Dingleberry - Small N gauge 1980's

Post pictures and information about your own personal model railway layout that is under construction. Keep members up-to-date with what you are doing and discuss problems that you are having.
aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Fri Jun 11, 2021 8:55 pm

Bufferstop wrote:Fifteen months since the first lockdown could someone remind me what the small disc on the left is for :cry:


I use them for gluing 28mm model infantry to, can't remember what they are meant to be

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Fri Jun 11, 2021 8:58 pm

on with the gibberish!

first sensor wired up, painted black and installed

IMG_2291.JPG


once its painted grey and ballasted you won't see it. will make finding them if they need cleaning interesting but there you go

on to testing!

IMG_2292.JPG


with no train present

IMG_2293.JPG


and then with a train


that bit works, code needs a bit of work on the processing but thats for another day, now the sensors actually work they can be installed and more made, actually powering them all up can come later, its just them being under the tracks thats been the delay

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Tue Jun 15, 2021 2:55 pm

more testing and some actual progress!

the two longer sidings and adjacent track block now have sensors built, tested, installed and tested again, this track is now fixed down and buffers installed with a hole drilled for some wires to drive red lights.

bit of experimentation with 0603 surface mount LEDs

IMG_2295.JPG


amazed it works, circuit board needs a bit of work though, this being designed to allow for working colour light signals

also have more of the sensor boards etched waiting drilling and assembly, which is nice

then these beauties arrived today

IMG_2296.JPG


and completely filled a siding, bought for clearance tests as much as anything else but a nice addition

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Tue Jun 15, 2021 11:30 pm

powered up to have a play

learning point: GF Mk3 coaches will run through set track points with couplers under tension (I.e. pulling them) fine but just don't try pushing them, no seriously, don't - I suspect they are just too damned light and a bit of weight would help - they do look seriously good though

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Wed Jun 16, 2021 10:04 pm

two more of the IR sensors installed and associated track glued down, have some 230VAC-DC converters coming (both 5A, one 5V and one 12V) which will see a power upgrade so I can stop heating the entire planet with a 7085 converter

more fun with the GF Mk3, I suspect the back to back gauge is a bit off as well as them needing a bit more weight - largely because they are derailing places the Lima Mk1 don't even register a track join.

will have to order a gauge at some point

aim is to get the final IR sensor added over the next couple of days and then clear the top of the board entirely so it can be sat on its end over the weekend for a bit of work, adding the power bus mostly but hopefully also replacing the point servo mounts with ones that include position switches and to start moving the control electronics to be under the surface - likely to take a few weeks at the current rate with a fair bit of flipping back and forth hooking it all up.

Additional Arduino to actually read the IR sensors and process the results have also arrived so will be doing a bit of experimenting there and designing a little sub board for them (the Arduino, headers for three sensors, a 4 pole DIP switch bank to set a device ID, three LEDs for the output and a four way header for power, ground and the I2C bus to a master unit) - will eventually have six of these talking to a 7th which in turn talks to the C/MRI bus and may also end up doing a few other bits like reading a few manual switches

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Thu Jun 17, 2021 8:35 pm

More progress, firstly the Arduino that will read the IR sensors and process the results have seen the first of their number assembled in prototype form

IMG_2298.JPG


Here we have a pair of slave units - a DIP switch allows the bus address to be changed, the LEDs are really just here for testing, these will be under the board eventually so they won't then be needed. Plus a master unit which has a small LCD screen, currently set up so the slaves have 40 "registers", each holding a 16 bit value, the master can request to read a single value, or send a new one to read.

so it can ask for a single value that will hold the three sensors as single bits (which is how it will normally work), but can also see the actual sensor values and trigger points - which it can then adjust.

The master will have the LCD and a small number of buttons that can be plugged in to calibrate things and tell the Arduino to save to the EEPROM they have, basic but nice to see it worked.

also installed the final sensor of the outer ring after replacing the sensor and re-securing a wire to get it working, this is what they are like when going in

IMG_2299.JPG


nice cut out for the sensor which is glued to the base of the track and holes for the wire droppers. Also shown is how its intended to work, train hits the sensor, which can trigger a brake signal via DCC if needed to let the train stop slightly short of the end of the block and near a signal

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Fri Jun 18, 2021 7:15 pm

Mixed bag today, firstly to show I do occasionally actually just drive the flipping trains so nice moody motion shots of one of the 86 with the Mk3 rake in tow

IMG_2302.JPG


IMG_2301.JPG


coaches behaving perfectly on the outer loop being pulled in the "correct" direction, just don't try to go the other way or gork forbit push them over points set to the curved direction. That aside very free running, both of the 86 can pull all four easily, where as three Lima Mk1 and they struggle.

Still nice to get the smell of ozone off old motors circulating again.


carrying on with other developments this has been assembled

IMG_2300.JPG


this is a small LCD, with a home brew version of the I2C interface backpack, and a second one of the PCF8574 chips talking to an octuplet of suitably hardware de-bounced push buttons, this being a test of the circuit thats intended to be converted to a PCB and given a five wire interface that can be plugged into an Arduino to give it a user interface, first usage will be to help with configuration of slave Arduino hooked to the IR proximity sensors. I wanted a breadboard version to prove it all worked.

also now have the kettle cord switched & fused panel mount socket and cable to bring a mains power connection to the board directly, the 5V 5A AC-DC converter is here, the 5A 12V one will be here hopefully tomorrow. Plan is for the weekend to see the power socket mounted up even if not yet connected and a suitable hole cut for a panel interface so the control modules can start to be moved to below the baseboard.

need to work out whats going on the panel, or cut some space to have more than one of them, so far there is:

- DCC programming track DPDT switch between programming and main track operation (I may go with a DPDT relay for this and drive it from the base station as an "output", in which case there will be an LED to indicate its state)
- USB socket for the DCC++EX base
- USB socket for the RS485 C/MRI interface
- DPDT to switch the entire track from the DCC base to an auxiliary input (to allow a DC handset to be used)
- connector for a DC socket (basically 12V DC out and track power in)
- possibly a 5V & 12V power status LED
- 20x4 LCD for the DCC++EX base station

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Mon Jun 21, 2021 9:42 pm

if anyone needs me, I'll be back at the drawing board

IMG_2305.JPG


file this under "that went well then"

I suspect a small milling table will feature in the near future

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Thu Jun 24, 2021 1:52 pm

Power supply modules installed and tested.

IMG_2309.JPG


a pair of AC-DC converter modules, 5v & 12v, both rated to supply up to 5 amps which should be more than enough. Can stop heating the entire planet via a single LM7805 now

also some relays arrived so can start to actually get all this hooked up (one will switch between DC and DCC supply to the track, controlled by the arduino managing the DC PWM controller - if the handset is plugged in switch to DC, otherwise default is DCC. The second will switch the programming track between the programming supply and the main track power feed (DC or DCC).

idea is I can run a single locomotive under DC, what with there being no isolated sections to allow the track to be used to test out new purchases prior to conversion

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Fri Jul 02, 2021 9:11 pm

Enough with electrickery for now, occurred to me when tidying up the electrical string under the board that I have a lot more to go under here, but also a lot more holes to drill..

what could possibly go wrong?

well quite, so I have decided to get the rest of the track down, gradual process as all the holes for point servos need drilling, ditto power feeds, holes for signals etc. So a mix of drilling, soldering and gluing, mixed with assembly of a few more of the IR sensor boards (have more of the boards etched ready).

IMG_2321.JPG


other half of the crossover adjacent to the main siding entrance, this will allow the inner loop to be laid round through 90 degrees to where the next turnout and blocks start. Point is in but lacking the drive servo, which will be added much later for all of these but its had the spring removed ready (which will make power on testing interesting until they are installed)



IMG_2322.JPG


prep work at the other end to provide the other bit of the second crossover and also the entrance to the MPD - this bits can then get a length of flexi cut to link them and again round the loop through 90 degrees.

circled are the little bits of plastic, using some spare glazing material, these have a small slot cut in and are glued over the 8mm diameter hole, in effect avoiding having to try and cut a small slot

will worry about actually energising it all once its installed

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Mon Jul 05, 2021 5:47 pm

Slight re-think and a bit of experimentation.

the IR sensors do work, but not perfectly, they also require a bit of mucking about in code, and an Arduino can only look after three which is not ideal.

Dingleberry is already using DCC current sensing for block detection, currently (sorry) via Analogue to Digital converters, current transformers etc. Bit of a mess, works though, mostly - can see locomotives but a vehicle with a 10k resistor on the axle and it struggles.

tried again with a voltage comparator, measurements of the voltage the CT are producing showed a locomotive at rest results in about 35mV, a coach about 2.5mV (hence why the ADC struggled) - in theory it could pick up 1.2mV, but noise confused it so it could see the coach, occasionally. A comparator can be given a 1.2mV reference voltage reasonably easily and see the coach reliably.

Well as reliably as a wheel to rail interface will ever be, its mostly about detecting things that are moving so smoothing the output works quite nicely with a capacitor, adds a very slight delay to seeing a block occupied or empty but otherwise is more reliable, a bit of code can swap for the capacitor to take "n" samples and if any of them are logic high, flag as occupied - as unoccupied is always zero here.


currently pondering swapping the IR sensors for more basic current transformers, just means adding more isolating sections and rail joiners - only have one loop and two sidings to adapt, does mean wires soldered to the sides of the rails as its mostly set track and some of the sections will be a single track section (so I can have a run of track then a smaller "end" block for it to trigger a train stop action), but I can live with that given how small Dingleberry really is.

this has the further advantage the sensors are below the board, and as long as the insulating joints are there and the dropper wires in place the actual sensors can be added later.

for some of the existing track I may just dremel a slit into the rails and just add a few more feeds, easier solution really.

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Fri Jul 09, 2021 6:12 pm

A Proper update, with actual track

While looking under the board to work out where to put stuff its obvious drilling down from above is an issue as things go in, so I decided to install the track, then drill feed holes, make sure the servos had holes drilled etc before doing more on the underside.

result:

IMG_2332.JPG


this shows the newly added inner loop along the front of the layout, plus the currently blind spur to the depot area (I've run out of insulating rail joiners so had to stop)

IMG_2333.JPG


and this is the station area to the rear, the inner loop and the bi-directional passing loop now in place, again lack of insulating joiners means the parcels depot roads have not been laid yet

none of the new points have servos and none of it is yet powered up, but a lot of the feed holes are added and more will join them when the rest of the glue has set. I've got the track to do the parcels area, though need a few more turnouts to do the depot...

next up is soldering the feed wires, which for now will bypass the current sensor system and just connect to the DCC bus and to cut some more channelling to start adding more servos, can then at least get two trains looping at once, even if the block sensor system is not currently installed.

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Tue Jul 13, 2021 2:53 pm

Another update, insulated rail joiners arrived, so today the two parcels depot roads were added, here with a triplet of Mk1 coaches on each to prove to myself they are actually long enough - though they won't take three and a locomotive - but then they were not intended to - only likely to be using one at once unless combining with the through loop road as a sort of "Inglenook for coaches" (the headshunt is shorter though).

IMG_2334.JPG


as usual still have the droppers to add in, plus suitable holes to drill, also the buffer stops need a hole for wires to a light drilling and then actually gluing into place.

only other bit I can do without a few more turnouts now is the loco depot headshunt, which even though its can't actually be used may as well be laid.

getting rapidly to the point of having to stop just dumping Arduino stuff all over now, which is not a bad thing really.

Short of the loco depot area thats the actual running lines and storage roads down now, work is ongoing on assembly of the point servo mounts, goal is all track down with all required holes drilled, will then flip it on its end to work on the underside to hook up all the droppers (each siding now has two feeds for two separate current sensors for example) - its 124.567% overkill for a layout this size but I want to experiment with techniques to later use on something larger, so overkill it is

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Tue Jul 13, 2021 8:43 pm

'nuvver bit

IMG_2335.JPG


TMD depot headshunt now added, and that really is it until more points are bought (next month), now its just adding wire droppers where needed, modifications to the outer ring for the enhanced current sensing detection methods and installing more point servos

oh, and making it actually work

I've Never had five parallel tracks before on any layout

aleopardstail
Posts: 84
Joined: Thu Apr 29, 2021 9:48 pm

Re: Dingleberry - Small N gauge 1980's

Postby aleopardstail » Wed Jul 14, 2021 5:32 pm

Card mock ups seem to be all the rage these days, and a useful tool they are.

IMG_2337.JPG


this shows the rough planned location of the retaining walls at one end, the raise bit will have a station about the two tunnel entrances (will be steel girders on brick columns, idea is to look like a cut & cover shallow job, other entrance will be the same.

red bits are where the platforms will be and the green bits a multi-level parcels depot building with street level office access and platform level warehouse access, and maybe a loading dock.

also shows the location of the single track road ramp down

a few Metcalfe wall sections thrown in for scale, can get Mk3 stock round the curves with plenty of clearance, idea is the platforms go slightly into the hidden bit as maintenance crew access with steps down

area in front of the station being mostly roadway and a bus turning area, maybe low relief buildings along the back


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