I wrote the code on the little Pi Pico that is driving that.

 

digging into that is a tad more work as it means rearranging the desk to get at my Pi 400 development machine and then hooking it all up, if I had to guess I have at some point used #13 for device testing and its got a hard coded test output I've used to auto centre servos at some point (the one on the board returns to the centred position).

 

will likely have a look later as need to rearrange the desk for tomorrow anyway (work stuffs).

 

the joys of debugging hardware & software systems. Still on the plus side I have a Pi Pico talking to the PC over C/MRI which I'm quite happy with, really do need to get that actually installed properly out of the way

[aleopardstail]

this is... odd... I've gone into the servo driver code, and basically nothing in there that differentiates between the servos, all 16 use the same code, the only difference is which of the control registers get written to..

 

yet still one behaves differently, will have to see if I have a spare driver board somewhere and do a bit of bench testing, I do hope thats not the problem as replacing the driver board will be an embuggerance as its got a big sticky pad holding it in place currently

[aleopardstail]

FIXED!

 

problem was classic PEBKAC.

 

turns out the code I wrote was cleverer than me, it knew -5 was smaller than +15, and I somehow missed that and was telling it to start at +15 and to increase until it reached -5... and vice versa, the code seeing thats gibberish sensibly decided to sit there and go "nope".

 

in effect an ID10T user configuration mistake.

 

now have all 16 turnouts working, and driven via JMRI, though not yet with an actual panel but can control directly from the control table, and each is connected to a pair of virtual sensors managed by the driver software so it can report when the turnouts are usable or when they are moving, and all that works nicely.

 

onwards with testing!

[aleopardstail]

a pair of slightly elderly class 86 by Lima, each with three similar vintage Mk1 coaches, also by Lima, having a bit of a run out

 

 

initial track testing showed that by eck there is some track cleaning needed, not helped by the twin axle pickups of the locomotives. Also one or two turnouts do indeed need a shim adding as the actuator arm is slightly too long and catches on the subframe - e.g. the depot entry point is fine in straight running but blocks on the diverging route into the tmd itself. that apart it does appear to actually work which is good and once the locos have run for a bit they are a lot better at stopping & starting without the divine finger of "nudge" helping. and also very nice to sit back and control the lot with the mouse

 

given the two DC only (currently) locomotives do run a bit better I need to get them chipped at some point, could also do with a slightly more modern locomotive I suspect, but need one that can cope with 1st radius curves and settrack points

[aleopardstail]

more testing completed, and yet more track cleaning and loco wheel cleaning, waiting for the Zimo 617F decoders to be back in stock at sensible prices and will get the Cl25 & Cl47 converted.

 

Also have some more of the MERG block detection boards on order, not enough for the full layout (some 33 blocks, excluding the TMD which will not be wired with sensors as there isn't much point), but enough to get around half done - the outer loop and sidings then a bit of the inner loops. working also on the point servo shims which will complete that side of things nicely

[aleopardstail]

slightly more hardware development, the board has the first twin channel MERG occupancy sensor board installed, this has been basically running on its own with just the onboard LEDs as indicators - have now hooked this to a breadboard based processor - an Arduino Nano & a 74HC165 static shift register to read the inputs, currently just one but they daisy chain easily.

 

this is driving presently a paid of LEDs just to check its reading fine, wasn't expecting issues and its working perfectly, the initial pass will be 16 blocks and updating the software to manage that won't be difficult, I have some RS485 boards here as well so adding this to the C/MRI input is not thought likely to be hard. will leave as breadboard initially but likely move to a stripboard design with the eventual five shift registers on board along with the Nano and interface board.

 

amazing how simple the block detection stuff actually is, the MERG board is really quite clever