ITP Blog

Intro to Fabrication - Week 4

September 27, 2018

The fabrication assignment for week 4 was to fabricate an enclosure for an electronic device. I decided to combine this assignment with my Introduction to Physical Computing project by building an enclosure for my sumo circuit game.

Junk Inspiration

My project’s origin began where it normally does, in the junk shelf. I found two computer speakers and opened them up to see what kind of electronic device could fit into it. I couldn’t comfortably fit my Arduino in the existing speaker case, so I decided to take the speakers and use them to power a sound-influenced sumo ring.

junk

sketches

Prototypes On Prototypes

To test whether the soundwaves would be strong enough to move game pieces on the ring, I composed a quick circuit that emitted tones and stretched a latex glove over a speaker (video demo). After I had a an Arduino program and speakers that could move game pieces using sound, I used the most ubiquitous and cheapest material in the shop to build my first prototype — cardboard. This prototype would put a sumo ring frame on top of another frame holding the two speakers, allowing the soundwaves to pulse through the stage. The players then control the speakers’ tones using potentiometers.

cardboard laser

Unfortunately, my measurement skills could be improved on (reminders to self: straight-edges aren’t perfect, the laser isn’t 100% accurate, invest in digital calipers). But since there’s so much cardboard in the shop, I laser cut another frame to hold the speakers without lasered drill holes. I used a hand drill to make the speakers’ drill holes for this second attempt.

oops

manual frame

top first

side first

Once the ring’s speaker cover prototype was finished in cardboard, I had it user tested (video) by my classmate Mark. His feedback that the circular ring should be drawn onto a flat surface instead of cut into the frame to allow the game pieces to freely move beyond the boundary caused me to produce a third cardboard ring top cover prototype.

cardboard three

Following this test, I purchased a plywood sheet from Blick to build the next prototype out of a sturdier material. I then did some test laser cuts to identify the proper settings to engrave/cut the wood into the sumo ring components and drill hole sizes for the control panel.

ring test

engrave test

hole tests

Stronger Approach

Once I was comfortable with the settings and drill hole sizes I started to cut and engrave the sumo ring components. I started with the frame to hold the speakers. And because my previous inaccurate measurement experience with laser cutting the speaker’s drill holes, I went straight to hand drilling after cutting holes for the speakers.

speaker frame

speaker frame

speaker frame

I then soldered my control panel components because I knew that regardless of the enclosure’s bottom form, the control panel components would have to wire down to the Arduino and breadboard. I attempted to use a heat shrink tubing on the soldering connecting the speakers’ existing wires to new, longer wires, but realized that the tubing was too wide to properly protect the connection.

soldering

heat shrink

all components

After the speaker frame and control panel components were ready, I then started laser cutting the top sumo ring control panel frame. I laser cut pilot holes into the control panel because I still believed the laser cutter to be inaccurate after my cardboard prototype experience. This caused me to also test expanding these laser cut pilot holes on a sacrificial piece made of the same wooden material.

first wood

pilot holes

hole tests

drill press test

Drill Pressed

It didn’t go so well. Plus, Ben noted that I’ll want to have some padding between the top ring frame and the speaker frame, otherwise the ring will rest on the speakers and dampen the vibrations. But the frames were too thick for the control panel component threads to be exposed, so I had to make holes in the bottom frames that were wide enough to fit the entire component. Creating these holes cause the middle, padding panel to break, so I glued the remaining pieces to the speaker frame.

not enough depth

broken

glue

I then used the laser cutter to produce a new top ring frame — this time with laser cut control panel holes (whose sizes were tested on a test piece before) and additional engraved control panel labels (thanks Ben for that feedback).

test holes 2

Enclosing The Enclosure

The prototype at this point still lacked a bottom and sides to enclose everything. So I did a quick box prototype using cardboard.

cardboard cutting box

taped

assembled box

But building this box in wood was going to take more time and the acoustic effects of the complete enclosure, as Ben noted, remained untested. So to keep things simple, I found a plastic bin at Muji that had enough space for the circuit components, holes to snake the control panel wires through, and rigid enough to withstand the speakers’ vibrations.

final box

The last part to assemble were the game pieces. Dana gave me the idea of using cotton balls instead of the paper balls I used in previous prototypes. ITP’s soft lab had cotton ball, fluffy-like, colorful materials, so I tried different shapes to see which moved the best across the ring.

test pieces

Finally, after countless hours and one late Tuesday night in the shop, the prototype enclosure was done (video).

Future Thoughts

Some thoughts if I were to continue iterating on this project:

  • Build more prototypes in cardboard before moving on to wood — try different base shapes, ring shapes, laser cut measurements; this will help in eliciting constructive feedback earlier in the process
  • Add an additional padding layer between the speaker frame and ring — the ring is unfortunately still touching the screws holding the speakers to the frame
  • Constantly user test — it was through user testing a prototype with an unlabeled control panel that I realized how confusing the enclosure was

Adrian Bautista

NYU ITP documentation blog.
Words are my own.