f a b r i c a t i o n

t h e . g l o v e

p r o t o t y p e

Based on my experience during the Skin Electronics week, I began developing the glove for my Final Project.

The process of developing the glove was not easy. I went through many iterations, trying different glove constructions and layouts to find the right solution. I made more than five prototypes before achieving the final result. For all the versions, I used two-way stretchable fabrics to ensure flexibility and comfort. The main difference between them was not just the material but also the position of the sensor connections and the overall visual design. I experimented with various ways to route the conductive paths so that all four fingers could be connected without interfering with each other. This was especially tricky in such a small and flexible surface, where overlapping lines or tight spacing could lead to short circuits or weak connections.

Another major focus was exploring different visual layouts for the sensors. I tested multiple aesthetic approaches to see how the sensors could look more integrated and refined on the glove. I eventually chose the thinner, more transparent fabric for the final version because it offered a cleaner appearance and held the connections in place more effectively. Throughout this process, I had to find a balance between the technical requirements of the electronics and the visual and ergonomic design of a wearable piece.

p r o c e s s

My first step was improving the design of the flex sensors—not to change their function, but to make them more aesthetically pleasing. I created the sensor layout in CorelDRAW, refining the shapes to better follow the natural lines of the fingers and to look more integrated and polished when applied to the glove.

Before cutting the expensive materials, I laser-cut the sensor shapes out of paper using the finalized CorelDRAW file. This paper prototype allowed me to test the fit on my fingers and visualize the positioning on the glove. Once confirmed, I moved on to cutting the actual materials: conductive fabric and Velostat. The conductive fabric was cut into narrow strips, while the Velostat pieces were made slightly larger to prevent short circuits by keeping the conductive layers separated.

By layering the materials with Velostat sandwiched between two pieces of conductive fabric, I assembled flexible and visually appealing bending sensors ready to be integrated into the glove.

To assemble the sensors on the glove, I used metallic snap buttons and silicon-coated conductive thread. The thread has a conductive core and a protective silicone layer on the outside, which helps prevent accidental short circuits. Where electrical connection was needed—such as between the thread and the metallic buttons—I carefully removed the silicone coating to expose the conductive core and ensure proper contact. The metallic buttons served both as mechanical fasteners and as electrical connectors, allowing for a clean, modular design while maintaining reliable conductivity.

t h e . b o a r d

As the main board, I decided to use the Xiao ESP32-C3 due to its small size and wireless capabilities. To make it more suitable for textile integration, I used the FabriXiao board designed by Adrian Torres, which is specifically adapted for wearable electronics. I soldered the Xiao ESP32-C3 onto the FabriXiao and began planning the connections to its pins, keeping both functionality and wearability in mind.

To simplify power distribution, I created a common 5V line on the bottom side of the board using conductive fabric. I carefully positioned it under the board and isolated it from any unwanted contact using an additional piece of regular fabric as insulation. This setup allowed me to maintain a clean, safe power system.

One of the main challenges was connecting all four finger sensors to the necessary lines—5V, GND, and individual GPIO pins—within the limited space of the glove. Each sensor required three connections, and organizing these lines without creating overlaps or short circuits on a flexible textile surface demanded careful planning. I had to strategically route the conductive paths to ensure stability, minimize interference, and maintain comfort when the glove is worn.

To manage the sensor connections efficiently, I referred to the ESP32-C3 microcontroller pinout and identified the available analog pins:

• GPIO2,
• GPIO3,
• GPIO4.

These three were assigned to the flex sensors on the index, middle, and ring fingers, which allowed me to capture continuous analog values corresponding to finger bending. I connected all three sensors to a shared 5V power line using pull-up resistors to ensure stable readings. The ground connection was shared through a single common line, carefully routed across the glove to minimize interference and avoid overlapping conductive paths. This setup allowed for a clean and modular connection layout that remained flexible and wearable while ensuring that each sensor could deliver accurate analog input to the board.

For the fourth finger sensor (on the pinky), I had to use

• GPIO6,

which is a digital pin since only three analog pins are available on the ESP32-C3. This introduced a new challenge, as the sensor's behavior had to be interpreted in a binary (on/off) manner rather than as a range of values. To make this work, I adjusted the circuit to allow GPIO6 to detect a threshold bend value by configuring the pin as a digital input and implementing a software-based solution for the pull-up resistor. This required extra logic in the code to interpret the state change accurately. Despite this limitation, combining analog and digital readings enabled me to connect all four sensors to the board without additional hardware, maintaining a compact and wearable design while still capturing meaningful finger movement data.

t e s t i n g

After assembling the sensors on the glove, I began testing their functionality. During the initial tests, I noticed that a few of the sensors were not responding properly to finger bending. To diagnose the issue, I used a multimeter to check the continuity of each sensor. This revealed that certain areas of the conductive fabric were not maintaining good connectivity, especially when the fingers were bent. The problem was mainly due to the design: some parts of the conductive fabric were too narrow and fragile, which caused unstable or broken connections under flexion. The sensor structure could not reliably carry current when the fabric shifted or stretched with movement. As a result, I had to go back and revise the sensor design.

I adjusted the shape to make the conductive paths thicker and more robust, removing one of the decorative holes in the layout to ensure better integrity and functionality. After remaking the sensors with these improvements, they provided a much more stable and responsive reaction to finger movement.

p r o g r a m m i n g

To test the flex sensors, I asked ChatGPT to generate a simple code that would allow me to monitor the sensor readings. The setup included three flex sensors connected to analog pins, which returned a range of values depending on the level of bending, and one sensor connected to a digital pin that reported just HIGH or LOW. For the digital sensor, I had to make sure the internal pullup resistor was activated to get stable readings. This setup allowed me to observe the behavior of each sensor through the serial monitor, helping me check whether the sensors were properly reacting to finger movement and if the connections were stable.

// Analog Flex Sensor Pins
const int ANALOG_FLEX1 = A0;  // Flex sensor 1 (analog)
const int ANALOG_FLEX2 = A1;  // Flex sensor 2 (analog)
const int ANALOG_FLEX3 = A2;  // Flex sensor 3 (analog)

// Digital Flex Sensor Pin
const int DIGITAL_FLEX = 6;   // D4 = GPIO6
const int LED_PIN = 10;       // Feedback LED

// Calibration (adjust these based on your sensor readings)
const int BENT_THRESHOLD = 2000;  // Analog threshold for bent state

void setup() {
  Serial.begin(115200);
  while (!Serial); // Wait for serial connection

  // Initialize pins
  pinMode(DIGITAL_FLEX, INPUT);
  pinMode(LED_PIN, OUTPUT);

  Serial.println("Flex Sensor Monitoring System");
  Serial.println("----------------------------");
}

void loop() {
  // Read analog sensors
  int flex1Value = analogRead(ANALOG_FLEX1);
  int flex2Value = analogRead(ANALOG_FLEX2);
  int flex3Value = analogRead(ANALOG_FLEX3);

  // Read digital sensor
  int flex4State = digitalRead(DIGITAL_FLEX);
  digitalWrite(LED_PIN, flex4State); // LED mirrors D4 state

  // Print all values to Serial Monitor
  Serial.print("A0: ");
  printAnalogState(flex1Value);

  Serial.print(" | A1: ");
  printAnalogState(flex2Value);

  Serial.print(" | A2: ");
  printAnalogState(flex3Value);

  Serial.print(" | D4: ");
  Serial.println(flex4State ? "BENT (HIGH)" : "STRAIGHT (LOW)");

  delay(200); // Update rate
}

// Helper function to print analog values with state
void printAnalogState(int value) {
  Serial.print(value);
  Serial.print(value > BENT_THRESHOLD ? "(Bent)" : "(Straight)");
}

As you can see in the video, the sensors do not always respond immediately when the fingers are bent, and they often take a few moments to return to their original value once the fingers are straightened. This delay and inconsistency are common characteristics of self-made flex sensors, especially when using materials like conductive fabric and Velostat. Unlike commercial sensors that are manufactured with precise and consistent properties, handmade sensors can vary slightly in pressure sensitivity, resistance, and overall responsiveness. The conductive fabric may not always maintain constant contact with the Velostat during movement, and small variations in pressure or alignment can affect the readings. Additionally, Velostat has a certain elasticity and memory effect, meaning it doesn't instantly revert to its initial state, which causes a slow return in sensor value. While these handmade sensors are more customizable and visually integrated into the glove, they tend to be less stable and require some tolerance for inaccuracy or delay in readings.

b i o . p l a s t i c

At the beginning of my biomaterial experimentation, I started with the gelatin-based recipe we had tested during Biofabrication Week. This original formula included 240 mg of water, 48 mg of gelatin, and 24 mg of glycerin. After cooking and pouring the mixture, the initial result was visually beautiful with a clean surface and a pleasant texture. However, once the material fully dried, it became too rigid and brittle. The flexibility I was aiming for was lost, making the material unsuitable for folding, shaping, or being used as a wearable or movable element. This limitation pushed me to explore new proportions and combinations to develop a material that could maintain flexibility even after drying, hold its form when molded, and remain sustainable in both ingredients and process.

Through many rounds of trials and adjustments, I created a new recipe that responded better to all the requirements. The revised and optimized formula includes:

• Water: 300 mg
• Gelatin: 38 mg
• Alginate: 1 mg
• Glycerin: 35 mg

The process begins by mixing alginate with cold water and gradually heating the solution while stirring continuously. When the mixture reaches around 30–35°C and the alginate is fully dissolved, gelatin is slowly added to ensure an even distribution and smooth texture. As the gelatin dissolves completely and the temperature approaches 80°C, glycerin is added to the mix. The entire blend is stirred continuously for a consistent structure.

Afterward, the mixture is allowed to cool slightly, stirring occasionally to keep the consistency uniform. Once the temperature drops to approximately 50°C, it is poured into a mold and left to set.

After letting it dry in the hoop for one day, I used a fan to give the bioplastic enough rigidity to be ready for folding.

This final version stays soft even after drying, is durable, and can be formed into specific shapes.

o r i g a m i

I chose origami as the mechanism of output to symbolize the movement of skin over time. Just like skin changes and folds with age, origami structures transform through precise folding techniques. The beauty of origami is that it perfectly demonstrates movement while maintaining structure, making it an ideal representation of organic transformation. Depending on the folding techniques used, origami can be integrated into various mechanical systems, allowing for controlled motion that visually mirrors the natural process I wanted to express.

However, working with paper presented a challenge. While it folded beautifully, it wasn’t durable enough for repeated movement. The servo motor’s motion quickly deformed and even tore the paper, making the structure unreliable over time. The delicate folds started to lose their precision, affecting the overall performance of the mechanism. This issue pushed me to rethink both the material and the folding technique to ensure longevity and stability.

To overcome this, I began exploring alternative folding mechanisms and materials. Fabrics with embedded stiffeners, flexible plastics, or composite materials could provide better durability while maintaining the flexibility needed for movement.

So, I started my first attempt at creating origami architecture, focusing on building a more durable folding structure. It wasn’t an easy path, as it required a lot of trial and error to find the right balance between flexibility, strength, and movement. The result was more than satisfying.

I followed the tutorial step by step:

b i o p l a s t i c . o r i g a m i

Inspired by the works of Ieva Marija Dautartaitė and Jessica Stanley I am fascinated by the potential of bioplastic origamis. The thought of using bioplastics in the same way traditional paper is folded into origami shapes is exciting, especially because bioplastics are more durable and flexible, offering more possibilities for creating dynamic, long-lasting structures. The idea of folding bioplastics into intricate forms, similar to paper, but with the added benefit of resilience and flexibility, has sparked many creative possibilities.

I’m still exploring how to fold the material effectively, experimenting with techniques like heat to make the bioplastic pliable enough for precise folds, yet firm enough to maintain its shape once set.

created by Ieva Marija Dautartaitė

What really intrigues me is the idea of combining bioplastic with paper to create an origami output that could move. The concept is to design origami shapes that open and close, or transform, powered by motors. By integrating biomaterials with paper, I can potentially create a structure that not only has the aesthetic beauty of origami but also responds to mechanical inputs, making it interactive. This could lead to an entirely new way of creating moving origami that embodies both the beauty of traditional folding and the functionality of modern materials and technology.

p a p e r . a n d . f a b r i c

My exploration started with researching textile folding techniques through online resources, particularly YouTube, to understand how heat and pressure influence material structure. This led me to experiment with Lycra, testing how it reacts to controlled folding before moving on to other materials, especially bioplastics.

I began by folding two layers of baking paper into a herringbone pattern, ensuring precise alignment of the creases to create a structured mold. Next, I placed a very thin Lycra sheet between the folded layers, making sure it was evenly positioned. Using an iron, I applied heat and pressure, allowing the fabric to take on the pattern from the paper structure.

Once cooled, I removed the baking paper to reveal the Lycra, now imprinted with a herringbone tessellation.

b i o p l a s t i c . f o l d i n g

Building on my initial experiments with Lycra, I applied the same folding technique to bioplastics, exploring how different recipes react to structured deformation. I tested two formulations: one based on gelatin and the other on alginate. Each material had distinct drying and shaping behaviors, requiring adjustments in the process.

For the gelatin-based bioplastic, I first prepared the mixture by dissolving gelatin in water with glicerine and pouring it into a hoop mold to set. After 12 to 15 hours, when it was firm but still flexible, I carefully removed it and placed it between two layers of pre-folded baking paper in a herringbone pattern. Unlike Lycra, which relied on heat-setting, gelatin bioplastic is highly sensitive to temperature, so instead of using an iron, I used a fan to gradually dry it.

The slow, controlled airflow helped the material retain its structured folds as it continued to harden. Once fully dried, the result was a bioplastic sheet with a clear, defined tessellation, demonstrating that folding techniques could successfully be applied to non-woven biodegradable materials. This confirmed that the method was effective, but I wanted to explore another formulation to compare flexibility and weight.

Next, I experimented with alginate-based bioplastic, testing two variations: one mixed and set cold, and another cooked before molding. The cooked version resulted in a more elastic and flexible material, making it a better candidate for folding. After preparing the sheet, I placed it between the pre-folded baking paper and used a dehydrator instead of a fan to accelerate the drying process.

The alginate bioplastic responded differently than the gelatin version. It was lighter, making it easier to take the shape of the folds, but it also relaxed more quickly once removed from the paper. Despite this, the experiment was successful, showing that the material could temporarily hold structured patterns and potentially be used in applications requiring flexible yet formable bioplastics.

Encouraged by these results, I repeated the process with another gelatin-based bioplastic to refine the method further. After testing different drying times and folding intensities, I moved on to experimenting with other techniques to expand the possibilities of structured bioplastics.

3d . p r i n t i n g

I explored 3D printing on Lycra using the sandwich method, where I first printed a thin base layer directly onto the printer bed. Then, I paused the print, carefully placed the Lycra over the partially printed layer, and resumed printing so that the filament adhered to the fabric. This technique allowed the printed pattern to bond securely with the Lycra while maintaining its flexibility. The result was highly successful, with the tessellated structure integrating well into the fabric, demonstrating a precise and effective way to combine 3D printing with stretchable textiles.

o r i g a m i . f o r m s

To explore another approach to structured folding, I used a vinyl cutter to score crease lines onto a plastic sheet, aiming to create precise folding guides. The idea was to weaken the material along specific paths, allowing it to fold cleanly into the desired pattern. I set up the cutter with a low-pressure setting to avoid cutting through the sheet entirely and tested different line densities to find the right balance between flexibility and durability.

However, the results were not as expected due to the choice of plastic. The material was too rigid to fold smoothly along the scored lines, causing uneven bends and cracks instead of clean creases.

c i r c u l a r . t e s s e l l a t i o n

As the next form of my origami, I chose Origami Paper Starshade, a tessellation technique often referred to as solar panel tessellation because this type of folding construction is commonly applied to solar panels in spacecraft. The tessellation pattern is designed to fold into a compact structure during launch and then unfold into an expansive array of panels when deployed in space, maximizing the surface area available for solar energy absorption.

This specific origami design has mathematical foundations, requiring precise calculations and formulas to ensure that each fold aligns accurately and the pattern functions as intended. The tessellation involves geometric principles, including the need for exact angles and proportions for folding, which must be carefully drawn and measured. The formulas used to calculate the angles and dimensions of each fold are rooted in geometry and trigonometry, allowing for a precise and functional design. More about the calculation - in this video.

At first, I tried to create the Origami Paper Starshade by hand, carefully folding the pattern using simple tools. The result was visually satisfying and gave a good sense of the form, but it lacked the precision needed for accurate tessellation. Since this structure relies heavily on exact measurements and calculated folding angles, even minor inaccuracies affected the final shape and functionality. I realized that to achieve a reliable and consistent result, the process required more precise tools and digital preparation.

To improve the accuracy, I created a digital drawing of the tessellation in SVG format, carefully planning each fold line and angle. I then used the vinyl cutter to crease the folding lines onto a plastic sheet, which made the folding process much easier and more controlled. I adjusted the cutting force to 40 in order to crease the surface without cutting through it, avoiding any cracking of the plastic during folding. This approach allowed me to produce a clean, foldable structure that stayed true to the mathematical design of the origami starshade.

After pouring the bioplastic mixture into the hoop, I allowed it to set until it reached a semi-dry stage—firm enough to handle without breaking, but still flexible enough to be shaped. At this point, before it fully dried, I carefully placed it onto the plastic sheet that had the pre-creased tessellation pattern made with the vinyl cutter. This step was crucial, as the bioplastic could conform to the folds and curves of the tessellation while still being pliable. Once positioned correctly, I used a fan to dry the bioplastic completely, helping it harden while keeping the shape of the pattern. The full recipe for the bioplastic is included in the design section. The final result is a soft, flexible material that holds the tessellation form with precision, combining structure with movement.

m e c h a n i s m

To make the mechanism, I chose 3mm acrylic and used the laser cutter to precisely cut the parts. For each mechanism, I prepared 27 leg segments and 3 base components, ensuring all pieces were uniform and fit together accurately for smooth movement and assembly.

For assembling the acrylic parts, I designed custom bolts and nuts in FreeCAD to match the specific dimensions and needs of the structure. I then 3D printed them using PLA, which allowed for lightweight and precise connectors. This custom approach ensured a tight fit and secure joints without the need for standard hardware.

To assemble the mechanism, I start by attaching the 27 individual leg pieces to the 3 base parts, all of which were precisely cut from 3mm acrylic using the laser cutter. The leg components are evenly distributed around the circular base, ensuring smooth and balanced movement. I then insert the 3D-printed bolts and nuts to securely fix the legs in place, allowing for rotational flexibility where needed.

After positioning the servo motor, I connect it to the central base to actuate the movement, and link the electronic components—including the Xiao ESP32C3 board and power source—to enable programmed motion. The entire assembly is carefully aligned to maintain symmetry and functionality.