Collaborators: Oriana Neidecker
As mentioned in last week’s midterm brief, I am interested in wearables, soft circuits, and movement; and my partner is interested in wearables as well -particularly those that aid the wearer’s health.
Our Goal for our midterm project was to make a necklace that measures various vitals of the wearer, ie temperature, heart rate, etc. and displays fun, ambient lighting until set thresholds are passed for each vital being read. Once the threshold is passed, the necklace displays a different signal that alerts the friends of the wearer that their friend should be watched over. If additional thresholds are passed, the lighting of the necklace changes with increased urgency until all lights on the necklace are blinking urgent red, signifying that the wearer is in need of immediate medical assistance.
What We Actually Did Create We succeeded in creating a soft circuit necklace that accurately reads the temperature of the wearer and displays flashing red lights (as opposed to ambient mood lighting) whenever the wearer’s temperature exceeds a set temperature threshold.
What Got Left Behind For ease of use, we decided to limit the readings being taken by the necklace (or choker -so trendy right now) to temperature alone. We also limited the stages for the lights being displayed to simply “having a fever” or “not having a fever”. We did this for a few reasons:
- We were warned by several sources that the lilypad pulse sensor we were planning on using was notoriously temperamental. (Indeed -even the most advanced products like the apple watch still have trouble reading pulse).
- Unforseen complications with our code discouraged us from spending more time on it, and we decided to kill our darlings in favor of producing a better finished product.
II. THE PROJECT
Materials & Tools
–Felt, Velcro, Hot Glue Felt is the most forgiving fabric to sew conductive thread. We used a simple velcro attachment in order to easily remove the front of the choker.
-Conductive Thread We used 3 ply adafruit medium conductive thread, which was the strongest, thickest thread that was still relatively flexible.
-Neopixels We decided we wanted to work with neopixels as opposed to dumb LEDs, and that we wanted to do so with individual neopixels as opposed to using a strip; this offered more versatility in the form and also lent itself to a greater understanding of the neopixels themselves.
-Microcontroller We wanted to use a Lily Tiny (pictured below) but our project would work with any microcontroller with analog output/digital input capabilities.
-Lillypad Temperature Sensor This was the smallest wearable sensor we could find on the market, and our research told us it was reliable.
We also soldered our sensor to stranded core wire from the output for a more accurate read:
-Wire Strippers, Foam (for prototyping board), Solder, Alligator Clips, Wires, Stranded Core Wire We needed stranded core wire for its flexibility and in order to sew
Of Note We learned we needed to download the neopixel library in order to run various strand tests and start programming the neopixels. We also had a few learning moments when it came to doing things like:
- tripple checking your port
- selecting the proper microcontroller
- reviewing the types of microcontrollers that best serve your project before ordering them because…
Our lily tiny microcontroller wouldn’t work.
I just wouldn’t. We scheduled sessions with two different residents and they couldn’t get it to work either. Lesson learned: research your parts to see whether a) the community that uses said controllers have good things to say about it. Something like “this microcontoller works and I like it because it’s also easy to use” would have been perfect.
We decided that once we got out neopixels up and running, and that we were acquainted enough with the code, it was time to set up our prototyping board. This is what it looked like:
Here’s a video of our working prototype:
Transferring To Wearable
Now that our prototype was working, it was time to transfer the prototype to our wearable. This involved careful planning:
Transferring the prototype to the wearable was probably the most challenging part of the project. It involved many false starts, redos, and tons of conductivity testing:
Finally, it worked:
Pro Tip Don’t wear a necklace under your choker:
But now it’s working.
What We Learned
Hey! Wearables are difficult. Conductive thread, though super flexible and even pretty to see from a design standpoint, is not always the most reliable medium.
If I were to start this project over, I think I would have definitely made a point of researching the types of sensors I was going to use more extensively beforehand. Though our sensor worked the majority of the time, it would also get overloaded and start spitting nonsense on our reader.
On the whole, I am definitely more comfortable with soft fabrication now. Particularly with conductive thread and sewing soft circuits, and also converting those soft circuits to hard circuits. I also learned how to solder!