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.