LED Flower Bracelet
I combined my passion for fashion and technology by designing and building a light reactive bracelet. This project allowed me to delve into circuit building, soldering, and the integration of electronics into fabric.
Project Type
Product
Tools
Adobe Illustrator
Laser Cutter
Electronic Components
Solder
Duration
4 Months (2023)
Overview
The challenge for this project was to develop a wearable device that is both stylish and functional, seamlessly blends technology with traditional materials, and interacts with the wearer's surroundings in a meaningful way. The bracelet's design is not only visually appealing but also functionally interactive. The green LEDs, controlled by a photoresistor that senses changes in light levels, indicate the bracelet's responsiveness to its environment and provide a visual representation of the wearer's interaction with their surroundings.
Design
The design process involved multiple iterations, beginning with initial sketches and exploring various color combinations and LED placements.
I immediately landed on felt as the fabric for its softness, versatility, and stability. Its ease of sewing made it ideal for attaching the various components later in the build process.
My idea was to sew the LEDs and photoresistor to a small piece of felt and then use layers of Heat n Bond to hide and secure the circuit between larger pieces of felt that were sized for the bracelet. This would not only bond everything together for a seamless look on the outside but also provide additional structure to the bracelet, encasing the circuit components and ensuring they remain securely in place.
Finally, I needed to incorporate the battery into the design. I came up with the idea of using a ring to secure and hide the battery pack. I had a circular battery pack that could hold a 3V battery, and the next step would be connecting the power to the circuit.
Felt flowers glued on top
Top felt piece
Layer of heat and bond
Smaller piece of felt to sew leds and photoresistor to
Second layer of heat and bond
Bottom felt piece which rests against skin
Technical Components
The circuit was the most challenging part for me, however it was incredibly rewarding to see the circuit come together over the weeks.
Originally, I only had access to red LEDs, which I used when planning out my circuit on the breadboard. I was then able to move the circuit off the breadboard, and I used alligator clips to connect the components. My original circuit consisted of a 6V battery, one LED, a Photo Transistor Light Sensor (which induces current to flow from the long pin to the short pin when light hits the internal chip), and two 1k ohm resistors.
Along the way, I upgraded my components. I replaced the Photo Transistor with an LDR (Light Dependent Resistor), eliminating the need for separate resistors and simplifying the design. I also upgraded my LEDs to Adafruit Wearable LEDs, which have two holes on the sides for easy sewing.
For the sewing, I used conductive thread to tack down the components and conductive tape to connect the circuit. I experimented with using conductive tape to attach the wires, but it proved to be unreliable and aesthetically unappealing in the long term.
Prototype And Build
For the bracelet prototype, I laser cut my design out of cardboard to establish the dimensions and make necessary adjustments. I then laser cut the felt, making the holes in the flowers slightly smaller to better cover the LEDs and adjusting the band length for a comfortable fit.
Laser cutting the felt was straightforward but time-consuming, requiring three total passes (Settings: Speed: 90, Power: 10, Freq.: 500). The teal and orange felt were made of wool, while the red felt was acrylic. Laser cutting the red felt resulted in a slightly melted plastic finish on the edges, but it was minimal and not noticeable.
Challenges
Unfortunately, while attempting to strip the wires (power and ground) for connection to my circuit (bracelet), I accidentally cut them too short. This meant that if I connected them as they were, there wouldn't be enough space for my fingers to bend and move freely, making the bracelet impractical to wear.
With the assistance of my professor and after several hours of troubleshooting, we were able to resolve this issue. We extended the wires by connecting two separate wires with pin connectors and a crimping press, ensuring a secure and permanent connection through soldering. We then soldered the newly extended wires to their respective points on the circuit (Power to the PhotoResistor and ground to the second LED). Despite this initial challenge, the soldered connections ultimately proved to be a more reliable and durable solution than I had originally anticipated.
Final Product
