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Tomytec Bus Automation on the Yukari layout


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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):


Stay tuned for more in the following weeks/months!


  • Like 19
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Wow just saw this and this is really cool! Love it! I can buy this system in a flash! 


Can I ask if there will be a loop to 'bring' the buses back? I mean, eventually the buses will go to the end and will need to be back in the original position ….  

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Yes. This is my track plan. The busses will make a loop at the center of the layout. The bus loop is in green, with all the bus blocks appearing as white rectangles.

I even plan to work on a switch (a servo motor that moves the steel wire to steer busses in either direction). I am also working on way to recognise them with this module: Digital RGB Color Sensor, and pasting labels of different colors under each bus.



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This is what the Main Street will look like. Seen from east towards west. The tram is at the center, with the Tomix tram track in dark grey. The bus lanes in both directions are at the extreme left and right, next to the pavement. The PCBs of the bus blocs are in green, embedded in the road which is made of styrene sheets.

From top to bottom we have:

- Evergreen 9010 0.25mm plain styrene, painted grey color, with Kobaru road markings.

- Evergreen 9015 0.4mm plain styrene. I need this because the distance between the road surface and the guide wire must be 0.60mm.

- Guide wire.

- PCB with the bus block microcontrollers, hall sensors and electromagnets.


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WOW very nice indeed! I am very impressed by the graphical representation too! Lovely to see this build up! Thanks for sharing! 

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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 block 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 my first test:



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Jaw dropping! It feels like the buses are alive! Very nice indeed! I would seriously buy this in a heart beat! Man I wished I could come up with something like this.... 

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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 🙂 


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This is breath-taking work! Surely a beautiful piece of engineering work! Cant wait to see the finished product! 

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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.



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This is just so amazing....


21 hours ago, Madsing said:



What are the small squares on the ground for? The subway/ basement entrance is pretty neat! 


21 hours ago, Madsing said:

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.




Man now you even have traffic lights! Is there anything you CAN'T make?  🙂  LOVE the lights! Will they be able to change colours? 


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8 hours ago, JR 500系 said:

What are the small squares on the ground for? The subway/ basement entrance is pretty neat! 

Trees. I will plant five trees there. The size is compatible with Kobaru MP-37B https://www.1999.co.jp/eng/10501128


8 hours ago, JR 500系 said:

LOVE the lights! Will they be able to change colours? 

I don’t know yet, but I don’t think so. This would require the installation of at least three LEDs per traffic light. More importantly, since the cars can’t move, I plan to leave the traffic lights in a state consistent with the busses moving.


Thanks for the nice comments 😀

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On 3/14/2020 at 11:30 AM, Madsing said:



Beautiful work- Do you have any plan to sell your bus controllers, or open source their design?


Also, your sidewalk work is exceptionally precise- what is the material you are using, and how are you cutting it with such tight tolerances?



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Thank you 🙂

I do not plan to sell the bus controllers, but I'd be happy to open source all design files and the software. This is not an easy project though, with several microcontrollers talking to each other, so I am still working on it. I also have issues with some busses that are too fast (I have 10+ BM-0X motors purchased over the years and some of them are really slow while others are too fast to have the time to stop on top of the electromagnet). But if you are interested, I'll do my best to help.


The sidewalks are all "standard" styrene sheets. For example:

I cut them with an X-Acto knife and/or this nice little circle cutter that my wife bought me from Daiso for just $2:




I used it a lot to scratch build these public restrooms (still unfinished):




The prototype is in Shin-Yokohama, there: https://goo.gl/maps/ApM6NJAecS1ZtJhn7


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These are more recent photos of the same area (still on my workbench):




As you can see, I had fun with the Kobaru kits (their road cones and bars) (RIP Kobaru san, I miss you):



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I'd definitely be interested down the road when you get to a point to open source it or similar- the design looks great, and easy to build- a really nice PCB design as well.


I'm going to have to find a circle cutter like that! (Effectively a protractor with a blade!)


Also, I've been doing some work with the bus system, but haven't found any hard numbers and had a few questions-
- where did you find the 0.6mm guide wire depth?

- on a similar topic of documented numbers, what did you find the minimum turn radius is? I've been experimenting manually, but my results seem to be all over the place (poor test conditions, and 've yet to find good wire that the magnet wants to follow)


Thanks for all the tips!

  • Like 1
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