StressBracelet

Context

Life in the city requires a constant chase against time. From long demanding hours at work to brief hours we spend relaxing with family and friends. This anxious chase, while it might boost productivity for some time, is not sustainable for the body of many people, like me. I find myself overwhelmed, whether it’s the crowding or noise, and I tend to regularly and physically isolate myself from my surroundings to meditate and slow my heart rate and eventually my anxiety down.

 

Brief Description

StressBracelet is a biosensor that uses galvanic skin response to measure the stress or anxiety level and responds with the lighting of 12 LEDs when stress levels are high. The user of this device would wear the bracelet and go about their day as usual, if the LEDs switch on, or if the user can feel their anxiety rising, they can take a break and do some meditation which would lower the stress and that would lower the moisture in the skin, which in turn switches the LEDs off.

The idea behind this bracelet is that since we, as city dwellers, are all prone to stress, there is a need for a device that silently communicates with us our level of stress is high, and if needed, that we should take a few minutes to breathe and take control of it. Using colourful LEDs added a positive spin to this device, on one hand, the user might be experiencing anxiety, but on the other hand, they will also see a colourful mixture of light, which is a less stressful approach to interact.  

 

Link to the video

 

Objective

The aim of this experiment is to propose a tool that would help people get rid of their anxiety in public spaces and especially on their commute. The sensor has to be easily portable and accessible on-the-go, while at the same time discrete and personal in its interaction.

Design Process (Documentation)

The reason I decided to create this sensor in a bracelet is because it is important for this device to be handsfree for people to use while they are walking or commuting. I am also interested in bringing to the table the concept of electronic components as a wearable statement that speaks to a digital generation. So, starting from this logic, I began to think of how a bracelet like this might look. Chain bracelets are some of the most popular bracelets used worldwide, whether made of silver or gold, chain designs have been the dominant style for bracelets for a long time.

A sketch of the bracelet in the chain link design
A sketch of the bracelet in the chain link design
A sketch of the LEDs wiring for the chain link design
A sketch of the LEDs wiring for the chain link design
The updated design for the bracelet
The updated design for the bracelet

So, building on that, I decided to experiment with the idea of chaining LEDs create a chain that is then connected to a controller, which then adds a certain functionality of the chain. However, I quickly realized how difficult it, because of the number of wires required to connect the LEDs to the 5V and the ground. So, I decided to tweak my idea and create a different iteration of the bracelet with the LEDs attached to it, rather than hanging from it.

Once I built the circuit, I added more LEDs following the same logic
Once I built the circuit, I added more LEDs following the same logic

For the finger sensor, I decided to use aluminum foil attached to velcro and wrapped around two fingers, index and middle fingers. Although the foil is sufficient for this experiment, it is extremely fragile and cannot be constantly re-used. However, through experimenting with the sensor, I recorded the serial readings and noticed that they were extremely unstable, but I was able to get an idea of the range, between 0 and 13 in a normal state, and 15-28 when activated. The experiment I made used meditation as a way to push moisture in the hands (from sweating due to stress) down and blowing hot air into them to activate the sweat glands and record higher readings. Through moisture in the hands, the voltage on the serial print through the Arduino is either increase (with more moisture) or decreases (with less moisture). This allows us to record those readings and measure to some extent the amount of stress a person is going through.

 

The end result of the experiment
The end result of the experiment

To build the circuit I followed a similar approach like the one we covered in our last experiment. Connecting one of the sensors to a transistor that is also sending the sensor value to the A0 pin, and the other to the 5V pin on the Arduino. Also, linking the LEDs to digital pins on the Arduino and the ground to the ground. This circuit allows the Arduino to read the amount of voltage that passes through the human skin, which increases when the sweat glands are activated through stress, anxiety, working out, etc.

 

Fritzing sketch of the circuit
Fritzing sketch of the circuit

Once all the parts were assembled, I moved to the Arduino code. I started off from the provided code in the class presentation slides, which only gave us the ability to control one LED. So, I decided to add 11 more LEDs in order to achieve a sort of ambient effect as a result of the rise in the stress level. In the code, I assigned pins 13 to 2 (with the exception of 10 and 23) as LED pins and connected the positive side of the LEDs to the digital pins on the Arduino. Also, I knew I had to add the “digital.write” line of code for the 11 new LEDs .

Link to the Arduino Code


Tools & Materials Used

12x LEDs

1x Arduino Mega

1x 330 ohm transistor

2x aluminum foils

2x pieces of velcro

 

Challenges

The biggest challenge I faced during this experiment was figuring out how to make all the components fit into a wearable device. One of the problems is I only own an Arduino Uno and Arduino Mega, and both are way too large to be considered for wearables. However, having a smaller controller will make this task a lot easier. Also, my original idea of connecting the LEDs and the components in a chain link turned out to be much more complex than anticipated, which led me to change my design drastically.

I am considering other options of how to put this device together for a wearable experience.

 

Future Steps

During my research into different ways to make this device, I noticed that some people were able to build something very similar without the use of a controller. I am very interested in pursuing that option further and seeing where that would lead.

For this experiment, I used parts from my own collection, however, for my next iteration, I plan to purchase a few parts in order to tweak the device even more.

Learning how to build a biosensor opens up many doors for future explorations into this subject. We can build and customize our sensors to match our bodies.

PraTattoo

Overview

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Tattoo practicing can be extremely frustrating because it’s difficult to find people who are willing to volunteer their skin for beginner tattoo artists to practice on. So, many artists start with fake skin, which is a tattoo practice sheet made of silicon. A very popular starting point, which might not be very good because it has no indication on whether the student is doing it right or wrong. I’ve been to many tattoo conventions and most tattoo artists I met are self-taught, which is usually a very long process because of a shortage of volunteers and lack of direction. I remember when I was starting to use fake skin sheets for the first time, I had no idea whether the needle was going too deep or too shallow, which can be problematic because the whole point of the practice is to build the correct muscle memory.

So, I want to use this experiment as an opportunity to explore how to extend the tattoo practice sheet to a more reliable tool for new tattoo students. The sensor I created allows the students to tattoo on the practice sheets while the tool is indicating levels of pressure: green for “okay”, yellow for “a little too hard”, and red for “too much pressure”.

 

Video

https://youtu.be/bqZh3BMCpn0

How it works

When the tattoo student is ready, they will hold the machine as they would normally and start tattooing. It is vital to know the correct angle to hold the tattoo machine at because tattoo ink is supposed to be pushed by the needle into the Dermis, which is the second layer of skin we have under the Epidermis (top layer of skin). If the ink is not pushed far enough in, it will not stick and eventually will be pushed out by the skin. However, if the ink is pushed too far deep in, past the Dermis, the ink will be spread out too much and ruin the quality of the piece. So, it is vital for the tattoo artist to train their hand muscles to memorize the movement and the angle, with continuous practice, accurate muscle memory is achievable.

So, after the tool is assembled, with all the layers in the right order, the green LED will be lit. As long as the machine is held in the right angle, and the pressure on the needle is not too high, the green light will indicate that the student is on the right track. However, once the yellow LED is lit, the student has a chance to fix the gesture back to the green zone. Red LED is an indication that the pressure is too high and most likely it would’ve caused some bleeding on human skin.

Documentation

First, I started with filling the measurements sheets, which is great because I was able to test the different values of the conductive textiles we received in our kits. This allowed me to see the variations between the values “at rest” and “activated” before I start building my sensor.

These are the values received on the multimeter
These are the values received on the multimeter
These are the values received on serial using Arduino
These are the values received on serial using Arduino

I tested the different textiles to see which would work best for my sensor, and I realized that, out of the textiles in the kit, the Velostat worked best for this tool.

 

Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances
Testing the conductivity & resistance on the Eeonyx Conductive Fabric at different distances

Video of the test

Next, I started sketching different variations of what that tool might look like. As a tattoo student, I have some insights into what I believe how this tool should be used and how it should look like to effectively perform its intended function. On the other hand, this is a speculative approach, and I was open, throughout the process, to changes and modifications to the concept.

In the initial sketches, I was planning to use a regular foamboard for the back support, with conductive fabric and Velostat sheet between the back and the front layers. When I built this prototype, I quickly realized that without proper support, this device will not be functional as it’s supposed to, because the layers will constantly move which will cause unstable values.

A side view of the layers
A side view of the layers
A separate view of each layer
A separate view of each layer
The order of the layers
The order of the layers

For my second prototype, I decided to use wood as back support with four pins on each corner to hold each layer down in its place. The reason is that wood is not conductive, and since the wooden pins will be holding down every layer, a conductive pin can cause shortcircuiting and/or inaccurate results.  

My first test to use the silicon sheets
My first test to use the silicon sheets
When I added the wooden platform with the pins, I ran another test to make sure things are still working
When I added the wooden platform with the pins, I ran another test to make sure things are still working

Video

Once I had this prototype completed, it was a matter of tweaking and fine-tuning the parts in order to get the intended results. So, moving to the LEDs, which are essential to this tool’s function, was relatively an easy process. I used the generic 2-pin LEDs in 3 colors, green, yellow and red.

Final Test
Final Test
Using an Arduino Uno, this allowed me to use the controller for most wires, but eventually I had to use a small breadboard
Using an Arduino Uno, this allowed me to use the controller for most wires, but eventually I had to use a small breadboard
Once I added all the electronics, I ran another test. However, this time, the values I got on serial were different
Once I added all the electronics, I ran another test. However, this time, the values I got on serial were different

Although the tool I created is an early prototype with a lot of wires showing, I made sure that it is stable and portable. However, for my second prototype, I am planning to create a shell for all the parts, and soldering all the parts together in order to make sure it will last over long use.

The view inside the control box, you can see the resistor used for the sensor
The view inside the control box, you can see the resistor used for the sensor
A close up view of the LED wiring. I connected the LED resistors straight to the LEDs using a shrink wire
A close up view of the LED wiring. I connected the LED resistors straight to the LEDs using a shrink wire

The resistor I used for this sensor was a 26k resistor. This was the highest resistance I had and so I had to work with it. Using the 26k resistor dropped the values on the serial enough for me to be able to work with effectively. For example, with the 26k resistor, the “at rest” value was between 800 and 840. Although that’s a little high pressure,   tattooing does require some pressure and so I decided to make the “green” up to 889, and between 890 and 909 is for “yellow” and above 910 is for “red”.

After testing the sensor with a tattoo machine, some fine-tuning had to be done, but more or less the response through the LEDs was sufficient for me.  

Code

To build this sensor tool, I decided to work based off one of the example codes provided in the Arduino software. However, the original code only included 1 LED with different functionality than what I’m looking for, so, some changes had to be done to the code.

First, I added adjusted the code to remove the outputValue because I did not need the values to be mapped to 255, instead, I used the original 0-1023 range and split it into three levels, 0-840 for acceptable pressure and added an “if statement” to let the green LED value “HIGH” when the statement is true. Then, I added an “else if” statement for the yellow and red values 840-910, then 910 and above respectively. This way, the relevant LED lights when the relevant pressure value is reached.

Full code here

Started from an Arduino example code, and changed to fit this tool's functionality
Started from an Arduino example code, and changed to fit this tool’s functionality

Insights

Building this tool was a special experience. I remember using the tattoo practice sheets and thinking that they were not very effective and I remember wanting to do something about it. This experiment gave this chance and I am glad that I came out of it knowing more than going in.

Learning the different uses for the conductive sheets was a helpful exercise, this is my first real exploration into the conductive fabric world, but I can already see how much value it can add to our lives. However, I also learned that they are not easy to work with and troubleshooting can be also difficult since there are no parts to fix. For example, the values I received on the serial port did not match the values I got when I was filling out the sheet at the beginning. So, I had to revisit those values and see why they are different and how I can try to fix them. Eventually, I was able to map the values I received

I also learned how important resistors are when using conductive fabric with Arduino. When I was testing different resistors to see how the values change, I noticed that without the correct resistor, it’s almost impossible to receive accurate or stable values.

 

Next Steps

As I mentioned before, this is an early prototype, even though it functions well enough, in my opinion still looks rough. So, for my next iteration, I would like to finalize the look and the style of the device. Moreover, I want to consider more possibilities for the materials besides wood, perhaps consider a 3D printed base that can house all the electronics, while providing support to hold the silicon and the Velostat sheets.

Also, I want to purchase a full set of resistors and test out a few more options for more accurate values. If I can drop the “at rest” value using a higher resistor, it can allow me to fine-tune the sensor even more, which would eventually make the response more accurate to the pressure of the needle on the tattoo machine.

Happy Hat

During the ideation process in class, I got 8 suggestions from the pile and out of the eight suggestions, the one that stood out for me was “Happy Hat Skiing”. The reason why I liked this idea was that I enjoyed picturing a happy ski hat, especially when it combines knitting and sewing with technology to get some interesting results. This approach of combining past and future skills and techniques is a personally interesting field for exploration.

My initial sketch of what I envisioned the hat to look like. It shows a hat with LED that lights using a battery.
My initial sketch of what I envisioned the hat to look like. It shows a hat with LED that lights using a battery.

 

Documentation

In the beginning, my idea was to create a hat that predicts the wearer’s mood and reflects it through an LED in the “fluff” at the top of hat. However, I am personally not sold on the idea of technology with mood prediction because of the social impacts it would have. So, eventually, I decided to go with a knitted and sewed hat with LED light in the fluff ball and ON/OFF functions rather than mood prediction.

Knitting was very challenging at the beginning and my first 6 or so attempts failed. However, after repeating a few times, I started to understand knitting and it can be used. I considered the option of knitting the conductive thread through with the yarn, but I wasn’t sure where I wanted to place the thread yet and so I decided to sew the conductive thread in the texture once I’m done knitting. I started with two 20-knot batches of knitted textile, not perfect, but enough to create a rough prototype of the hat by sewing the two batches together with normal thread.

Started with a 20 knot black knitted yarn. I still face issues at the first and last knot of each row
Started with a 20 knot black knitted yarn. I still face issues at the first and last knot of each row
Started with a 20 knot black knitted yarn. I still face issues at the first and last knot of each row
Started with a 20 knot black knitted yarn. I still face issues at the first and last knot of each row

 

I also knitted a 20 knot red yarn for the top part of the hat.
I also knitted a 20 knot red yarn for the top part of the hat.

Then I sewed a conductive thread from the LEDs to the positive and negative lines of the tester, which is sewed to the edge of the hat. When the circuit is closed, it lights the LEDs, which are 2 generic yellow LEDs connected using conductive thread to the battery.

Testing the circuit before closing the loop of the hat
Testing the circuit before closing the loop of the hat
When the circuit is close, 2 LEDs light up, which looks pretty funny on a hat.
When the circuit is close, 2 LEDs light up, which looks pretty funny on a hat.

Insights

I still find challenging to work with textiles since it is a new exploration for me and is still hard for me to visualize, especially in the ideation stage. However, this experiment pushed me to explore my prototype through and learn more about knitting. I would also like to explore different types of techniques and material for knitting because I believe knitting can be a surprisingly useful solution depending on how it is used.

Since I did not have the right frame for the circular weaving, I was able to repurpose an old frame by drilling through it and inserting yarn.
Since I did not have the right frame for the circular weaving, I was able to repurpose an old frame by drilling through it and inserting yarn.
I experimented with circular weaving also. I inserted conductive thread thoughout the lines.
I experimented with circular weaving also. I inserted conductive thread thoughout the lines.

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Next Steps

For the next step, I would like to find a better way to close the circuit, perhaps using a button or a sensor to light the LED. Also, I would like to focus more on creating a better prototype of the LED fluff ball because it can be used on its own, added to any hat, to light up through a button or an app in the future. An interesting approach to that would be to explore using felting to create fluff ball that lights under a certain temperature or with rain.

If done nicely, the fluff ball can be a nice addition to any ski or winter hat.