Capacitive touch sensing is a type of sensing that doesn’t require much force, if any, to trigger. Any conductive material can be a capacitive touch sensor. You just need to add power, a resistor and your touch! Here’s a great video that explains the physics behind capacitive touch: https://www.youtube.com/watch?v=jco-uU5ZgEU

Why capacitive touch?

• avoids unnecessary roughness with the quilt (in an extreme example, you don’t even have to touch it if you have a strong enough resistor)
• can work with conductive fabric so the quilt itself can be the sensor
• can detect touch through any insulating material (like the LED’s silicone casing) which would allow us to conceal a sensor if needed
• each sensor only needs one wire
• relatively inexpensive (cheaper to buy conductive fabric and cut it than to buy 900 pressure sensors)
• there is an existing capacitive touch sense library for arduino

Potential Material for the capacitive sensor

• conductive fabric (knitted superlight conductive fabric is transparent to allow the LED to shine through)
• silver ink (the ink could be painted in a circle on the quilt around the LED so as not to block the light)

Things to consider with capacitive sensing

• LED must be able to shine through the quilt
• the quilt cannot be used if it is laying on a metal or static dissipative surface. The capacitive touch-sensing circuit must be insulated
• the resistor value affects the sensitivity of the touch sensor– at the low end (1 mega-ohm) the sensor will only be activated by absolute touch, and on the high end the sensor can be activated from a distance of 12 inches or more
• each sensor requires one wire which means there will be 900 wires running through the quilt. A possible solution is to 900 pieces of conductive thread that go to a central exit point on the quilt connecting to actual wires

Female DC Power adapter – 2.1mm jack to screw terminal block  – Qty: 2, Price: $4
Tighten the screws to hold the capacitor and power/ground wires in place

Adafruit NeoPixel Digital RGB LED Strip – White 30 LED – WHITE – Qty: 60, Price: $915.60
Chosen because of its flexibility and single-addressable LEDs.

4700uF 10v Electrolytic Capacitor – Qty: 1, Price: $1.95
Used in conjunction with power adapter to power up the LED strip.

5V 10A switching power supply – Qty: 2, Price: $50
One power supply will supply power for up to 10 meters. You must use a 5V DC power supply to power the neopixel strips. Higher than 6V can destroy the entire strip.

4-pin JST SM Plug + Receptacle Cable Set – Qty: 60, Price: $81
Used to string together LED strips.

Arduino Mega 2560 R3 (Atmega2560 – assembled) – Mega! – Qty: 1, Price: $45.95

To light up our quilt, we purchased strips of digitally-addressable LEDs. There are 30 LEDs per meter which puts each LED 3 cm apart from its neighbors. Our quilt will be 2 square meters in size.
To save money, instead of purchasing 60 segments of 2-meter long strips, we purchased 30 segments of 2-meter long strips and will only light every other LED in order to keep an equal number of rows and columns. In order to maintain visual symmetry, we will place each row 6 cm apart vertically (because there will be a 6 cm distance between each lit LED on a given row). This whole layout gives us 100 3×3 grids of LEDs to represent the 9 event types per year in a century.

At this point, we are forgoing the ability to represent two countries with the same event type in the same year, as we do not have enough LEDs to form triangles.
Also to save on cost of materials, we are operating the color picker directly in the source code.

If you’re having trouble visualizing this, the sketch below details the 2mx2m quilt design. It depicts the 60×60 grid with only 30 LEDs lit across, and only 30 rows populated with strips. The LEDs that will be used are highlighted in yellow, and a sample year box is circled in red.

Additionally, leaving every other row empty allows for extendability in case we purchase more LED strips in the future. Simply slide them into the empty rows, and light all LEDs instead of every other one.

An advantage of using e-textiles for the color picker is consistency of material and style across the project. It might be strange to have a soft, flexible quilt being controlled by a bulky plastic object with buttons. Incorporating soft tech throughout all components of the physical project will help users understand how the color picker works together with the quilt. Not that it’s a hard thing to understand, it’s just that the association would feel more normal with a consistent style.

A disadvantage of using e-textiles for the color picker is that choosing a color on a piece of fabric might not have satisfying user feedback. One can imagine trying to press on a color and the fabric just folds in your hand. The button-pressing experience might be less satisfactory.

This video shows an example of a soft-tech touch pad similar to what we might consider for the color picker:

They use conductive fabric touch sensors with Arduino’s CapacitiveSensor library.

Peabody is not credited with any milestone in the history of data visualization, but her work challenges us to think about how data can be presented and interpreted through image. Her visualizations used a 10×10 grid overlaid with shapes and colors to represent historical events. Pictured is Peabody’s visualization of major events in the 1500s, and a key as to how each square in the 10×10 grid is further subdivided. Each color represents a specific country.

Unlike modern day data visualizations, her images were not meant to clarify the data. Her goal was to have users create these visualizations for themselves as a way of learning history. Once complete, the chart is an abstraction of the data in an entirely different form.

In recreating Peabody’s visualization digitally, we are sharing her non-traditional approaches and allowing users to participate in the creation of charts like hers. Our digital version of the project consists of three modes: view mode, build mode, and compare mode. The view mode is a digital non-interactive version of Peabody’s charts staying faithful to the original. After familiarizing oneself with the rules that govern Peabody’s visualization, the viewer can create his or her own chart in build mode. Lastly, the compare mode juxtaposes multiple possibilities of representing the data behind the visualization. In the compare mode, Peabody’s visual representation is displayed alongside two alternate visual forms: a traditional timeline of events, and a list of the elements in the html code that represent the data.

For a third alternate form of data visualization techniques, we are bringing our digital recreation to the physical world. This will consist of a physical computing interface in the form of a quilt. The quilt will have 100 squares each subdivided into a 3×3 matrix just like the digital version. The user will select a color on a separate device and then tap the squares on the quilt to trigger an LED to light up in the selected color. The result will be the abstraction of data in quilt-form.