Small Scale

Turning the real-world into an immersive and detailed Arduino-based miniature diorama city.

There’s a lot to admire about makers who spend many hours painstakingly building highly detailed dioramas. All the fine detail to ensure nothing looks out of place and all brings together a fascinating story.

A jaw-dropping city diorama we came across recently had an incredible amount of electronics to make it come to life. It had vehicles that drive around the streets and stop at the realistic traffic lights.

There were bus stops with route timetables and advertising displays, functioning boomgates and drawbridges, apartments with flickering fireplaces and movies playing on the TVs, and lights that would activate at different times of the day. Even the vehicles have working headlights, brake lights and flashing indicators. When the bus pulls up to the bus stop, the brake lights activate, the yellow hazard lights flash, and the bus’s interior light turns on, is just one example.

Even more amazing, was the rechargeable vehicles that drive themselves to the city’s EV station to wirelessly recharge.

We just had to get in touch with Arne to find out all about it.

Thanks for your time, Arne. Please introduce yourself to our readers and what first got you interested in electronics?

I'm a Product Manager for Digital Solutions in the mobility industry, based in Berlin.

I have been fascinated by electronics since I was a kid. Around the age of 13 I started experimenting with LEDs and automation of miniature models to to make them appear more realistic and interactive. So I was always on the lookout to use electronic innovation and miniaturization to incorporate functional parts into the scale models I created.

Planning and realising a model scene combines my passion for architecture, design and mobility. When I am walking through the city I see lots of details in the urban surroundings which others might don't even recognise. Details like: how are those stairs arranged in the park, how is the street light arranged, how is traffic guided through the streets, innovative architecture or how people interact with their environment. Recreating this into a miniature scene and bringing it to life in a small scale to me is a lot of joy.

How difficult is it to make miniatures?

Today I take advantage of the variety of tools to produce unique models like 3D-printing, laser-cutting or CNC-milling. This makes the model building process way more time consuming in comparison to just pick a model-kit and building it but at the same time it is so much more fun to build an entirely unique project from scratch.

When my process starts I have the idea in my head and I am researching real world examples, e.g. my electric charging station which I made fully functional for the moving cars. After I picked a real world example I am constructing a 3D-model with Fusion360 and print the parts with the resin-printer. After painting and assembling I got a unique charging station which does not exist as a model-kit.

We notice plenty of electronics integrated into your models. You are obviously handy with Arduino and electronics. Can you go into details about this?

Since I have moving vehicles which are guided by a magnetic wire, and speed and lights are controlled with rf commands from the base station over the PC, it is always the aim to let the model environment interact with the moving cars and the other way around.

The basic functionality is that vehicles stop at a red light or the day-night circle when all lights on the layout are slowly switched on and off when the next day starts again. But also more advanced interactions take place like the digital bus stop arrival displays.

Those are fully custom built with very small 0.69" OLED Displays and they are controlled with an Arduino.

The bus arrival of the electric bus is indicated through sensor signals inside the road and the displayed arrival time is switching according to the distance of the bus.

I am planning to build an even more advanced version with indications of different bus lines in the future.

Do you use Arduino to control the vehicles and models in your street scene? How does all that work?

I use Arduino and ESP32 controllers to automate different scenes on the layout. They are triggered by action on the layout (eg. a moving car) or time. A day/night shift takes about 15 minutes in real time.

During that time the PC control system triggers a lot of different automations such as the mentioned bus displays (Arduino), my advertising displays on a 1.14" TFT display with animated ads (ESP32) or a moving draw bridge (Arduino).

For illumination I am using Pixel LEDs in all of the houses and street lights. Even for the illumination for the day (white LEDs) and the transition to night (red and blue LEDs) Pixel LEDs are used like WS2811.

Can you go into more detail about how the vehicles travel around the streets?

The vehicles are mostly autonomously guided vehicles (Like the big AGVs in industrial manufacturing in the real world). They follow a magnetic wire inside the street with a small magnet on the steering axle. All vehicles have a self designed and 3d-printed chassis since the base models are stationary car models.

The 3d-printed chassis are then assembled with small electric motors and battery as well as a controller to receive acceleration and light commands.

The light commands are such as headlight/rear light, brake, turning lights or for special vehicles: emergency light or working light etc.

I am trying to hide electronic components inside the vehicles as much as possible. So that my bus still has passengers and driver included and the battery and cables are hidden in the lower part of the vehicle so that no electric parts are visible through the windows.

What is the opencar system?

The opencar system is a system to automatically guide scale model vehicles. The platform has a great community, which helps with technical problems. Although it is not a plug-and-play solution as other systems e.g. the Faller Car System. For me this is exactly the appealing part since there is not one way to implement it and has a high design flexibility, which I need for my model projects.

Were there any challenges you needed to overcome to make the circuits work?

Always trial and error. I am testing out tutorials from other makers to start with and then customize it for the need I have with a special project on my layout.

What tools do you have in your workshop that you can't live without?

The resin-printer truly has revolutionized the building process. Before that it was only possible to build custom buildings and assets for the layout with a huge effort and often not satisfying result, so you were limited to the off-shelf offering from the model-kit companies. With the ability to design in 3d-cad and print the custom parts directly at home, there is no limit in creativity and exchange with: and prototyping is so much faster and detailed.

What's your go-to software for design?

For constructing model buildings and vehicle parts I mostly use Fusion360. For laser-cutting I am using Illustrator and lightburn.

What work are you most proud of?

My latest project of the functional wireless charging station in scale 1:87 was built from scratch and I am very proud that it turned out so well. The station itself was designed and 3d-printed, afterwards it got some LEDs and fits into my layout very well. The hidden functionality underneath is a wireless charging controller which can charge vehicles which stop by. They have a charging receiver coil under the chassis and the charging process starts automatically.

When I posted the station on Instagram it gained a lot of attention (4M+ views!!) from electric vehicle experts, students or EV-drivers who discussed the possibility of realization of wireless charging of real EVs. I also got a lot of messages from students who were inspired for university or school projects to re-build the model.

A few final questions please Arne. What scale are the models and what do you plan to work on next?

I try to fit as many buildings onto the small area as possible but wanted to have enough steet complexity to simulate real traffic situations. So the buildings appear rather in scale 1:100 while the figures and vehicles are 1:87 scale. The next project will include some AI generated components to experiment on how AI-tools can help model making, I am very curious how that will turn out!