Week 4: Color Sound Pen Prototype

Physical Computing Assignment
Fabrication Assignment

What do paintings sound like? Can I create music with color? Will a photoresistor register different intensities of light when passing over a colorful surface, enough to trigger distinct notes to play? A search result revealed this might be a possibility, but I also envisioned a handheld device to activate artwork in oh so quiet museums and galleries.  This week presented the perfect opportunity to combine assignments: a musical instrument for Physical Computing and the enclosure for Fabrication. In fact, carefully considering the enclosure was crucial to the functioning of my instrument.

Initial needs included: a constant white light source shining in the same direction as the photoresistor, a way to partially enclose the photoresistor to focus the light from one direction, and a way to ensure an equal distance between the photoresistor and the colors. In my preliminary testing with my Arduino, I triggered different notes over black and green construction paper. I tried my best to keep the resistor the same distance from the paper as altering the distance to the surface impacted the resistor's input values. I also needed an elegant and secure way to mount the LEDs and photoresistor. Because I wasn't sure if this idea would actally work, I decided to prototype enclosure iterations in paper. Photoresistors can vary in their sensitivity, so I purchased extras to have on hand. And, we have an extra parameter In our PComp section with Ayo: no boxes for our enclosures! I appreciate this prompt to really consider how form and function coexist to execute an idea.

Materials & Tools
1 8 Ohm Speaker
1 100 Ohm Resistor
1 Photoresistor
1 10K Ohm Pulldown Resistor
2 White LEDs 5mm
2 220 Ohm resistors
3 Metal LED Holders 5mm
Female-to-Male Jumper Wires
Header pins (already soldered to speaker wires)
Arduino Uno
Arduino Web Editor (sketch)
4 AA Batteries
4 AA Battery Holder with Wires
Male DC Plug Adapter with Screw Terminals 5.5 x 2.1mm
Soldering Iron
4" Diameter Mailing Tube
Heavy Weight Paper
Construction Paper in Many Colors
Hobby Knife
Utlility Knife
Adobe Illustrator
Laser Cutter


More than any other project so far I relied on a steady combination of sketching, documenting, reflecting through writing, and iterating throughout the process to identify decisions to make and potential problem to solve. Checking in with Ayo early on pushed me to solidify my proposal, create materials to communicate my idea, and form a plan for my remaining amount of time. We discussed using red, blue, and green gels over photoresistors plus white LEDs or using red, blue, and green LEDs with a photoresistor to distinguish actual colors and not just changes in the intensity of light due to the presence of a color. He also mentioned this RGB light sensor from Sparkfun, which I'm game to experiment with in the future. It made sense to me to start small, though, and see if I could build this version first, especially since I wanted to design and construct the enclosure, too.

Regarding the materials and fabrication, paper and cardboard may not be my standard for final show presentation, but it is certainly an excellent way to work out my ideas quickly by hand and polish them with the laser cutter. While clunky looking, the velcro served its purpose well and gave easy access to the electronics, especially during the many rounds of testing. 

Yes this "pen" is gigantic now, but it provides a place to start and throughout the construction I considered what I would want if I were to continue to develop the idea. Certainly I would aim to scale it down and depending on the electrical components, no doubt I would have another set of issues to address concerning their housing. In addition to learning more about electronics so my projects don't almost melt (and with that, continue to improve my soldering skills), I would nix the default Arduino tone library and either search for alternatives or collaborate with musician to make our own. (I believe an ITP resident suggested I could store hand-picked sounds on an SD card.) Finally, I would attempt to get it in the hands of other people sooner than later to learn from their feedback and ideas.