Lighting a LEGO Modular City with Arduino – Suggestions for Hardware & Setup?

[mikimouse]

Hi everyone,

I’m still new to Arduino, but I’ve recently started exploring it for a creative project that combines two of my passions: electronics and LEGO.

I’m working on a display featuring multiple LEGO Creator Expert modular buildings, and I’d love to add lighting to each room, streetlight, and vehicle, with full control via PC or smartphone (either Bluetooth or Wi-Fi).

I’ve seen that Arduino can do amazing things with LEDs, but I’m unsure how to approach this technically. Here’s what I’m trying to figure out:
• What type of Arduino board would be best for controlling multiple lighting zones (e.g., Nano, Uno, ESP32)?
• What LED modules or drivers should I use to control separate circuits for each room or building?
• Are there any libraries or techniques for effects like fading lights, day/night cycles, or even animated street scenes (e.g., traffic lights)?
• Can a single power supply manage the whole setup, or should I split the power per building?
• Is there a clean way to wire everything without making the setup too bulky or visible?

I know there are some great plug-and-play lighting kits designed for LEGO sets, but I’m more interested in building my own solution with Arduino to learn and customize more deeply.

Would love to hear any advice or see examples if anyone has tried something similar! Thanks in advance

[LarryD]

• Welcome to the group and hobby.

• Most new people start with the Arduino UNO.

• The Arduino IDE includes sketch examples that you need to review and master.

• Once you master the example sketches, it’s time to look at State Machine and Non Blocking TIMER techniques.

• This very long thread has a dog’s breakfast of electronic ideas you might be interested in reviewing.

Share tips you have come across

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• For small wires, suggest 30AWG solid wires.

Shellac Insulated wire:

Kynar insulated wire:

[sonofcy]

One wall wart power supply for the board, no matter if UNO (not likely), NANO, or ESP-32 (Most likely)
Then, depending on whether the LEDs are just on or are Neo-Pixel style, you will have an energy budget. A small wall wart can power quite a lot of lights, but one per house has a ring to it.
Research the lights and make a spreadsheet of power per light, then just plug in the # of lights to get the total. Neopixels or individually addressable leds might catch your fancy, search out a YT vid to see them in action. I have a strip around our apartment window for a Christmas display, they go through maybe a dozen different lighting effects.

[xfpd]

@mikimouse

full control via PC or smartphone

MIT App Inventor

@mikimouse

best for controlling multiple lighting zones

ESP32 controlling WS2812 (individual "Pixels" or "pixel-strings" with zones)

@mikimouse

libraries

FastLED and Adafruit_NeoPixel are the two I use.

@mikimouse

wire everything without making the setup too bulky

I use enameled wire (same as Post #2) that I have harvested from broken PC power supplies with the ends sanded.

NeoPixels (WS2812) are a bit of a struggle at first, but then are as easy as any sketch full of function calls. Have fun.

[Grumpy_Mike]

I suggest you start off by getting a box of translucent LEGO bricks, like this one:-
Transparent LEGO bricks

You can also get a limited number of bricks that are totally transparent which are great for illuminating with multi colour LEDs.

There is a LEGO compatible system with a built in battery controlling white LEDs (On OFF Flashing) to connect to their translucent sheets, called:-
Laser Pegs
These come in various sorts of sets like the five in one shown above.

Then there are "LASER Blocks" a similar idea to the LASER Pegs but with miniature bricks.
LASER Blocks

A bit of buying advice, when buying bricks from eBay make sure they are in a an "unused condition" because they sell a lot of "used" bricks. Even if they say they are from a non smoker, I have had batches that reek of smoke and it will not wash off. The excuse they give is that they are being sold by a none smoker, but have been owned by a smoker in the past.

Also look at the nano block system. Free standing miniature blocks with lots of potential for adding LED illumination.
Nano Block clear color set

Also:-

@xfpd

ESP32 controlling WS2812 (individual "Pixels" or "pixel-strings" with zones)

I would not recommend an ESP32 as the output is only 3V3 and that is not enough to drive the WS2812 without adding a level shifter. I would recommend a straight forward Arduino Uno R3.

I would also not power them by enameled wire as this will cause voltage drops that you will find to be unacceptable especially if the strips are long.