12. Skin Electronics¶
Research¶
This week's assignment began with understanding how it would differ from the wearable week. I recalled what I had done during the wearable week and first tried controlling the light of a neopixel.
I came across a designer on Instagram who showcased a video of creating clothing by directly designing on a torso using a 3D pen.
I thought about using her method directly to create something for the wrist. However, since the filament from the 3D pen is hot, I decided to take precautions by either wearing thin gloves or placing organza over the skin and working on top of it.
References & Inspiration¶
@google serach
I found a photo of someone successfully 3D printing a circuit directly onto their skin! I really want to try this too. I’d like to create something like a bracelet with individually connected neopixels applied directly to the skin... But I’m still concerned that it might be too hot to do it directly.
I consulted my Fab Lab owner, TAKE, and received advice suggesting the use of liquid bandage.
@google serach
Process and workflow 1¶
@google serach
As a first trial, cut one NeoPixel LED and connect it with code. Place it on the liquid bandage base and attach it to the skin—could this turn into skin electronics, like a bracelet?
Code Example¶
File: Arduinocode
Results¶
@google serach
I imagined a glowing, transparent petal-like bracelet that appears to exist directly on the arm and worked on prototyping it as far as I could. The way it emits light is beautiful, so next, I want to try placing an LED behind the ear to project the silhouette of the ear with light. In other words, I’m thinking of creating an ear-shaped structure formed by LEDs.
Process and workflow 2¶
To create skin electronics that adhere more closely to the skin, I decided to experiment with various materials.
I also made it so that the LED changes when it detects something—how about detecting temperature changes?
The LED changes color with temperature variations. Since it will be attached directly to the skin, I want the LED color to change based on body temperature changes.
The component you used to detect temperature changes is a thermistor.
First, I tried it on a breadboard for a trial run.
The connection for the thermistor was found in the instructions from the kit that included the thermistor.
Thermistor From UNO R3 Super Starter Kit.
Write the program for the Xiao using Arduino.
File: Arduinocode
"Pay attention to the I/O assignments of the Seeed Studio XIAO ESP32C3." Following the advice about the XIAO ESP32C3 written by my friend and Seed colleague, Matsuoka-san, I decided to proceed with the connections.
I thought of creating a base using liquid bandage for the Xiao, switch box, and LED, and placing them on top of it. This way, they can be applied directly to the skin.
When establishing connections, I experimented with various methods beyond soldering, considering factors such as the width and quick-drying properties of conductive inks, pens, and adhesives.
When I glued the Xiao onto the base made with liquid bandage, it created a hole! The LED had an adhesive backing, but it didn’t stick well. So, I decided to switch to something other than the liquid bandage base to make it adhere better to the skin. I used a printed sticker (though it was white). On top of that, I connected the circuit using conductive pens and adhesives. However, the LED stopped lighting up! Oh no! Could there be a short circuit somewhere?!
In the end, I found a transparent, cellophane-like covering for wounds at the pharmacy, which is also a waterproof film. The conclusion was that soldering was still the best method for the Xiao and LED circuits (lol). I attached it securely to the wrist with the waterproof film! It turned out to be a nice skin electronics setup. By moving the wrist, the temperature changes on the skin that touch the thermistor caused the LED to change from pink (for higher temperatures) to blue (for lower temperatures)!
Video
The circuit diagram was created using a software called Fritzing
Fin.