B3S Building Block Breadboard System

Building Block Trainer Board

Whether for electronics crafting, self-study, training courses, or school, this is a universal system for building individual boards

The Idea

After discovering the YouTube video channel Attractor, which by the way is highly recommended, I had the idea to make breadboard setups a bit more professional and stable. After numerous concept ideas and failed attempts, this system finally came into being months later

Yes, I invested a lot of time and filament to bring it into its current form

The Principle

The modules are designed on a 36x36 mm grid, which in my opinion is the best compromise between compactness and ease of assembly

Most modules are housed in a carrier box (BB-25-02-xx). The entire electronics are attached to the insert

This not only allows for easier assembly but also enables the inserts to be rotated as desired. This means you can attach the box to any side of another box and still rotate the insert to ensure optimal usability

For control elements like switches and potentiometers, the labeling and the element can also be freely rotated in 90° increments

All modules have been optimized with wiring in mind, so that with careful construction, short circuits are practically impossible even after prolonged use. For this reason, Dupont sockets are also used as connectors. These also offer the advantage that the wiring on the board corresponds to that of the modules, meaning no special cables are needed

The modules are divided into the following groups:

• Breadboard
• Power Supply
• Output elements such as LED
• Control elements such as buttons, potentiometers, and switches
• Microcontrollers (as a separate MakerWorld project)

All power supply modules and all output modules are designed for mounting above the breadboard and always have the positive connection on the left and the negative on the right. Similarly, the input is on the left and the output is on the right, if there are inputs and outputs

A Personal Note

I am making this model freely available here to open up new possibilities, especially in the field of education, where funds are always limited. As mentioned, you can download this model here for free, but you must adhere to the rules

The Rules

• It is **not allowed** to **sell** the model files or printed parts made from them, or to market them otherwise for profit!
• It is **not allowed** to share or publish the model files or documentation! Always share the link to this page. This is the only way improvements can reach users.
• It is **allowed** to make as many prints as you need, especially for your students!
• It is **allowed** to publish pictures of your prints with a link to this page.
• If you provide feedback, which I would greatly appreciate, but do not give 5 stars, please write what you dislike or what you would improve. 4 or fewer stars without a comment are disrespectful; they benefit neither me nor others. With an appropriate comment, 1 star is, of course, also okay :-)

Printing

The easiest way is to use the attached print profile. Unneeded parts can be hidden under “Objects” in Bambu Studio by removing the green checkmark

This model contains a number of small details and fits, so it is essential to calibrate the filament properly and to thoroughly clean the build plate beforehand with soap, warm water, and a brush. A new textured plate can be scrubbed with steel wool (e.g., with integrated soap) to achieve much better adhesion

I had already published the potentiometer knob

Now blocks for RP2040 and ESP32-C3 are also available!

Colors

Of course, other colors also look good! You can quickly change this by simply changing the color of the respective filament. If you want to color individual parts differently, this is also easily possible

1. Select the part by clicking on it with the mouse (e.g., the LED holder for two LEDs)
2. Rotate the board so you see the underside
3. Zoom until you see the marking large
4. Click the paint bucket
   

5. Select paint bucket and edge detection
    

   

    

   Now you can hover over the symbols or text and color them with the selected color.

Parts

Here are a few AliExpress links to the parts I used. No guarantee that these are the cheapest offers, but I was satisfied with the quality

• Breadboard
• Rectangular switch
• Toggle switch On/On (can also be used for On/Off, of course)
• Potentiometer, depending on the application, I recommend 100kΩ or 10kΩ
• RGB LED Common Cathode
• Dupont cables, female-female
• XL1509 Step-Down Converter with adjustable output voltage

I receive a few cents commission if purchases are made via these links

Assembly

The assembly of the individual functional blocks is hopefully explained in sufficient detail with pictures in the attached assembly instructions

Wiring

For wiring, I recommend ready-made female-to-female Dupont cables. These are cheaply available everywhere and save you the not-so-simple task of crimping

These cables can simply be cut in the middle, and you'll have pre-assembled cables for one or two boxes

For the power supply connection, I recommend soldering a 100µF electrolytic capacitor and a 100nF ceramic capacitor in parallel with the terminals inside the box. This prevents interference voltages, especially with longer supply lines

Cost for a Trainer Board

In my experience, a board like the one pictured can be built with less than 10 Euros worth of materials. The parts are available from common electronics retailers or on AliExpress. If you already own an experimentation kit, you probably have most of the parts and the cables already

Tips

• Don't use the cheapest breadboard; they usually have very poor contact springs.
• For wiring, use tinned wire with approximately 0.6 mm diameter. Copper wire quickly forms a corrosive layer, which makes your circuit unreliable. I've found lengths of 3 cm, 5 cm, and 7 cm to be quite universal.
• Dupont cables have a square contact, which can wear out the contact springs in the breadboard if not inserted carefully (straight).

Final Word

I wish you much joy with your individual trainer board and would be happy to receive feedback, preferably with a picture. Of course, I would also appreciate a like or boost!

Updates

17.11.25 A module for rectangular switches, a module for round buttons, and an empty module as a spacer

20.11.25 New module for a half breadboard, updated assembly instructions, base with small update to version 1.1

22.11.25 XL1509 Step-Down Module

24.11.25 RGB-LED module for common anode and for common cathode, minor updates to the LED modules. Updated assembly instructions.

04.12.25 Servo SG90 module added, assembly instructions updated to version 1.4, minimal improvements to various modules

28.04.26 Base and half base modified to reduce the formation of a “waterline”. Print profile updated.

18.06.26 Significantly improved connectors on all boxes. New, optimized print profile.

All B3S models can be found in the B3S collection

If you like this model, you might also like other models from me, e.g.:

Microcontroller blocks	Breakout board holder	LCR-T4 Case	Wire Holder (different variants)	Potentiometer Knob