racheln – F15 60-223: Intro to Physical Computing

Fabric Sensor: Soft Sensor

Thu, 03 Dec 2015 15:59:14 +0000

(link to our past documentation of this project)

(code for this project can be found here)

We designed a fabric sensor intended for the user to take one-word notes and send said notes as reminders to themselves.

Our primary purpose in creating this sensor was to write reminders on a device without the rigidity found in most devices offering the same service.

What our project actually ended up being was an exploration in soft wearables and sensing.
We discovered that the reason soft wearables are not the first choice of many is because the margin for error is so much smaller when dealing with dynamic material.

We also discovered several key aspects of creating soft touch pads. Most importantly is the overall construction. To sense position, we used three layers of material:

conductive fabric (grounded)
a spacing mesh
a piece of velostat (with 4 connections to measure resistance)

By pressing on the fabric, a connection is made between the conductive fabric and a point on the velostat. The resistance from each measurement point to the point of contact is then measured with an ADC.

We experimented with several conductive fabrics, spacing meshes, and connection orientations. Our process can be found in our previous documentation (linked above).

Also, the xy data from the sensor needs to be linearized. The linearization method depends on the orientation of the connections, but for our final prototype we linearized using the catenery curve (http://forum.arduino.cc/index.php?topic=184285.0).

plan for information flow with the sensor

hypothetical layout of the sensor

rudimentary visual prototype

visual prototype in use

sewing conductive fabric to make the buttons

sewing wires attached to conductive fabric buttons

sewing the arm straps on and defining the sensing area

inner velostat hand-sewn (because we were afraid that the sewing machine would rip through the velostat given its thickness), wires at four corners with copper tape on ends,

light blue bean, with wires soldered to it to connect it to the ADS 1015 Breakout to give us four analog breakout pins instead of two, which are how many are available on the light blue bean

testing the sensor with visual output in Processing

circuit diagram of our ADS 1015 Breakout to light blue bean

YouTube / Rachel N – via Iframely

getting the light blue bean’s accelerometer data

YouTube / Rachel N – via Iframely

testing in progress

Final project:

in off mode; no LED on

on, as indicated by red LED. ready to write.

simple controls to decide when we start, end, and give ourselves reminders

light blue bean circuitry and wires hidden under fabric flap!

YouTube / Rachel N – via Iframely

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Fabric Sensor Prototype

Thu, 19 Nov 2015 14:47:32 +0000

By Rachel Nakamura (rnakamur) and Joseph Paetz (rpaetz)

We wanted to create a soft, fabric sensor that one could interact with to create reminders for later if one doesn’t have paper, pens, notebooks, or ways to record reminders immediately available.

The idea of creating something more wearable and natural than a smartwatch is what first appealed to us. We did a lot of experimentation with various materials, various mesh spacing fabrics, arrangements of connectors, and in particular, our calibration algorithms.

YouTube / Rachel N – via Iframely

We also played around with Light Blue Bean and got it to talk to a Macbook, but getting an Android phone to control it is another problem entirely.

For further, more detailed documentation of our working process for the past few weeks can be found here:

Google Docs – via Iframely

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One-in-one-out: “A Sensory So-Long”

Wed, 30 Sep 2015 04:08:08 +0000

Teaching children to say goodbye is frequent topic of discussion in parenting literature. One Harvard Medical School Professor, Susan Linn, says that, “[kids should know that] although no one can stop transitions, everyone has a chance to discover what you can do to contribute to the experience, to acknowledge, mark and take ownership of saying goodbye”. But really, what do we know about what children think about when they say goodbye? What would “taking ownership” of saying goodbye mean to them? When we first created our piece we wanted to provide an answer to this question. With the presentation of our piece, whether that’s the drawings, the handwriting, or even the children singing the songs, we wanted to convey how children use different senses as coping mechanisms to make saying goodbye a little easier. Though, once people started to interact with it they created their own meaning for it by making their own songs from the notes or even attempting to play the song backward. We realized that our experiences only highlighted how little adults understand about how children part ways. Children are all about the what; to them, the why and how really don’t matter. Our piece, “A Sensory So Long” (SSL), has become a commentary on how little is understood about how children part ways.

The main function of SSL lies within the two half circles of conductive tubing surrounding the octagonal case. The tubing has a linear resistance, which allows the user to create different resistances by grounding the tube at different locations. The Arduino reads the resistance and calculates the position of the ring along the tube. The Arduino then sends the position to a Macbook hidden under the case over a serial connection, using the Firmata firmware. The info is then interpreted using a Pure Data patch that maps the Arudino input to different points in the song. This allows the user to scrub forward and backward through the song.

All the technical specifications can be found here:

http://time.com/3902181/how-to-help-your-kids-say-goodbye/

YouTube / Rachel N – via Iframely

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Sensing Prototype: Collabright

Tue, 22 Sep 2015 03:26:13 +0000

Ninety percent of communication is nonverbal. Though everyday life is full of nonverbal communication such as traffic signals, morning alarms, and even facial expressions, people often find themselves unable to work as a team once they can no longer verbally speak to one other.

So our group posed the question, what if we forced two people to work together by communicating through outputs appealing to two different senses?

Collabright bridges two users by allowing one to control sound output in the form of the classic “Happy Birthday” and the other to control visual output in the form of a strip of LED lights. The user whose output is sound controls the song by running a piece of wire down a length of rubber tubing at varying speeds and positions while the user who changes the LEDs controls the lights by running a piece of wire around a color wheel, also composed of rubber tubing.

The idea is that the users can create an experience together that is more powerful than when either one works alone.

http://courses.ideate.cmu.edu/physcomp/f15/60-223/wp-content/uploads/2015/09/20150921_233428.mp4

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