Below are videos demonstrating the multiple versions of code I used in the cubes while testing.

My initial sketches, based on component sizes, showed a cube that would need to be approximately 7 cm square. I would then have enough room for an Arduino Pro board, 3-AA batteries, QT110 chip, RGB LEDs, and enough open air that the LEDs would be able to spread the light in the cube. I had a prototype cube laser cut at 1scale1 to use while figuring out component placements and PCB board sizes. Once all the pieces for inside the cube are determined, I will have 3 final cubes laser cut, with all the necessary holes for switches cut out as well.

Hightlights:

• “How to diffuse an LED” instructables article, showing how to sand the outside of an LED for better diffusion. I’m using this method because it doesn’t decrease the brightness too much while still nicely mixing the RGB LED.
• Turkish Delight boxes make a great way of organizing all the pieces I need for each cube!
• My original intent was to etch my own PCB design to speed up the cube construction process. I’m not currently familiar with the Eagle PCB design software, and it is shorribly difficult to learn, so I am opting to just use simple “swim lane” prototyping boards.

Almost all of this will go in the cube.

Proto board will be attached to top of Arduino.

Small board to capture "button press" state.

Sanding RGB LED for better color mixing.

Inside cube, with proto board, Arduino, and battery pack.

Inside cube with button in place.

Cube with all components.

Sketch for layout of components and circuits.

Collecting components for each cube.

• button double-press (hold red light on)
• button press hold + touch tap (switches rainbow color)
• button press hold + touch hold (cross fades between rainbow colors)

My initial electronics design made use of a very small code library that would allow me to sense the touch of the button. This method did not require any additional hardware and used only a small amount of code to detect the touch. (See photo above) It is a great piece of code and only requires connecting a single wire to a single digital pin on the Arduino.

However, this method did not work for the level of control that I need for my cube. My basic debugging showed that the touch is being consistently detected, but the detection cycles quickly between “touch” and “no touch”. For my cube, I need to be able to detect when a finger is touching the button for more than 1.5 seconds, an action I’m calling a “hold”. This “no hardware touch detection” would cycle between “touch” and “no touch” so quickly when my finger was “holding” on the button, that I wasn’t able to accurately interpret the “hold” action.

I instead moved towards a “hardware required touch detection”… (see video)

The button touch is now being detected by the Quantum QT110 QTouch Sensor IC (chip). Only a simple setup is required, connecting the chip to power, ground, a capacitor to filter out noise, a wire that will be touched, and one digital pin on the Arduino to receive the HIGH/LOW output signal. The good thing about using the chip, is that it does the touch processing for me and outputs a simple HIGH/LOW signal to the Arduino, and also allows me to detect the “hold” action! Integrating this chip to the electronics was almost too easy. The only custom wiring I did was to lengthen the “auto timeout” from 10 seconds to 60 seconds. I changed one wire from power to ground for one pin on the chip to achieve this.

Functionality so far:

• button press (red light on)
• tap button touch (blue light on, repeats number of taps)
• hold button touch (blue light, cycles brightness up and down)

I never thought I would hear myself say that! Thanks to my classmate, Katrina Anderson, for the perfect idea of sewing conductive thread on top of a monome.org style rubber button.

Many updates to catch up on…

I have decided on a direction for the final prototype: a small cube with a single touch-sensitive button, that abstracts the idea of a SUI, with playful and contemplative interactions. The first step, of course, is to create this cube.

My plan is to laser cut plexi for the cube, use a monome.org style rubber button, make the top of the button touch-sensitive, include some AA batteries, throw in an Arduino Pro board and maybe an RGB LED… and POW!… a “SUI Cube!”

3rd Test of making the rubber button touch sensitive… (the 1st and 2nd attempts were with variations of using a QT110 touch sensing chip or a bare wire, both of which failed)

I know of capacitive touch chips that are available, for example, at Sparkfun. But why do I need an additional chip for sensing touch, when apparently I can do the same sensing with a piece of wire connected to the arduino? See video…

Hardware setup and Arduino code available in Arduino Playground: Native Capacitive Sensors without additional Hardware

Final Prototype

Schematic Diagrams

Entire Electronics Schematic

Arduino Connections (zoom view)

Parent Multiplexers (zoom view)

Children Multiplexers/IR Phototransistors (zoom view)

Switches/Laser Transistors (zoom view)

Parts List

• Arduino Duemilinova (1)
  • #12200020 from Electrokit.se
• 4051 Multiplexer (16)
  • #73-473-70 from ELFA
• IR Phototransistor (110)
  • #75-203-15 from ELFA
• IR Laser (2)
  • 35mW 980 nm Infrared
  • 120 degree line generator
  • #A-H980-35-3 from Aixiz
• Switch (2)
  • Push Button PCB 0.8 mm black
  • #41001412 from Electrokit.se
• Transistor (2)
  • BC337-25 TO-92 NPN 45V 500mA
  • #40320009 from Electrokit.se

Code

• Arduino: TRKBRD_build_8_8.zip [6 KB]
• Serproxy (to send data from Arduino to Flash)
• Flash movie to receive TRKBRD data: TRKBRD_flash_build_5.zip [1.8 MB]
  • Be sure to adjust the Flash security settings to allow this movie to play locally on your computer.

Video Documentation

from Make Magazine:

The video mentions that the necessary supplies are available from Jameco, but they can only ship the supplies by ground, which presents us in Europe to receive it. I think ELFA in the EU has the supplies but I am still trying to find the necessary pieces.

Electrokit in Malmö has the necessary supplies:

• Developer #41000469
• Etching #41002328 or #41002488
• UV lamp from some other store
• Light-sensitive boards such as #41004123