Final Project — Responsive Kinetic Flower

Project Overview

This project focuses on the design and development of an interactive kinetic flower capable of opening and closing its petals in response to human presence. The system aims to simulate an organic behavior through a controlled mechanical transformation activated by electronic input.

The project integrates multiple domains of digital fabrication, including software design, 3D printing, and rapid prototyping using both additive manufacturing and low-fidelity materials such as cardboard. These processes were used iteratively to explore, test, and refine the geometry and functionality of the system.

From a mechanical perspective, the project is based on the transformation of motion, where a single input movement is distributed and translated into coordinated actions across multiple elements (petals). This required the development of a mechanism capable of converting rotational motion into vertical displacement, which then activates individual components in a controlled sequence.

The electronic system is built around a microcontroller platform (XIAO ESP32), integrating a PIR sensor as an input device and a servo motor as the output actuator. The system detects the presence of a user and triggers the mechanical response, creating a direct interaction between the environment and the object.

Beyond its technical implementation, the project explores the relationship between technology and perception. The goal is to move away from purely functional devices and instead create an artifact that evokes a sense of life, responsiveness, and subtle interaction, bridging the gap between engineered systems and natural behaviors.

Motivation

The motivation behind this project is to explore how digital fabrication, mechanics, and electronics can be combined to create interactive objects that go beyond functionality and engage users at a sensory and emotional level.

Rather than designing a purely technical device, the intention is to develop a system that behaves in a responsive and organic way, where movement is not only controlled but also perceived as natural and expressive. The project uses a flower as a medium because it represents a familiar and intuitive form of transformation, allowing the interaction to be easily understood while still offering complexity in its mechanical resolution.

This project is also driven by an interest in translating simple electronic inputs into meaningful physical responses. The challenge lies in bridging the gap between detection (sensor), decision (microcontroller), and expression (mechanical movement), creating a coherent system where each layer contributes to the final experience.

References and Inspiration

The conceptual direction of this project is influenced by artists and studios that work at the intersection of art, technology, and human interaction. These references are relevant because the project is not intended to be just a mechanical object, but an interactive artifact capable of responding to human presence in a subtle and engaging way.

• Refik Anadol — creates immersive environments using data and AI to generate emotional and sensory experiences through light, movement, and digital media.
• Random International — their installation Rain Room responds to human presence, allowing visitors to influence the environment through movement.
• Studio Roosegaarde — develops interactive installations that react to human behavior and environmental signals, combining technology, design, and public space.
• Neri Oxman — explores the integration of biology, material systems, and computational design to create responsive structures and material-driven design.
• teamLab — produces immersive digital environments where artworks react dynamically to visitor movement and presence.

At this stage, the exact mechanical solution is still under development. However, the direction of the project is clearly defined: to create a responsive kinetic artifact that merges art, design, and engineering through digital fabrication, generating a meaningful interaction between the user and the object.

Development Process

The development of the project followed an iterative process in which form, structure, motion, and interaction were explored progressively. Rather than starting directly with a final mechanism, the workflow began with a formal and material exploration of the flower, and then evolved through a sequence of mechanical tests, reference studies, and physical prototypes.

1. Initial Exploration: Static Form Study

The first stage of the project focused on understanding the geometry and visual language of the flower before introducing motion. Instead of starting with a mechanism, the process began with a static exploration to define form, structure, and modular organization.

a. Conceptual Direction

The initial idea emerged from observing natural leaf structures and organic growth patterns. These references were abstracted into a radial composition, where repetition and variation generate a complex overall geometry.

The goal was to translate organic forms into a system that could later be controlled mechanically. This meant simplifying natural geometries into repeatable and parametric elements.

b. 3D Modeling Strategy

The modeling process was developed in Rhinoceros, using a modular logic. A base petal was created and then distributed using a radial (polar array) system.

Each petal was generated using surface operations (two-rail sweep), allowing control over curvature and thickness. Although the petals share the same base geometry, their orientation changes depending on their position in the radial system.

This resulted in multiple variations of petals that together form a cohesive structure.

c. Modular Base and Organization

To organize the system, a hexagonal base was designed as the structural unit. This allowed precise positioning and repetition across the full geometry.

Each module was numbered to control assembly. Additionally, the base included a cavity underneath, improving stability and allowing better integration with the support structure.

d. Preparation for Fabrication

Once the geometry was defined, the model was prepared for fabrication. The petals were exported as STL files and organized in Bambu Studio.

Key decisions during slicing:

• Layer height: 0.12 mm for balance between detail and speed
• Material: PLA
• Thin wall detection activated
• No supports required due to controlled overhang angles

e. 3D Printing and Physical Results

The petals were printed in groups, allowing validation of both individual components and the system as a whole. Each print batch included multiple variations of the same geometry, ensuring consistency while testing orientation and surface quality.

Eeach petal required manual post-processing. Due to the thin geometry and the use of PLA, small imperfections such as stringing, rough edges, and minor surface inconsistencies were present.

To address this, each piece was carefully cleaned using manual tools, removing excess material and refining the edges to improve both aesthetics and mechanical behavior. This step was important to ensure smooth interaction between components during assembly.

After cleaning, the petals were manually heat-formed to achieve a more organic and dynamic curvature. Controlled heat was applied progressively, allowing the material to soften without deforming the structural base.

While the material was still flexible, each petal was shaped by hand to introduce curvature and variation, mimicking natural leaf behavior. This process transformed the initially rigid printed parts into expressive elements with a more organic appearance.

The final result demonstrates the transition from a purely geometric system to a more organic and material-driven form. This phase established the visual identity of the project and validated the feasibility of working with thin, deformable printed elements.

Key Learnings

• Separating geometry from final deformation allows better control of fabrication
• Modular systems simplify complex radial compositions
• Material behavior (PLA + heat) plays a key role in the final expression
• This stage defined the visual and structural foundation of the project

At this point, the project was still static, but it established the essential logic needed to later introduce movement.

For a more detailed explanation of the process, you can visit the corresponding assignment pages.

2. Second Exploratión: Internal Cable System

Once the formal language of the flower had been defined, the next challenge was to introduce movement. The first mechanical strategy explored was based on an internal cable system integrated into the petals.

The intention of this approach was to transmit force from a central point toward each petal using flexible internal elements. In principle, this would allow a single input movement to activate multiple parts at once. The idea was attractive because it suggested a lightweight mechanism hidden inside the flower, potentially preserving the organic appearance of the petals.

The development of this stage involved testing how the internal path of the cable could be integrated into the petal geometry, how tension could be distributed, and how the petals would react when pulled from the center. This required thinking simultaneously about form, routing, anchoring points, and the deformation behavior of each element.

Key Learnings

However, this strategy introduced several difficulties. The geometry became harder to control because the motion depended on flexible behavior rather than guided movement. The response of the petals was not fully predictable, assembly became more complex, and the system required too much adjustment to maintain consistency. As a result, the motion lacked the precision and repeatability needed for the project.

This first mechanical exploration was therefore discarded, but it was still useful because it clarified an important design decision: the project required a more rigid and geometrically controlled mechanism instead of a system based primarily on tension and flexible transmission.

3. Third Exploration: Petal Lifting Mechanism

a. Reference Mechanism Study

After identifying the limitations of the internal cable system, the project shifted toward the study of an existing kinetic reference. A lotus-shaped opening mechanism was used as a case study to better understand how layered components can generate coordinated petal motion.

Instead of copying the reference directly, the purpose of this stage was analytical. A printed reference prototype was used to observe how movement was distributed, how multiple petals could open in a synchronized way, and how relative displacement between levels could be translated into a visible transformation.

This study made it possible to break down the mechanism into clearer principles. First, the motion was not dependent on flexible pulling elements, but on rigid parts that moved in a guided sequence. Second, the opening of the petals was controlled by geometry and contact, not by uncontrolled deformation. Third, layering the components made it easier to separate structural support from moving elements.

The most important outcome of this stage was conceptual: it changed the way the mechanism was understood. Instead of thinking about the flower as a soft object that needed to be pulled open, the project began to approach it as a coordinated mechanical system in which motion could be distributed through structure, levels, and controlled points of contact.

b. Development of Petal Lifting Mechanism

Based on the lessons learned from the reference mechanism, a third mechanical iteration was developed. In this version, the project moved away from cable transmission and adopted a direct lifting logic.

The new idea was to use a central mechanism capable of moving vertically. This movement would then activate one point under or near each petal. In this way, the petals would no longer depend on tension or flexible routing, but instead on a defined contact relationship with the central moving structure.

A central cylindrical structure was then introduced. This element acts as the main actuator, translating vertical motion into distributed mechanical responses across the system.

The next step was to explore how each petal could be mechanically connected to a structured base. A hexagonal modular system was used to organize the distribution of contact points, allowing a radial and repeatable logic across the entire surface.

Each hexagonal cell was designed to host a vertical element that would act as a lifting interface. This transformed the system into a field of discrete activation points instead of a continuous or flexible mechanism.

Additionally, a dedicated support for the PIR sensor was designed and integrated at the center of the main structure.

The design was fabricated; however, the intended movement was not achieved. As a result, the mechanism was modified by introducing defined support points for each petal. With this adjustment, when the central mechanism rises, it pushes these points and causes the petals to rotate into a closed position. When the mechanism descends, the petals return to an open position according to their geometry and support conditions.

Additionally, a structural base was designed to support the different levels of the mechanism. Some components are fixed to this base, while others are designed with clearances and guide rails to allow controlled movement. The base also incorporates space to house the electronic components in its lower section.

Several iterations were required to refine spacing, alignment, and interaction between components. Special attention was given to tolerances and clearances to ensure that the vertical elements could move without interference.

The system was then prepared for fabrication, validating the geometry through slicing simulations. This step helped identify potential issues such as unsupported areas, excessive material usage, and printing time constraints.

This new iteration offered several advantages. It simplified the system, improved the predictability of movement, and made fabrication more feasible. It also introduced a more modular structure, since each petal could be understood as an individual response unit connected to a larger central mechanism.

At this stage, the project was still under refinement, but the mechanical direction became much clearer. The system was no longer trying to imitate organic behavior through flexible complexity; instead, it began to build that behavior through structured motion and controlled geometry.

c. Physical Prototyping in Cardboard

Before continuing with more 3D printed iterations, especially the largest parts, a low-fidelity prototype was developed in cardboard. This stage was important because it allowed rapid validation of dimensions, spatial arrangement, and assembly logic without investing additional print time.

The cardboard prototype was used to check the scale of the flower, the radial distribution of the petals, the internal space required by the mechanism, and the general relationship between moving and structural parts. Because the material was fast and easy to cut, it provided a practical way to test the system at full scale and identify geometric issues early in the process.

This step confirmed that the overall arrangement was viable and that the internal volume and radial logic were working. More importantly, it helped separate which problems belonged to the geometry of the system and which were specific to the printed parts. In that sense, the cardboard model functioned as a fast decision-making tool rather than just a rough mock-up.

Key Learnings

• Analyzing a reference mechanism helped understand how to distribute motion through structure instead of copying form.
• Switching from flexible cables to rigid, guided elements improved control and predictability.
• A central vertical actuation can efficiently trigger coordinated movement across multiple petals.
• Using discrete contact points (hexagonal grid) simplified the system and made it more modular.
• Failed iterations revealed the need for defined support points to control petal rotation.
• Proper tolerances and clearances are critical to ensure smooth movement between components.
• Low-fidelity prototyping (cardboard) allowed fast validation of scale and geometry before fabrication.

4. Final Development of Design

The final design is an interactive kinetic flower developed as a circular modular object. The structure combines a central mechanism with a set of 3D printed petals distributed around the base, creating a composition that relates digital fabrication with organic movement and visual expression.

The design is organized around a circular base that contains the electronic and mechanical components. On the upper surface, multiple petals are arranged radially, generating a flower-like pattern. This layout was chosen to create a balanced visual composition and to reinforce the organic character of the project.

At the center of the system, a mechanical actuation mechanism controls the movement of the main petal or flower element. The objective of this mechanism is to allow the piece to open and close in response to interaction, connecting the physical form of the object with sensor-based behavior.

The project integrates several Fab Academy processes, including 2D and 3D design, additive fabrication, electronics, embedded programming, and system integration. The result is not only a decorative object, but an interactive system that responds to its environment through movement.

A. Overall Dimensions

The following section presents the general dimensions of the product, which define its overall scale and spatial configuration. These measurements were determined to ensure proper integration of the mechanical components, electronic system, and structural elements, while maintaining a compact and stable design.

B. Component Structure and Function

After defining the overall dimensions of the product, the system can be understood through its individual components. Each element was designed to fulfill a specific function within the structure, contributing to the integration of the mechanical, electronic, and aesthetic aspects of the project.

C.Fabrication – 3D Printing

After completing the 3D modeling phase, the components of the system were fabricated using FDM 3D printing. This process was selected due to its accessibility, speed, and suitability for producing complex geometries such as the petal supports and mechanical components.

Printing Strategy

The system was divided into multiple parts for fabrication: base structure, petal supports, petals, central mechanism, and gear. Each component was optimized individually to ensure print quality, reduce material usage, and avoid unnecessary supports.

• The base and structural components were printed flat to ensure stability and dimensional accuracy.
• The petals were printed in a vertical orientation to maintain their intended geometry and avoid deformation during printing.
• The gear and central mechanism were printed with higher precision settings to ensure proper fit and smooth motion.

Printing Parameters

The following parameters were used during the printing process:

• Material: PLA
• Layer height: 0.12 mm - 0.28 mm
• Infill: 15–20%
• Supports: not required in most of the parts (geometry optimized to avoid overhangs)
• Wall detection: thin walls enabled

Each print batch included multiple components arranged on the build plate to optimize time and material usage. On average, each batch required approximately 2 -4 hours of printing time.

D. Post-processing

After printing, the petals will be subject to a heat-forming process to achieve a more organic and curved shape. This step is critical, as the final geometry of the petals is not fully defined in the digital model but is achieved physically.

Minor cleaning and finishing operations were performed to remove imperfections and ensure proper assembly between components.

E. Assembly Considerations

During fabrication, tolerances were considered to ensure that all components fit correctly without excessive friction. Test fittings were performed to verify the alignment between the base, central mechanism, and gear system.

This phase marks the transition from digital design to physical validation, allowing the evaluation of structural stability, mechanical performance, and integration with the electronic system.

5. Electronics Development

The electronic system of the final project is based on the work developed in the previus weeks, where I tested the interaction between a PIR sensor, a servo motor, an LED indicator, and the XIAO ESP32-C3 microcontroller. This previous exercise was important because it allowed me to validate the basic logic that will later be integrated into the kinetic flower.

The objective of the electronic system is to allow the flower to react to the presence of a person. When the PIR sensor detects movement, the microcontroller processes the signal and activates the servo motor. The servo is mechanically connected to the central mechanism, which controls the opening and closing movement of the petals.

A. Electronic Components

• Microcontroller: Seeed Studio XIAO ESP32-C3
• Input device: PIR motion sensor
• Output device: servo motor
• Visual indicator: LED
• Manual control: switch

B. System Logic

The interaction logic follows a simple input-control-output structure:

• The switch enables or disables the system.
• When the system is enabled, the LED turns on as a visual indicator.
• The PIR sensor detects the presence or movement of a person.
• The XIAO ESP32-C3 reads the sensor signal and processes the condition.
• If motion is detected, the servo motor moves between defined angles.
• This servo movement activates the central mechanism that opens or closes the petals.

C. Connection Diagram

The following circuit configuration was tested during Week 10 and will be used as the base for the final project electronics:

• PIR sensor: connected to digital pin D4.
• Servo motor: signal connected to digital pin D3.
• Switch: connected to digital pin D5.
• LED: connected to digital pin D6 through a current-limiting resistor.
• Power: Battery power system.

In the final project, this same logic will be adapted to the physical structure of the flower. The PIR sensor will be placed in the center of the petals using a dedicated 3D-printed support, while the servo will be integrated into the lower central mechanism.

D. Code Used as Reference

#define PIR_PIN D4
#define SWITCH_PIN D5
#define LED_PIN D6

#include <ESP32Servo.h>

Servo myServo;

void setup() {
  Serial.begin(115200);

  pinMode(PIR_PIN, INPUT);
  pinMode(SWITCH_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  myServo.attach(D3);
}

void loop() {
  int encendido = digitalRead(SWITCH_PIN);

  Serial.print("button: ");
  Serial.println(encendido);

  delay(200);

  if (encendido == 1) {
    digitalWrite(LED_PIN, HIGH);

    int estado = digitalRead(PIR_PIN);

    Serial.print("pir: ");
    Serial.println(estado);

    if (estado == 1) {
      delay(200);
      myServo.write(0);
      delay(1000);
      myServo.write(180);
      delay(1000);
    } else {
      myServo.write(0);
    }
  } else {
    digitalWrite(LED_PIN, LOW);
    myServo.write(0);
  }
}

Code Explanation

The code begins by defining the pins used for the PIR sensor, switch, and LED. The servo motor is controlled using the ESP32Servo library, which allows the XIAO ESP32-C3 to generate the PWM signal required to move the servo to specific angles.

In the setup() function, the PIR sensor and switch are configured as digital inputs, while the LED is configured as a digital output. The servo motor is attached to pin D3, and serial communication is initialized to monitor the sensor and switch values during testing.

In the loop() function, the system first reads the state of the switch. If the switch is activated, the LED turns on, indicating that the system is enabled. Then, the PIR sensor is read. If motion is detected, the servo moves between 0° and 180°, generating the mechanical action required for the flower movement.

If no motion is detected, the servo remains in its initial position. If the switch is deactivated, the LED turns off and the servo returns to 0°, keeping the system at rest.

E. Custom PCB Design and Fabrication

To move from a temporary prototype to a stable system, a custom PCB was designed. This allowed the electronic components to be organized in a compact and reliable way, reducing wiring complexity and improving integration with the mechanical structure.

• Schematic design defining all electrical connections.
• PCB layout with organized routing and connection points.
• Generation of toolpaths for CNC milling.
• Manufacturing of the board using a milling machine.
• Soldering of components and connectors.

F. PCB Validation

Before integration, the board was validated to ensure correct operation:

• Continuity tests using a multimeter.
• Voltage and signal verification.
• Oscilloscope measurements to observe signal behavior.
• Functional tests controlling the servo and reading the PIR sensor.

G. Electronic System Validation

The electronic system was designed to be embedded within the structure:

• The PIR sensor is positioned at the center of the petals using a custom support, ensuring a clear detection area.
• The servo motor is mounted in the lower base and mechanically connected to the central mechanism.
• The PCB is placed inside the base, organizing connections and reducing exposed wiring.

This integration transforms the system from a test setup into a functional interactive object, where electronics and mechanics operate together.

For a more detailed explanation of the process, you can visit the corresponding assignment pages.

Considerations and Challenges

• Ensuring stable power supply for the servo motor.
• Avoiding noise or false triggering from the PIR sensor.
• Maintaining reliable connections after moving from breadboard to PCB.
• Aligning the servo movement with the mechanical system.

6. System Integration, Testing and Final Prototype

This stage focused on transforming the project from a collection of independent subsystems into a fully integrated interactive object. The mechanical structure, embedded electronics, interaction system, power distribution, and enclosure design were progressively assembled and tested together as a single kinetic system.

Unlike previous development stages where components were tested separately, this phase revealed new challenges related to internal space organization, cable routing, structural alignment, movement tolerances, and accessibility during assembly.

A. Integration and Iterative Development

Several redesign iterations were necessary to improve the relationship between the mechanical and electronic subsystems. Small dimensional variations, cable positioning, and component distribution directly affected the reliability of the flower opening mechanism.

The integration process included:

• Internal redistribution of electronic components
• Servo support redesign
• Mechanical spacing adjustments
• Cable routing optimization
• Battery positioning improvements
• Structural reinforcement and alignment corrections

Initial integrated internal layout.

Servo integration and PCB positioning.

Connection between the servo system and the opening mechanism.

Switch and LED mounting features integrated into the enclosure wall.

Alignment and assembly refinement process.

B. System Testing and Validation

Multiple integration tests were performed to validate the complete interaction behavior of the prototype under real operating conditions.

The first tests were conducted with the enclosure open to observe the movement of the mechanism, verify servo response, evaluate sensor behavior, and identify possible interference between moving and static components.

Additional tests were later performed with the enclosure assembled in order to validate the complete interaction sequence and the stability of the integrated system.

The testing process allowed continuous refinement of:

• Servo calibration and movement limits
• PIR sensor response timing
• Mechanical reliability of the opening sequence
• Internal cable organization
• Structural stability and alignment
• Battery integration and accessibility

C. Final Integrated Prototype

The final prototype successfully integrates digital fabrication, embedded electronics, programming, interaction design, mechanical actuation, and portable power into a single autonomous kinetic object.

The system detects user presence through a PIR sensor and responds by activating the flower opening mechanism using a servo-controlled movement sequence.

This stage validated the complete integration of all developed subsystems into a cohesive interactive prototype capable of autonomous operation.

For a more detailed explanation of the process, you can visit the corresponding assignment pages.

7. Failures and Lessons Learned

The difficulties encountered during the process were not simply failures, but important design decisions that had to be reconsidered throughout the development of the project.

• The cable-based system did not provide enough control or stability for the movement.
• Thin printed parts failed structurally under repeated mechanical stress.
• The first versions of the mechanism were unnecessarily complex and difficult to assemble.
• System integration introduced new challenges related to internal space, cable routing, and component accessibility.
• Mechanical tolerances and small dimensional variations significantly affected the quality and reliability of the movement.
• Battery integration required redesigning the internal organization of the prototype.
• Interaction behavior changed under real operating conditions compared to isolated subsystem testing.
• Assembly logic became as important as functionality itself during the final integration stage.

What proved most effective throughout the process was:

• Simplifying the mechanism whenever possible.
• Rapid prototyping, especially by testing ideas first in cardboard.
• Using real references to better understand natural movement.
• Designing motion through geometry rather than relying on flexible elements.
• Iterative testing and continuous refinement during system integration.
• Considering electronics, mechanics, structure, and packaging simultaneously instead of independently.
• Improving internal organization to facilitate assembly, maintenance, and reliability.

8. Current Status

At this stage, the project has reached a clear level of development:

• Concept → defined
• Electronics → functional
• Mechanics → functional
• Integration → under refinement

9. Next Steps

The next phase of the project is no longer conceptual, but focused on execution and integration.

• Refine the petal design
• Build a stable final version
• Validate the complete behavior of the system

Project Timeline (20 Days of may)

The final phase of the project includes design refinement, fabrication, system integration, and documentation. Additional work was required to complete the petal fabrication and shaping process.

The workflow includes overlapping stages, especially during fabrication, integration, and validation. Documentation is developed in parallel to ensure a complete and accurate final submission.