Playing with Fabrics: The Eeonyx Strech Sensing Textile and star pad

For this workshop I played and experimented the Eeonyx stretch sensing fabric to send messages to processing and activate certain commands. I  wanted to create switch operations when the fabric was stretched out or not.

Figure 2. Setup.
Figure 2. Setup.
Figure 1. Eeonyx Stretch Sensor.
Figure 1. Eeonyx Stretch Sensor.

Originally, I was going to experiment with the Eeonyx StaTex Conductive Fibre and create a visualization of rain. When the conductive fabric was squeezed the rain would appear in the sketch. Holding something grey and soft like fibre reminded me of a rain cloud so I thought I’d try this idea. However I lacked materials and time so I went with the stretchy fabric route and would attempt the former later.

Here’s my workshop notes on a couple of the fabrics change of resistance I got to explore:

img_3464-1
Figure 3. Workshop 2 notes.
img_3465-1
Figure 4. Workshop 2 notes.

I used the AnalogOutSerial code from Arduino to get the values from the stretchy fabric. Whenever I stretched the fabric its resistance would change by one number. I wanted to translate this data to a processing sketch and change the background when the number changes.

Unfortunately this idea was much more difficult to execute then I realized. The sensor was really finicky and caused the background to flash when I stretched my sensor.

screen-shot-2019-02-15-at-10-58-29-am

https://vimeo.com/317417150

I tried this again with the touch pad sensor. The values were much more responsive when I touched it but I got the same finicky problem in Processing.

I also notice the change of resistance value would never be the same number when I closed the processing sketch.  Sometimes it would go below or jump to a high number so my if statements would not work and I would have to change the numbers.

 

Wether I had used the wrong code or was not filtering the data properly to get an on/of digital affect with analog data, I wish to explore the resistance of change with fabrics further and possibly create other scenarios and prototypes.

 

Interactive Massage Gloves

The objective of this workshop is to test resistive materials and analyze how they can be used as soft sensors.

First, we measured and recorded resistance values of all materials with a multimeter, and then measured their sensor values with voltage divider circuit and Arduino using “Analog ReadSerial” example; both at rest and when activated.

Testing

For Eeonyx StaTex Conductive Fiber and Eeonyx Stretch Sensing Textile we attached alligator clips directly to materials on both sided. For Velostat and Eonyx pressure sensing textile, we assembled contact pads with conductive tapes on either face to allow testing through pressing the resistive material.

Resistance values were read with the multimeter, and sensor analog values (0-1024) were read in the Arduino serial monitor.

img_7889 img_7893

img_7894 img_7895

Observations

  • Velostat reduces resistance when pressed or flexed. It’s pressure-sensitive and pressing it makes it highly conductive.
  • Eeonyx Pressure Sensing Fabric reduces resistance when pressed
  • Eeonyx StaTex Conductive Fiber reduces resistance when squished.
  • Eeonyx Stretch Sensing Textile reduces resistance when stretched

img_7896 img_7897

 

Create a Body-Centric Sensor Design, focusing on sensor construction and sensor calibration.

Strategy:

I worked towards designing an interactive smart massage gloves that have the ability to manipulate the ambient of the treatment room. The advantage of the interactive glove is that it gives the therapist the ability to control lighting remotely and simultaneously depending on the patient’s state while under treatment. The therapist can increase or decrease force on specific pressure points on the treated body to reflect muscle tension and therefore produce a relaxing ambient that will calm the patient. I constructed sensors for three fingers: thumb, middle finger and pinky finger. I had plans to give every finger the control of a different feature (such as light, sound, and scent), or of 3 different light locations in the room.

 

 Sensor Design Materials

  • Velostat
  • Felt material
  • Conductive fabric
  • Latex gloves
  • Conductive thread
  • Sewing thread & Needles
  • Arduino Uno and Bread board
  • 10k ohm fixed resistors
  • LED lights (blue, red, yellow)
  • Alligator clips and jumper wires

I constructed 3 pressure sensors using Velostat as it’s a force sensitive resistor.  the velostat was sandwiched between 2 layers of conductive fabric in the interior and felt in the exterior.

img_7905 img_7906

Each sensor was attached to the corresponding finger on the sanitized latex gloves using sewing thread. Then conductive threads ran down along the fingers to be connected to the microcontroller. For the experiment purposes, I attached them from outside, but ideally they should be invisible and embedded inside the glove’s fingertips.

img_7916

For the time being, I experimented with the thumb to control the intensity of one LED light.

img_7911

I realized that the sensor is very sensitive and the LED light was always on, even without poking it. So, I had to control the relation between pressure and light intensity and this was by uploading Calibration sketch to Arduino in order to be able to map the minimum sensor value to 0, and the maximum sensor value to 255. I modified the code to allow it to print the sensor values on the serial monitor to watch the changes in relation to light intensity.

screen-shot-2019-02-01-at-3-02-19-pm screen-shot-2019-02-01-at-3-02-44-pm

Click on the links below to watch videos of the experiment:

 

Insights:

From this experiment I learned a great deal with Arduino. I had lots of failures during my experiments. I went through many trials and errors with the sensor assembly, with the circuits and with the code. I learned that Velostat is highly sensitive and conductive, and it’s tricky to control. Also, using latex gloves wasn’t a great idea as they’re delicate and not durable. The process of experimenting with one sensor and one LED light can be duplicated to be tested with the other two sensors and whatever desired ambient feature to be manipulated.

Information sources:

Next Steps:

For next steps, I wish to work more on the aesthetics of the interactive gloves, that is by hiding the sensors inside the gloves and by choosing a more comfortable, durable and visually appealing material. Next I want to learn how to manipulate the lights remotely by researching wireless applications and studying the required software and hardware systems to achieve a successful end result.

 

Textile Messages


img_3343

 

Overview:

My ideation followed through with creating a form of data visualized Morse Code with a touch sensor on the index finger. Utilizing  p5 serial control and a p5.js sketch I created a visual incorporating the length and amount of pressure being output. This visualization translates into the long pauses and short blips of Morse Code. I expanded on code provided by Kate Hartman  to produce a dynamic visual interface that translates this analog technology into a digital formation. I thought it would be really interesting to incorporate textiles and digital aspects such as p5.js onto a famous analog technology.

img_3340img_3344

Strategy:

Thinking about how to construct the sensor and how to determine the best approach with the materials provided was my first step in planning out the project. I laid out all the conductive and non-conductive material we had been working with.  In class we created a chart of the fabrics provided and logged the values of resistance using the multimeter.  My plan was to do further research into understanding the multimeter, so I can test the sensors as I’m building. This gave me a much better understand the readings  to make the correct adjustments.

When reading resistance turn your dial to the ohms function on your multimeter. If the multimeter reads 1 or displays OL, it’s overloaded. You will need to try a higher mode such as 200kΩ mode or 2MΩ (megaohm) mode.

The meter will read one of three things, 0.00, 1, or the actual resistor value. Something important to remember is the decimal value always moves to the right. An example of this would be getting a reading of 0.97, meaning the resistor has a value of 970Ω, or about 1kΩ (in this instance you are in 20kΩ or 20,000 Ohm mode so you need to move the decimal three places to the right or 970 Ohms. 

My next process in planning was to search for code I thought would translate well and work with the sensor. I made a folder of resources and continued to collect further information I would need to refer to as I started to build and test.  

 

screen-shot-2019-02-06-at-12-12-42-am                          Data log using the multi meter to measure resistance.

 

Documentation:

 Step1. My first step was to start tracing out the shapes of my sensor on the Eeoynx material and foam mat.  Putting the shapes together with conductive fabric I constructed a touch button with Eeoynx material in-between.  The foam was to thick and you had to apply a lot of pressure for the sensor to operate well. I discovered that this would be excellent material to build a sensor that requires more force.  Moving onto felt fabric I restructured the design of the sensor.  While going through my tool kit there was a flexible thimble; I started to redesign my sensor to fit inside.  I used felt to overlay on both sides of the Eoynx material and sewed conductive fabric to the ends. Using the multimeter I then tested to see how the resistance varied and by watching the readings I could discern that I was able to apply a lot less force, and that my sensor was working correctly.  

Step 2.  Now that my sensor seemed to be built correctly and calibrated I needed to move it over to the bread board and attach it to my Micro Genuino controller. Because I needed to be able to use my touch sensor to indicate long and short pauses there had to be further testing with a visual indicator.  To do this I created a circuit with a single LED before moving to the P5.js sketch.  When attaching an LED to see how the electricity was flowing through the sensor I was able to see there was the right amount of pressure and conductivity. The second build was reliable enough that I could  now start focusing on the P5.js sketch

img_3338Step.3  Thinking of the sensor as a potentiometer led me to some of Kate Hartmans previous code. I modified the sketch.js file to be more pixelated and increased the incoming data rate. When initially testing the code there was a lag in the interaction between initiating the sensor and seeing it in the p5.js sketch.  Not having the instantaneous reflection in the sketch meant that I couldn’t transmit Morse Code because the pauses and blips were incorrect. After correcting the data rate p5 was more responsive and to fix the remaining issues I had to restart p5 serial control and restart my computer. After a hard restart I was able to find a new port and test. I had to change my port settings in the p5.js sketch but then after running through a second time was able to get my sketch and sensor working properly.

https://github.com/aliciablakey/fabric-sensor.git

Insights:

Working with conductive fabric, the use of the multimeter and understanding the way the current is traveling through the fabric is essential. Testing with foam, conductive tape and conductive fabric there was an important exploratory process in discovering the different sensitivities and affordances of all the materials used together. Originally I had thought of using the foam but through testing discovered that although this may not have been ideal for this particular project I would like to utilize the material in the future. This project also forced me to gain a better understanding of Ohms Law. I learned how to read the values coming from my sensor as a tool to calibrate and correct for better function.  Something that I’m really glad I did was creating that simple LED circuit in the beginning.  I found that it was really helpful in taking this step before going to code the p5.js sketch and that it probably saved me time in trying to accomplish the right level of accuracy in regards to getting steady output from my sensor, and how much I needed to adjust and what those settings looked like.

References:
https://www.adafruit.com/product/3669
https://www.sparkfun.com/products/retired/14112

Matrix: Kapton + Copper

Next Steps:

Going forward, if able to expand on this project I would like to create a casting to fit the sensor with a flexible material such as latex with a more interesting texture and colour. With the mechanics of the p5.js sketch working with the Arduino I would like to articulate on the visual and make it more dynamic; possibly incorporating colour within the morris code as an indication of mood to coincide with a message. Another addition would be to build sound functions and separate touch sensors for outputs of Morse Code.  I would like to explore other conductive fabrics further and create a specific feel for each output of the Morse Code. There would be 3 separate sensors,1 sensor for sound,  a 2nd sensor for visual and a 3rd sensor to create Morse code on a tape output you could actually touch and keep.

Stretch Sensor for Digits

Tyson Moll

The task for this week’s project was to develop a ‘body-centric’ technology that used resistive material.

Investigations:

During class, a classmate and I tested out five different resistive materials using both an analog multimeter and an Arduino programmed to receive analog voltage input with values within the range of 0-1023. In some cases we used alligator clips directly on the material, and in others we wedged the resistive material between two strips of conductive material attached to neoprene, to allow us to press into a soft material instead of, especially in the case of the plastic sheets, material without much ‘give’.

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It was interesting to compare readings with different testing methods on the materials we were provided. Sometimes we stretched the materials out, sometimes we replaced the resistors used in the arduino testing with other resistive values. The resistive values of the materials tended to reduce when in tension or compression; the closer the fibers (and particles in the case of the plastics) were to each other, the less resistance they exhibited. Similarly, voltage readings with the arduino were higher when there was less travel distance between the two clips attached to the materials.

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Table 1: Material Tests with Multimeterchart1

Table 2: Material Tests with Arduinosheet2

(Above: investigative tests of the material properties of several resistive materials)

The Device:

For this iteration, I decided to to try crochet with the help of my girlfriend. In my last exercise I learned to use some crochet techniques in order to bind two edges of knitted material together. From what I’ve heard, the process of crochet is faster than knitting with practice which appealed to me. The catch was that the process was slightly more nuanced; to create the knots, the crochet hook  must be weaved in and out of the material in more steps than the basic knit. The hook of the tool makes this process relatively painless though, and in a matter of minutes it felt as natural as the knitting process.

What resulted was a crochet cylinder roughly large enough for my thumb. I attached the stretchy resistive fabric with non-conductive thread in a manner that left the material in tension, then sewed conductive thread to the short edges of the strip, leaving two exposed strands at the bottom for the purposes of circuitry. Similar to the previous blog post, I wanted to explore handheld activation mechanisms, this time with the sensitivity of an analog input to Arduino.

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Testing:

I hooked up the device to an arduino programmed to take analog read input and feed it through the USB serial connection to the computer for display. I tried several on hand resistors to see which one would be most effective for the task; none of them were ‘amazing’, but the 4.7 ohm resistor paired with the arduino’s 5V power supply provided clear differences between the device being flexed and relaxed.

Next Steps: Further calibrate the resistance using the multimeter to get the largest sensitivity of data! And make more interesting devices.

capture

20190130_22131320190131_100138

 

Hydrator

Workshop #2 Notes
Olivia Prior

Github for the Hydrator

Context

This assignment directed us to test and get the readings from different types of conductive materials. We then took one of the materials and created a bespoke sensor that measured and calibrated to a body related action. I chose to create a sensor that measures how much water someone has consumed from their water bottle.

Testing the materials with the multimeter

For the first step of this project, I and a few classmates measured the different materials in our conductive fabric kits using a multimeter. We tried to be as clinical as possible with the materials and let the material rest naturally after it had been activated. The only material we did not do that for was the fibre because we wanted to see the contrast between the fibres being spread out versus tightly scrunched together.

Material: Velostat #1
Description: Matte plastic sheet
What activates it: Pressure (or bend)
How to connect: Secure conductive material to front & back face

Round # Value at rest Value activated Multimeter Resis. setting Observations
1 140000 ohm 126 ohm 200k (rest) – 200 (activated) This material seemed to have the resting values extremely high vs. the activated material. The sensor did not need a terrible amount of pressure to change.
2 32000 ohm 130 ohm 200k (rest) – 200 (activated)
3 35000 ohm 220 ohm 200k (rest) – 200 (activated)

 

Material: Velostat #2
Description: Shiny plastic sheet
What activates it: Pressure (or bend)
How to connect: Secure conductive material to the front & back face

Round # Value at rest Value activated Multimeter Resis. setting Observations
1 44400 ohm 120 ohm 200k (rest) – 200 (activated) Similar results as before, but this material seemed to have a lower resting value than the other Velostat. The sensor did not need a terrible amount of pressure to change to a lower resistance.
2 44800 ohm 109 ohm 200k (rest) – 200 (activated)
3 40300 ohm 102 ohm 200k (rest) – 200 (activated)

 

Material: Eeonyx Pressure Sensing Fabric
Description: Coated woven textile
What activates it: Pressure (or bend)
How to connect: Secure conductive material to the front & back face

Round # Value at rest Value activated Multimeter Resis. setting Observations
1 50000 ohm 150 ohm 200k (rest) – 200 (activated) A large range of values! Found to be a bit inconsistent with the resting values.
2 39000 ohm 72 ohm 20k (rest) – 2000 (activated)
3 33100 ohm 133 ohm 20k (rest) – 2000 (activated)

 

Material: Eeonyx Stretch Sensing Fabric
Description: Stretchy knit textile
What activates it: Stretching Fabric
How to connect: Clip power and ground to either end

Round # Value at rest Value activated Multimeter Resis. setting Observations
1 145000 ohm 53900 ohm 200k resistance Did not need to change the resistance for this material; the range seemed to be fairly consistent.
2 140000 ohm 53400 ohm 200k resistance
3 134500 ohm 50900 ohm 200k resistance

 

Material: Eeonyx StaTex Conductive Fiber
Description: Fluffy fibres, similar to cotton stuffing
What activates it: Squishing/compression
How to connect: Clip power and ground to either end

Round # Value at rest Value activated Multimeter Resis. setting Observations
1 12500 ohm 690 ohm 20k (rest) – 2000 (activated) This one was fun trying to scrunch it to as small as it could be. The range is quite large for this material as well. This material is incredibly responsive; a light touch changes the values significantly.
2 12300 ohm 450 ohm 20k (rest) – 2000 (activated)
3 13100 ohm 550 ohm 20k (rest) – 2000 (activated)

 

  1. For testing the Arduino’s we followed a similar clinical process: test the materials and let them rest naturally. Upon initial investigation, I was convinced that we had our setup incorrectly because the values upon activation were going up rather than lowering. After reflecting we realized that this made sense because the closer the sensors (especially the pressure ones) were together the closer the path is for the current.

Material: Velostat #1
Description: Matte plastic sheet
What activates it: Pressure (or bend)
How to connect: Secure conductive material to the front & back face

Round # Value at rest Value activated Resistor Value Observations
1 20 1015 4.7k Will not go higher than 1023? Even with different resistors. The value would often go down to nearly zero. Inconsistent resting values. The sensor did not need a terrible amount of pressure to change.
2 3 1015 4.7k
3 40 1013 4.7k

 

Material: Velostat #2
Description: Shiny plastic sheet
What activates it: Pressure (or bend)
How to connect: Secure conductive material to the front & back face

Round # Value at rest Value activated Resistor Value Observations
1 95 1021 10k Same as above, will not go higher than 1023? Even with different resistors.

The sensor did not need a terrible amount of pressure to change.

2 95 1022 10k
3 93 1022 10k

 

Material: Eeonyx Pressure Sensing Fabric
Description: Coated woven textile
What activates it: Pressure (or bend)
How to connect: Secure conductive material to the front & back face

Round # Value at rest Value activated Resistor Value Observations
1 50 1021 10k Will not go higher than 1023? Base rate is lower than the velostat
2 60 1022 10k
3 70 1022 10k

 

Material: Eeonyx Stretch Sensing Fabric
Description: Stretchy knit textile
What activates it: Stretching Fabric
How to connect: Clip power and ground to either end

Round # Value at rest Value activated Resistor Value Observations
1 54 118 10k The resting values were inconsistent. The values of the rest vs. activated were always about half.
2 60 122 10k
3 62 128 10k

 

Material: Eeonyx StaTex Conductive Fiber
Description: Fluffy fibres, similar to cotton stuffing
What activates it: Squishing/compression
How to connect: Clip power and ground to either end

Round # Value at rest Value activated Resistor Value Observations
1 570 980 10k A large array of values! I scrunched this one very tightly. Just over double the value?
2 588 976 10k
3 544 950 10k

Creating the Hydrator

For this assignment, I chose to measure the act of consuming water. My goal was to fabricate a sensor that was connected to a water bottle that would:

  1. Calibrate the sensor to the pressure from the water in the bottle
  2. Indicate and prompt the user that they should be drinking through the use of a timer
  3. After the user has consumed some water and the water bottle is placed back onto the table, re-calibrate the high and low values of the sensor
    • If the value is the same, the user did not drink water and do not reset the timer drinking timer
  4. Restart the timer and indicate to the user that they have consumed water.

I chose to fabricate the pressure sensor out of the matte velostat, conductive fabric, and the floor foam. I chose those materials as I wanted to create a shape that takes an even reading from the base of the water bottle. There were lots of this material to take from, so I knew that I would be able to produce the size and shape to take the reading I wanted.

My first step was to trace the base of my water bottle and cut out the shape of the sensor. The bottom of my bottle dipped in slightly at the middle, so I chose to use a “donut” shaped sensor that would only attach itself to the bottle’s points of contact with the table. I cut the conductive fabric slightly smaller and included flaps for the hardware connections to have enough surface area to attach.

Traced out cutouts from the base of my water bottle.
Traced out cutouts from the base of my water bottle.
Cut outs of the conductive fabric and velostat.
Cutouts of the conductive fabric and velostat.

My next step was to cut out the foam pieces and assemble the sensor. I cut the foam to be a bit wider than the velostat to allow for full coverage of the sensor. I was concerned that, because I was working with a device that carries water, there may be some potential for water to seep into the sensor.  

Assembling the water bottle sensor.
Assembling the water bottle sensor.

Before I fully attached the sensor together, I tested the values. To my surprise, my values were vastly different from my Arduino testing. My range was from 10-250, rather than 0-1023. This worried me at first, but I chose to continue with the development of the sensor and see what I would be able to do with the incoming data.

I attempted using different resistors to test the incoming data values. I found I had the best range using a 10k Ohm resistor. This was the same resistor that provided the best results in our initial testings.

Testing out the sensor before assembling it together with an adhesive.
Testing out the sensor before assembling it together with an adhesive.

After confirming that I was able to get a reading from my sensor, I used electrical tape to secure my sensor together.

Sensor attached together with tape, and connected to the circuit with alligator clips.
Sensor attached together with tape, and connected to the circuit with alligator clips.
Sensor secured together with electrical tape to avoid any drips of water from the bottle.
Sensor secured together with electrical tape to avoid any drips of water from the bottle.

My next steps were to attach the sensor to the water bottle and take readings with different values of water.

The water/pressure sensor beside a list of sensor readings that are taken in 100ml intervals.
The water/pressure sensor beside a list of sensor readings that are taken in 100ml intervals.
Sensor attached to the bottle.
Sensor attached to the bottle.

I found that there was not a significant range between 100ml intervals. This was an interesting challenge; I had initially planned to take readings on how much a user had sipped. The only major data differences were between 200ml intervals. I found that this was an unrealistic amount for a person to drink in one sitting each time the bottle would prompt them to drink.

Due to the data not providing a large enough range, I chose to include time as an indicator. If the bottle was “picked up” the sensor would not have any weight on it, therefore we could assume that the user would be drinking. The time the bottle was picked up would be timed to help ensure that the person was actually consuming.

I wrote out my entire process before I started coding.

The code process written out to help understand the order in which to write the code.
The coding process written out to help understand the order in which to write the code.
Fritzing diagram showing the LED and sensor connections.
Fritzing diagram showing the LED and sensor connections.

My first step was to ensure that the program would know that the bottle was being picked up to consume water. I tested this by using a strip of addressable LED lights as an actuator. If the bottle was unattended for more than 3 seconds, the LED lights would change to red. If the bottle was picked up the LED lights would change green. When the bottle was placed back down the timer would start again.

My second step was to calibrate the values of the sensor. I wanted to incorporate the ability to measure how much water was in the bottle after the bottle was picked up. For the first five seconds of the code, the sensor would calibrate.

I coded the rest of the program based off of these calibrated values. If, when prompted with a red LED light, the bottle was picked up for more than three seconds, placed down, and the sensor value was lower than the original calibrated sensor it would register that the person drank enough water. Otherwise, the LED light would stay red indicating that the water consumption quotient was not satisfied.

The functionality of this aspect was difficult to achieve. The results of recalibrating the sensor were inefficient. I attempted to pour out more water in an attempt to create a drastic difference in sensor values, but the values were still so minor in comparison. I chose to stick with the minimal viable functionality of lifting the water bottle up when prompted with the LED light and placing it back down again after three seconds as an indication that I drank enough water.

Results

Overall, I found this project challenging as the different sensors that I perceived to all be the same were actually drastically different. It was helpful, though, to figure out the intricacies of the sensor by creating a datasheet, as I had for the different millimetres. This whole process creates a relationship between you and the sensor and ultimately becomes an intimate experience. The sensor was crafted by your own hand and the sensor has its own unique data set.

In the future, I think I would choose to use a tilt sensor to indicate if the act of water is being consumed. I think that having the tilt sensor connect with two pieces of perpendicular conductive fabric would achieve that same concept, without the finicky aspect of the data set.

Even though the data set was much smaller than I had expected and less sensitive to the difference in the volume of water, I was surprised by how responsive the sensors were to light touches. When I was initially testing my readings for the water bottle, I could get a nice varying set of data by drumming my fingers along the top of the sensor. This could be applied in many different sound-based or visualization works.

Overall, the sensor I crafted allowed me to create a bespoke drinking experience: a bottle that responded through LED feedback to the frequency of intervals you were consuming water, and for the timed length you were in the act of drinking water.

Research & References 

Kobakant – Simple Fabric Pressure Sensors

Kate Hartman – Into to Textile Game Controllers

Thinking cap (workshop notes 2)

Testing materials

Figure 1: materials to be tested
Figure 1: materials to be tested

This project was to use material handed to us during class to make a sensor which is in a way related to the body. We started out by testing reading using a multimeter

Figure 1: Readings from Multimeter
Figure 2: Readings from Multimeter
Figure 1: Arduino Reading
Figure 3: Arduino Reading

I tested the sensor out with my classmates Olivia and Mazin. We realized that the materials were highly sensitive and that we did not actually have big enough resistors in terms of resistance which could be used for testing with the arduino. This testing helped with the general understanding of the project and different types of materials available for building soft sensors.

Process

Research

The assignment was to build a sensor that was “body’ centric in a way. My initial understanding was built by testing out the resistive materials. I decided to use the Velostat and Linquustat. I started by trying to understand the idea of something that was “ body centric”. My research included using a design thinking approach to the question of building a sensor.

screen-shot-2019-02-06-at-12-02-13-am

Understand

I used this opportunity to understand the assignments and ask myself some questions. As much as this exercise was the ability to understand materials, I saw it also as an opportunity to understand an explore the body.
what did I build?

Figure 6: brainstorming questions on how I use my body.
Figure 4: brainstorming questions on how I use my body.

During our class, kate had mentioned paying attention to the way we use our bodies. This got me thinking about the way I use my body in particular. Including the kind of things I wear. Which parts of the body do I apply the most pressure to?

The one of the interesting question that arose during my research was about the weather I was designing for One body or two bodies. This was a surprising insight because it showed the subtle ways that we not only interact with our own bodies but also many more bodies.

Kate has bought this really nice mat material which was basically the puzzle mats which usually  was also an interesting material itself to build a sensor.

figure 7: Sensor material
figure 5: Sensor material

I first cut out a triangle shape piece because I started out out by imaging a rough idea of building a napping pad (for the on the move nap).

figure: 9 understanding the materials
figure 6: understanding the materials

Unpack

I used this information I had collected in helping me to formulate what I wanted to build. I was going to the Eonyx Velostat material and the green mat. I decided this would be a great time to do a test with the testing sensor to make sure that the basic functionality is there to scale up to build the actual sensor.

I uploaded the serial input Output code from the examples and I got a good range of numbers for the the sensor value and output value. A good enough range helps with mapping of the sensor value to something else. In my case I had decided to use the a physical output like the LED strip. Through this process I had set myself some constraints in which I should ideate around.

I used the code from https://randomnerdtutorials.com/guide-for-ws2812b-addressable-rgb-led-strip-with-arduino/

as a guiding post to light the Fast led. This also involves downloading the fast.h library to the code.

Ideate

After I had unpacked my initial learnings, I proceeded by getting back to the drawing board to brainstorming sensor ideas.

  1. Hugger (sensor that helps with intimate contact)
  2. Thinking sensor (a sensor which helps you with thinking)
  3. napper (An on the go nap sensor)

After a bit brainstorming, using my constraints I decided to build a “Thinking sensor” . This was a finding I had collected in my initial phase of “understand”. I realised one of the ways in which I use my body is by always leaning on my hands. From this idea I wanted to do kind of a play on the idea of the thinking man.

screen-shot-2019-02-08-at-2-22-37-pm

 

Prototype

I started building out by using the same code as above and then running a test by lighting the LED strip using the test sensor.

Building the sensor

F
Figure 7: Building a sensor

After I built the sensor, due to the high ranges which were affected by the thickness of the sensor did not really help in the coding the sensor to switch the LED on and off. I would recommend using thinner materials

img_4734
Figure 8: Getting unusually high readings

 

Learnings and further iterations:

I used this opportunity to kind of have fun with the exercise. I found it interesting to try out these materials to understand the novel and surprising ways in which we use our bodies. Our bodies are using covered in soft materials, and the potential to integrate these materials into our everyday has great potential.

I would highly recommend using lighter material

Using resistors with values of over 10k.

Using material that pick up pressure well

Trying out different outputs such as sounds or even vibration motors.

 

 

Pressure Sensor Boots

Experiment by: April De Zen and Veda Adnani

This week was an intro to pressure and stretch sensors. There were 2 techniques that we covered in class, the first was clipping fabric and fibres with alligator clips and extending the textile to create resistance. The second technique was to create a ‘sandwich’ textile tool to hold resistant materials that will allow more current to flow once pressure is added.

After class, Veda and I thought it would be cool to create sensors that go into a persons shoe. Here are the steps we went through to build this prototype.

Step 1: Understanding the Materials
(Tests with Multimeter and Arduino)

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In class, we all received a bag of goodies, many pieces of fabric and fibre to show the resistance of a textile. So the testing began, we tested everything. We tested stretch fabrics, a grey cotton ball thingy and more black materials. Each material created resistance in different fashions so we began chatting about different opportunities that these affordances could be leveraged. Some materials offered quite a bit of resistance and others not so much, it was fascinating exploring the materials in this fashion.

Step 2: Sensor idea

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Next came ideation, what kind of sensor should we create. Light up shoes are fun for all ages, and we wanted to try making a pair ourselves. We chatted through the placement of the sensor, should it be under the heel or under the toes? The interaction for a sensor under your toes would be different than a sensor under your heel. We step heel/toe, and quite a bit more of pressure is pushed through the heel. Since the sensor was going into a shoe, it made the most sense to use a pressure sensor rather than the stretch sensor. Off we went…

Step 3: Assembly

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There is a process of making a pressure sensor, we need two pieces of non-conductive fabric that gives a bit of a squish feeling when pressed. Next, we needed two parts for conductive fabric, in this case, it was fabric tape. Then we need a material to go right in the middle which will act as a resistor, we used the velostat which was given to us for testing. Once all the pieces were cut out, it was time to sow it all together. We stitched the conductive fabric tape in place (since it was shifting around) and then some conductive thread was sown into the conductive fabric to extend the reach since this sensor is going into a shoe. Then we quickly sandwiched it all together and stitched up the sides making sure the velostat covered the conductive fabric completely. We didn’t want to current to skip over the resister we just created.

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Step 4: Testing in Shoe

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The sensors were now ready for testing. We quickly tested it outside of the shoe to make sure it would work. Since the main idea was to rThe sensors were now ready for testing. We quickly tested it outside of the shoe to make sure it would work. Since the main idea was to re-create a light up shoe, we went with using the e-textile tool with an LED for testing. It was fun testing this sensor out, the LED lite up as we stepped on the sensor. Once it was placed into the boot, we pulled the conductive thread through a few holes in the boot so we could connect the sensor again to the e-textile tool while we took turns walking.

Reflection and Learnings:
This was an enjoyable exercise. Now that this exercise is completed it easy to see the simplicity in what we created but it is also phenomenal that current can be altered through fabrics with a few simple tricks and understanding what each material can do for you. Besides taking Halloween costumes to a whole new level, we are both very excited to use sensors like this in upcoming projects.

 

Range of Motion Visualizer

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GitHub: https://github.com/npyalex/Knee-Stretch-Sensor

Overview

The Range of Motion Visualizer is an exploration of the capabilities of stretch-sensor conductive fabric. The Visualizer uses a stretch-sensor in a bending motion rather than a stretching one and visualizes the output as a multicoloured band. In concept, the Visualizer is imagined as being used as a rehab tool. When prescribed a limited range of motion as a part of physical therapy, a wearer would calibrate the Visualizer to their prescribed range. They would see their motion represented. Safe motion that would not harm their recovery would (at this stage, anyway) be represented by a small green bar. The bar would elongate and turn yellow as they approached the outside of their prescribed range, and turn red when they were outside it.

Process

After exploring the functionalities and properties of the fabrics we had been given in-class, I decided to work with the stretch sensor. I had worked with pressure sensors briefly in the first semester, so I preferred not to work with them, and had been knocking around the idea for a wearable that would visualize motion for a little while, inspired by the Motex Project for smart textiles. The stretch sensor was an opportunity to realize that idea.

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knee-fritz

I put together a circuit using the diagram provided in-class as an example, and ran it while looking at the Arduino Serial Port to see what kind of readings it generated.

Then I took some code from the Ubiquitous Computing class and used it as the basis for moving the sensor readings into Processing.

When that confirmed that Processing worked, I wrote some code to adjust the length of a displayed rectangle based on the sensor reading.

After a few tests I determined what felt like a good range to implement the changing colours – yellow for approaching the danger zone, and red for beyond.

Then I put together the sleeve for holding the sensor. I took an old sock and cut away the foot. I sewed a hem into the sock, then turned it inside out and sewed in the length of stretch sensor fabric with conductive thread.

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I left long lengths of conductive thread to attach alligator cables to while testing.

In testing this was uncomfortable and unwieldy. Because of the simplicity of the circuit I decided to minimize it. I used a small breadboard. I removed the extraneous wires and ran the power side of the sensor directly from the 5V pin. I set up the variable resistor directly from the A0 pin, and the resistor directly to ground.

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I removed the extra threads and sewed patches for alligator clips to attach to. I had to recalibrate the code at this time, as the sensor had begun returning lower readings. As a nice bonus, touching the two pads completed the circuit and served as a default “max” for the range-of-motion tracking function.

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I continued to explore visualization. I wanted to create a curve that mirrored the bend of the user’s arm. I used the curve() function, as well as explored using curveVertex() within the beginShape()/endShape() functions. I did get a reactive curve going, but I decided that it was not as strong a visualization as the bar.

silly-boy

Next Steps

This could easily be made wireless – perhaps with XBees? I would have to do more sewing, including a pocket for the microcontroller. I also considered exploring haptic feedback in addition to – or perhaps instead of – visual feedback. I would like to include a vibrating motor that would buzz lightly when in the yellow zone and strongly when in the red. Beyond that, I would want to create a means for quickly and simply re-calibrating the sensor on the fly, and continue working on using a curved image as a visualization.

References

https://github.com/npyalex/Ubiquitous-Connectivity-Project

https://docs.google.com/presentation/d/1xHIjrmXHmO3N-q6QnVvZ4OYTXpfT2C0L8y68Nwbwj5U/edit#slide=id.g4e5141135c_0_67

http://www.motex-research.eu/about-motex.html

Finger Dynamometer

1- Results from Voltmeter testing

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2- Results from Arduino testing (all with 1K resistor)

Velostat
Active: 1015
Passive: 900

Eonyx Pressure sensing fabric
Active: 182
Passive:1002

Eonyx Stretch sensing Fabric
Active: 650
Passive:100

Eonyx StaTex conductive fibre
Active: 1015
Passive: 650

3- Finger Dynamometer:

I generated a concept for called “finger scanner”. Despite its name, it does not scan your fingers but measure the strength of your fingers. It can be used just to measure your strength or to exercise and strengthen your fingers or just for fun or stress reduction. I thought it can be used by people with arthrosis or paralysis. I know some people with some of the genetic disorders may have low strength on the fingers and it is an issue for these kids’ motor development in order to keep up with their peers. This interactive product can help them to have better grip.  You can see the concept images below.

finger-scanner

It may also be used with a plastic case to make it easier to hold.  attachment-1-1

holding

Strategy: My strategy was to make a sensor in the middle of the ball using the resistor material, velositat. I placed the velostat between nonconductive material pieces. It is basically button and pressure sensor in the ball. It registers as you put some pressure on the ball. Because the ball is full (polyurethane) it reflects the pressure onto the sensor. It connects to Arduino and it shows the data of your pressure. Data is recorded to detect the strength by time as well.

Documentation

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I cut the nonconductive fabric considering ball’s size. They were two almost identical pieces. I cut the velostat fabric a little bit larger than two other pieces pieces in order to block any short contact of the conductor fabric.  I taped the conductor fabric on the nonconductive pieces. I stitched them with the velostat fabric in the middle nonconductive fabric pieces.

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I cut the ball in two and placed the sensor between two pieces. I added two polyurethane pieces to stop the two half pieces of the ball pressing the sensor. I glued the ball’s pieces, polyurethane pieces and sensor together. After that,  It looked like a ball again. It was ready to connect and be tested with Arduino.

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I wrote the code and uploaded the code inside the Arduino. You can see the code up, and reach the doc here. 

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 I set analogInPin to pin A0. I set the AnalogOutPin to pin 9.I worked with 5V. I set the other end to + (red) of the bread. I set the GRD to -(blue)

You can see the other settings in the images below.

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I could get data after I set the whole system.

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You can see the video to see it is working.

Insights:

It is my first time using Arduino. I need to practice it some more. I followed a tutorial to build the system for this time.

After making the sensor, I placed it inside the ball. I did not cut it into two at first in order to keep in one piece.  After activating Arduino I realized that value was not changing. I realized that the ball was making a big pressure onto the velostat already. Therefore, I cut the ball and added two pieces of polyurethane foams in order to stop the pressure done by the ball.  Then, I glued them together.

Values were not zero because of the pressure on the velostat done by covering eenoyx pieces and stitches holding these pieces together. Even after I loosened the stitches the high values did not change so much.

The highest value was 1023, and somehow I could not change the make it higher with coding in Arduino.

Information sources:   I used the tutorial “Analog serial sketch” at the link below. I find this website very useful.  http://arduinotogo.com/category/chapter-6/

Next Steps: In my concept, it is working with Bluetooth. If I want to continue this project I want to make it work with Bluetooth. I also want to use permanent components and materials for realistic look and usage.

 

Touchable Future

Part 1: Material Tests with Multimeter

1

To find consistent data, we decided to follow the same procedure for all the materials being tested. Every material’s resistance was written down as they were connected to the ohm meter. We would then activate the axes and read the new values on the ohm meter. After activation, we would allow 30 seconds to the material to revert to its original state, where we would read the next resting value and repeat the procedure until we received three readings for each material.

For the Econyx Stretch Sensing Fabric and Eeonyx StaTex Conductive Fiber, we were able to directly connect them to the ohm meter using alligator clips, whereas, for the Velostat and the Eeonyx Pressure Sensing Fabric, we had to use the Sandwich technique to read the measurements. To do that we used two pieces of fabric with Back glued Conductive fabric. After sewing the two edge of the parts together, we slipped in the material that we wanted to test and connect the conductive fabrics to the ohm meter using alligator clips. We cut the testing matorral bigger than the testing equipment so that it would prevent from any accidental short connection.

part-1

Part 2: Material Tests with Arduino

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To read the values using an Arduino, we made a voltage divider circuit, using the test materials as the second resistor in the circuit and running Arduino’s Analogue Read Example to read the measurements.

We initially used a variable resistor for the other resistor, adjusted to give us the smallest reading possible in Arduino at the resting position, but to confirm the numbers, we also ran all the materials using a 50 Ohm resistor (the average of the resistance from part 1 of the workshop) as well and observed the same range of results as the test with the variable resistor.

We followed the same testing structure as testing with a multimeter, giving 30 seconds between each run for the material to go back to its original shape.

part-2

Lesson Learnt:

  • Velostat:

The Velostat has a great range of resistance ( from 20K Ohm to 20 ) giving the broadest range of readings from the Arduino. Also due to its shape, it can be easily added to any design of any size and be used as a pressure sensor.

  • Eeonyx Pressure Sensing Fabric:

The Fabric was very similar to the Velostat, still a great range of resistance similar to the Velostat, but its unique texture makes it very special and can be used for places where it might be visible to the user.

  • Eeonyx Stretch Sensing Fabric:

This by far was the most fascinating sensor. We did test it on both of its axis, and it returned the same resistance. It stretches a lot and provides you with a functional difference in the resistance. It can be easily added to any design and be used as a stretch sensor.

  • Eeonyx StaTex Conductive Fiber:

This is a unique material because of its form. It can be easily used to fill an object up with and be used as a sensor. It has an excellent range of resistance but takes a very long time to recover after being activated. It also might never turn back to its original shape causing the resistance values to change quite a lot between different runs.

Part 3: Build Your Own Sensor

How nice would it be to be able to control your phone during the winter without having to search for your phone in your many jakcet’s pockets with your huge gloves. How nice would it be to control your phone by simply pressing on your fingertips? For my project, I wanted to use the Velostat to create small pressure sensors, attach them to a glove and create a method of fast communication through a smart glove.

here are the steps to build the sensors:

  1. Cut out 8 small circles of felt to use as cushion. If you want to make the pressure sensors softer, you can cut two different layers (16 pieces).
  2. Cut out 4 small circles of velostat, a little smaller than the felts.part-3
  3. Cut out small pieces of Iron glued conductive fabric and iron them as shown in the picture below.
  4. Use conductive threads to connect to the tabs of conductive fabric on the two felts.
  5. Put the three pieces together and sew them together.part-3-2
  6. Invert the glove and sew the sensors onto the tips of the fingers.img_20190129_214131
  7. Test the device using a multi meter to make sure it works.

final

Challenges:

It was very difficult to connect the sensors to the gloves and taking care of the wire connections. During the testing, the sensor did sometimes read out of range values because of short circuits in the wires. Another difficulty was to correctly position the sensors in the gloves so that when your hand is in the glove, the sensor would stay at their resting status.

Next Step:

The next step would be to come up with smaller sensors so that it would be easier to install them. I would also create a fix path for wires to reduce the chances of short circuits. For the final touch, I would connect the 4 sensors to a micro controller and set it up to control whatever device that you would like.