Today, I tested the Modellbahn Union J00002, 8-way DCC switch decoder WD8K for two-pole switch drives with screw terminals.
www.modellbahnunion.com/HO-gauge/8-way-DCC-switch-decoder-WD8K-for-two-pole-switch-drives-with-screw-terminals.htm
​It performed very well with my Z21 and Tomix switches. The operation is reliable and smooth. The PCB is very compact and allows to connect eight switches.

A few years ago, I purchased this kit from World Kougei
プラシリーズ Nゲージ TMC400A モーターカー 組立キット
world-kougei.com/SHOP/6044380.html
It's a mixed ABS resin / photo-etched parts kit. It didn't look too difficult to assemble.
I started by doing some research about the prototype and found quite a number of photos and videos online. I was immediately attracted by the Totetsu white/yellow/grey livery, photos are available here:
mcdb.sub.jp/forums/topic/fhi_tmc400a_43_東鉄_4012/
I also found a video showing operation with two locomotives, and several sets of headlights and alert lights flashing. I decided to try to reproduce that scene. 

That's what the kit looks like.

​I started by applying an undercoat of Tamiya 87044 Fine Surface Primer for plastic and metal (white), on the photo-etched and resin parts. That seemed to give a good result, but as I will describe later, during the assembly the paint started to peel off from the photo-etched parts. That has been a huge issue. I usually use Tamiya 87061 Metal Primer, which works very well, I should have sticked to this one for this project too.

​Gluing the parts was supposed to be easy, but proved very difficult at first. I tried Tamiya 87182 Extra Thin Cement, which didn't work at all. Of course the Tamiya Craft Bond works but it is very thick, very slow to dry and not very strong. I ended up using standard CA glue, which works well but is too fast, no time to adjust the parts... Next time I will try Tamiya 87137 Cement for ABS.

Painting white and grey worked quite well. I then looked for the perfect yellow for the project. I tried AK11046 Radiant Yellow, AK11047 Lemon Yellow and AK11049 Fluorescent Yellow from AK-Interactive. These bottles include dispensers and the paint is ready to use with a brush or airbrush. I decided to go with AK11047 Lemon Yellow.

​I cut, weathered and pasted small rectangles of AE03 Metal plate anti-slip 90 for the sides.
www.finemolds.co.jp/www/list/listetc.htm
That was not too difficult to make and this is a nice improvement to the model. However, this made attaching the side fences much more difficult as I had to drill new holes for them.

I then started to experiment with LEDs for the various headlights. The plan was to make a small DCC decoder with 5 LED outputs, and connected the LEDs to it. 0402 Warm White LEDs for the head and tail main lights. 0201 White LEDs for the side lights. Various 0402 orange LEDs for the alert lights. I installed a total of 12 LEDs, and ended up with an unmanageable web of wires... impossible to solder to the DCC decoder.
I then decided to make another PCB just to manage the connection to the LEDs. That proved a good idea, but the whole thing is still very difficult to assemble and very fragile. Not recommended.

This is a photo of the EM13 decoder connected to the motor.

Anyway, I pushed through and made it work. So I now have 3 PCBs in this tiny cabin. The EM13 for the motor, the self-made DCC decoder for the lights, and another PCB right below the roof for connecting the LEDs. That's very difficult to manage. As I fell in love with that locomotive, I am now planning to redo it (next month, next year, or next life).
- The motor decoder is not necessary, the locomotive does not run well at low speed anyway, it would require at least a flywheel and a keep-alive.
- I plan to redo the lamp DCC decoder to fit it right under the roof and solder most of the SMD LEDs directly on the PCB, using 3D-printed light pipes. That would hopefully make the wiring much more manageable.

This is the final result before installation. I have fitted a small SMD LED inside the signal. I'm happy with the result. The dots forming the digit are neat (although they are just 0.3mm in diameter).

I decided to 3D print shunting route indicators to test the capabilities of my 3D printer. I designed the 3D models in Autodesk Fusion 360.

These are the first results

Even the digit indicator printed nicely.

Installation and additional photos

The spectacle shop, step by step construction

Lighting the staircase 

Making of the signboard

I have used a new process for the signboards of the Japan Post building.
The case has been 3D-printed. The light comes from a new type of COB LED light strip. It is very narrow (2.7mm), can be cut every four LEDs, and the LED density is very high (480 LEDs per meter). It can be purchased from AliExpress here:
www.aliexpress.com/item/1005003193200776.html

On the layout, I use an LED control system described here: https://shin-yukari.weebly.com/led-controller.html. It is based on Adafruit 12-Channel 16-bit PWM LED Driver modules spread all over the layout. They allow a central computer (a Raspberry Pi in my case) to control the hundreds of LEDs fitting the various buildings.
In addition, I needed a similar control box on my workbench. This is a description of the system I have designed.

It uses the same Adafruit module and exposes the 12 LED outputs on terminal blocks with push-in connection, suitable for temporary connection (no soldering required, no screw).

Here we see a building "under construction", with its wires attached to the control box.

I have designed the PCB in Autodesk Fusion 360. The system is based on an ESP32 microcontroller connected to the Adafruit module and to the various connectors and terminal blocks. The ESP32 exposes a web page used to individually set the brightness of each LED.

Next up, the vertical signboard

Each storey is lighted individually, using small light boxes.

I needed to add more signals, so I made a new version of my Arduino Nano-based DCC signal controller. This one can control up to ten Tomix signals. 

​Working on the construction site this week.
First, new signboards and decals

​Two years and five months ago, I managed to control a Tomytec bus by using an electromagnet under the road. I am now happy to report that I have finally been able to move the modules of the main street, bus interchange and Iwasehama station to the layout. All the wires for the bus control blocks, the hundreds of LED lights, the signals and the tracks are connected and everything seems to work fine. Well, not everything. There are still so many things to improve. These buses sometimes seem to have a mind of their own!
Next (major) step: finish the tram layout, and make sure that trams and buses don't collide! For that, I'll have to teach the Raspberry Pi Python application controlling the buses to talk to Rocrail! Interesting challenge.

​- TFT display is 320x240 (240x320 portrait) ILI9341
- I use fbtft_device to drive the display
- The video is a h.264 mp4 file played by mplayer

​Hardware components used:
* ESP32 (Lolin32) with 4BM Flash memory
* Tourist Information: 0.96" 80x160 RGB IPS display with ST7735 driver (only the top 80x80 pixels are used and visible)
  
  Connections:
  DISPLAY      ESP32
  --------------------
  GND            GND
  VCC             V3
  SCL             SCL       (SPI Clock)
  SDA            MOSI     (SPI Data (to slave))
  RES            GPIO4    (Reset)
  DC              GPIO2    (Data/Command)
  CS              SS/5      (Chip Select)
  BLK            GPIO15

Uploading files to the ESP32 flash:
Install ESP32 Filesystem Uploader in Arduino IDE
https://randomnerdtutorials.com/install-esp32-filesystem-uploader-arduino-ide/
https://github.com/me-no-dev/arduino-esp32fs-plugin/releases/

The size of the ESP32 SPIFFS partition can be set in the IDE as 1Mbyte or 3Mbytes.

Place the video/image files inside the sketch folder, in a folder called "Data".  Then upload all the files in the folder using the Arduino IDE "ESP32 Sketch Data Upload" option in the "Tools" menu.
​
The sketch loads
- an 80x80 pixel background image (back.jpeg) once at the beginning
- a sequence of up to one thousand 40x80 images (videoNNN.jpeg) stored in the built-in flash memory.
  
The videoNNN.jpeg files are built as follows:
- Scale and crop the source video to 40x80 (portrait) with Handbrake
- Extract the .jpeg files with ffmpeg:
    ./ffmpeg -i video.mp4 -s 40x80 -r 10 video%03d.jpeg

Trying to fit 0402 LEDs into Kato 23-214 traffic lights. It works, but I am just going to install one LED (either green or red) in each signal.

​This is where the bus guide wire crosses the tram track:

​Next step: the bus interchange. I have built a switch for the bus: a servo motor moves the guide wire towards one of the two positions.

​It works 🙂 

Today, I have started the integration of the system into the python application that runs on the raspberry pi (the same one that controls all the LEDs on the layout).
I have added a screen to control the busses, it looks like that:

Each bus block is a white rectangle. The block is highlighted

• in red if there is a bus arriving or stopped inside
• in yellow if the bus inside has stopped because of a traffic jam
• in green if the bus is departing

For bus blocks that are bus stops, there is a timer that shows how long the bus will stop there.
The application makes sure that there is no collision. The video below shows the results of very the first test:

For more than a year now I am trying to control the Tomytec busses (fitted with a BM-01, BM-02 or BM-03 motor). My ultimate goal is to make the street at the centre of my layout look like this:

There will be

• Two bus lanes (one in each direction), with busses following each other and queuing at the bus stops and traffic lights.
• Two car lanes, with all cars stopped because of the traffic.
• The tram lane at the middle.

I have made significant progress in the past weeks and I am now able to

• reliably detect the busses using hall sensors (placed just below the guiding wire)
• stop the busses using electromagnets on the right side of the guide wire (the Tomytec busses detect the magnetic field and stop until it is switched off).

Under the bus lane, I will place “bus block” control units (I have built twenty of them so far) wherever I want the bus to (potentially) stop. This is what two bus blocks look like (seen from the bottom):

They will all be connected to a Raspberry Pi, which will be able to control the traffic flow.
All of this is still under development, but this weekend I have been able to connect eight bus blocks, and this is the result (that I find really encouraging):