01. fabacademy

electronics design

The course started with an intense session of one hour fast non stop listing of electronic components and their characteristics on a video conference followed by the participant’s first attempts to sketch a circuit on a pcb.

The overall intention of these classes will be to gain a basic understanding of electronics design and production to at least be able to contribute in a conversation regarding the matter since my understanding of it is very close to zero.

conceptual basis

Electric charge is a basic property of subatomic particles: protons are positive, electrons are negative, and neutrons have no charge. Atoms are made of a nucleus of protons and neutrons, with electrons moving around it.

Voltage comes from an uneven distribution of electrons, creating a potential difference. Measured in volts, it’s the energy per unit charge that pushes electrons to move and balance things out.

Current is the movement of electrons caused by that voltage, and it’s measured in amperes. Direct current flows one way, while alternating current keeps switching direction.

Resistance is how much a material slows electron flow, measured in ohms. High resistance limits current, while very low resistance can let too much current through and cause a short circuit.

A multimeter is used to measure voltage, resistance, and current, and it’s especially helpful for checking continuity and debugging circuits. A breadboard is a handy solderless tool for quickly building and testing circuits.

some basic components

- Resistors: Simple two-legged parts that add resistance to a circuit.

-Capacitors: Two-legged parts that store energy in an electric field and, in this case, help smooth out high-frequency noise on power lines.

-Diodes: Two-legged parts that mainly let current flow one way, with easy flow forward and strong blocking in reverse.

-Oscillators: Circuits that produce repeating signals.

-Regulators: DC linear regulators keep the output voltage steady even if the input voltage changes.

-Transistors: Basically controlled switches, like when a microcontroller needs to turn on a bigger load such as a light.

electronics design

The first assignment was to design a board that could be used to control a set of LEDs. The board was designed in KiCad.

starting from a simple example developed in class, each of us had the task of designing our own version.

we had the chance to explore different sets and tricks to make our life easier in the production process.

the final result was a board that could be used to control a set of LEDs that was intended to have the function of a timer clock, and that could be produced in the lab.

electronics production

The second assignment was to produce the board that we designed in the previous assignment.

The production process was set to be done in the lab using a milling machine and a soldering station. The final result was supposed to be a functional board that could be used to control a set of LEDs.

To make a simple ATtiny412‑based task timer it was only necessary to add a few interface parts to the existing board.

New components required

Already in the design: ATtiny412, 5 V input, decoupling cap, 1 push‑button with pull‑down, 1 LED with series resistor, UPDI header, and an expansion header.
Missing components:
Piezo buzzer (active, 5 V, through‑hole or SMD)
Type: small active buzzer that beeps when powered (no waveform generation required in firmware).
Connection:
Positive pin → free ATtiny412 I/O pin on expansion header (e.g. PA6) via a series resistor (e.g. 100 Ω) or directly if current is within the pin’s drive limit.
Negative pin → GND.
Function: gives an audible beep at start/stop, intervals, and end of timer.

Second user button
Type: momentary push button, same footprint as your existing SW1.
Connection:
One side → 5 V.
Other side → free I/O pin (e.g. PA7).
10 kΩ resistor from that I/O pin to GND (same pull‑down scheme as your first button).
Function: lets you separate “start/stop” from “mode / set time” so the UX is clearer (for example: Button 1 cycles preset durations, Button 2 starts/stops the timer).

The production process was divided into several steps, including milling the board, soldering the components, and testing the final result. Each step required careful attention to detail and a good understanding of the electronics involved. However, the process was not without its challenges.

reflection

The final result was not a functional board that could be used to control a set of LEDs. The final steps of the production process proved to be very challenging in my particular case specifically for a collection of reasons, many of which are, to be honest external to the fabacademy course. the class itself was very comprenhensive, it went into detail on what eacch componnent does and how to use it, and the production process was well explained and documented. Personally, the bigest holdback was the fact that, not having a full understanding of the function of each component, it was very difficult to propose. This held the rest of the process back simply because I couldnt figure out what to do whith the amount of electronic components i was presented with, and i have no expertice in developoing anything like that

machine design

extruder add-on shaping module

This group project builds on top of an existing plastic extruder already present in the lab. Our goal was not to redesign the entire extruder, but to develop a complementary machine that could extend its functionality with a manageable scope for machine week. The direction we selected was a **post-extrusion shaping module** placed after the nozzle. The intention was to interact with the plastic while it is still soft, before it fully hardens, and add a new functional step to the extrusion process.

---

starting point

Our first team discussion focused on defining the kind of machine we wanted to build.

We agreed on these non-negotiable criteria:

- keep it simple
- make it genuinely useful
- keep it feasible within the available time and effort

Based on those criteria, we decided to work on top of an existing plastic extruder proposed by Max.

The extruder is based on the **Lyman extruder**, an open-source filament extruder. The machine had originally been built years earlier by previous Fab Lab members and was later recovered by Max, who reorganized the system and rebuilt it as a working bench-top setup.

*Recovered Lyman-based plastic extruder mounted on a wooden bench base. This existing machine became the starting platform for the group project.*

---

What We Decided

Once the starting conditions were clear, we froze the project direction:

- build on top of the existing extruder
- avoid redesigning the full extrusion system
- create a mechanism that adds a new step after extrusion
- keep the system compatible with manual testing first and automation after

The concept selected by the team was a **rotary shaping mechanism** positioned after the nozzle.

This mechanism was intended to:

- receive the extruded material after it leaves the nozzle
- interact with it while still soft
- shape or guide the material before it fully hardens

---

What We Built — Mechanical Development

linear axis structure

The first mechanical subsystem developed was the linear axis.

This assembly included:

- aluminum profile structure
- moving carriage
- belt transmission
- endstop switches
- stepper-driven motion base

*Top view of the first linear axis assembly, including carriage plate, guide rails, belt path, and limit switches.*

---

manual motion test

Before adding full actuation, we manually moved the mechanism to verify the basic behavior of the axis.

This test was used to check:

- smoothness of motion
- alignment of the carriage
- friction and play
- general mechanical feasibility

---

motor mount design

To integrate the motor properly into the structure, a dedicated motor mount was designed.

The part was intended to provide:

- rigid support for the stepper motor
- alignment with the transmission system
- fastening points for assembly
- compatibility with the rest of the structure
*Perspective view of the motor mount CAD model.* *Front view showing the main openings and slotted fastening holes.* *Bottom view showing the folded base geometry and mounting holes.*

---

fabricated motor mount

After the CAD design was defined, the motor mount was fabricated and checked physically against the structure.

This step was important to verify that the part fit correctly, aligned with the transmission, and could be integrated into the existing structure without issues. It also helped confirm that the design was ready for motor installation and that the motor could be mounted securely for operation.

*Fabricated motor mount plate produced from the CAD design and prepared for integration with the linear axis.*

*Motor mount installed on the axis structure to verify fit, alignment, and integration with the moving system.*

---

rotary shaping module

In parallel with the axis development, the shaping mechanism itself was developed as a rotary subsystem.

This module included:

- stepper motor
- pulley system
- belt transmission
- rotating output wheel

*Front view of the rotary shaping module, including stepper motor, pulley system, and belt transmission.* *Side view of the rotary shaping module showing the relationship between motor, transmission, and output wheel.*

---

controlling the machine — electronics and control

To actuate the machine, we assembled a small control system around a microcontroller, driver modules, and power regulation.

The electronics work focused on:

- driving the stepper motor
- reading the endstop switches
- powering the control system safely
- preparing the machine for automated motion

*Initial control board assembly used to interface the microcontroller, driver, and power electronics for the motion system.* *Close-up of the control board with microcontroller, motor driver modules, power regulation, and terminal connections.* *Handheld view of the assembled control board during testing and wiring checks.* *Control board connected and wired for operation, ready to drive the motion system and read the sensors.* ---

assembling

As the project moved forward, the different parts of the machine were laid out together on the worktable to review progress, check compatibility, and prepare for integration.

This layout included:

- the linear motion axis
- electronics and control components
- structural profiles
- rotary and transmission-related parts
- mounting hardware and small mechanical components
- tools and materials still being used during assembly
*Workbench view of the project during development, showing the machine as a collection of evolving subassemblies and components before final integration.*

testing it

First Motor Activation Test

Once the electronics were connected, we tested the basic on/off behavior of the motor.

This helped verify:

- the controller was powering correctly
- the driver could actuate the motor
- the signal path between board and motor was working
- the machine could move under powered control

At this stage, the system included the structural axis, carriage, transmission, and endstop switches needed for positional reference.

homing sequence test

After confirming powered motion, we tested the homing sequence.

This was an important milestone because it showed that the machine could:

- move automatically toward a known reference
- detect the endstop correctly
- stop at a repeatable point
- establish a zero position for automated operation

Post-Extrusion Material Test

To define the shaping mechanism, we observed the material directly at the extruder output.

This early test focused on the moment when the plastic leaves the nozzle and is still soft and deformable.

The goal was to understand:

- how the extruded material behaves immediately after exiting the nozzle
- how much working time is available before it hardens
- how the material can be guided or shaped during that transition phase
- what type of post-extrusion mechanism can interact with it effectively

This test became an important turning point in the project because it linked the existing extruder to the new machine concept through direct observation of the material itself.

It gave us a way better understanding of what the shaping add-on mechanism looked like as after the extrusion output.
*Initial post-extrusion test showing the material as it leaves the nozzle and is manually guided while still soft. This observation helped define the need for a shaping mechanism positioned after the extruder output.* ---

control interface

To operate the prototype as one coordinated system, we developed a custom control interface that combines extrusion and motion settings in one place.

The interface includes:

- machine start and stop actions
- temperature control for the extruder
- joystick-based motion input
- control of linear movement and rotation
- a simple operator view for testing and adjustment

This made it possible to manage the system as a single machine rather than as separate subsystems.

*Custom interface used to manage temperature, movement, and rotation across the system.* ---

material source

For the shaping tests, we used shredded blue plastic from failed Smart Citizen enclosure prints.

Instead of discarding these bad prints, the material was recovered, processed into feedstock, and reused in the extruder. This connected the circularity of the project not only to the machine itself, but also to the plastic being tested.

---

early shaped output

The first shaping tests produced blue spiral samples from recycled plastic.

These outputs showed that the system could move the shaping rod along the axis while rotating it, preventing material buildup near the nozzle and forming the extrusion into a controlled coil. Although still experimental, these first samples validated the core idea behind the machine.

*Early spiral samples produced from recycled Smart Citizen prints by guiding and rotating the soft extrusion after the nozzle.* ---

project poster

This is the poster we shared at the Global Review ---

problems and adjustments

During development, several issues had to be resolved:

- alignment between the extruder output and the shaping rod
- material buildup near the nozzle during shaping tests
- integrating reused subsystems that were not originally designed to work together

---

reflection

This project applied circularity at two levels: reused plastic as feedstock, and reused machine parts as the system that processes it.

Second Melt reused failed prints as material and recovered components as structure, motion, and control. The result is still an early prototype, but it demonstrated that soft plastic can be shaped after extrusion and that abandoned subsystems can be integrated into a new working machine.

---

use of ai

AI tools were used throughout the project as support for planning, documentation, interface development, and visual communication.

The main tools used were **Claude** for text-based support and **Midjourney** for

These tools were used to:

- structure the project documentation and improve clarity
- refine captions, section flow, and technical explanations
- assist with the development of the control interface code

For the control interface specifically, **Claude Code** was used as a coding assistant during the development of the machine control interface. It supported the implementation and refinement of the interface logic, including the layout and behavior of the virtual joystick controls used to manage movement, rotation, and temperature across the system.

AI was used as a design and development support tool, but all final decisions, fabrication, integration, testing, and documentation editing were carried out by the team.