Touch Capacitive Wall Installation

Introduction: Touch Capacitive Wall Installation

About: i.lab for Design + Making

A couple of summers ago, I saw this groovy wall installation during a tour of SparkFun Electronics: a walled filled with iconic images in conductive paint which were all connected to a Bare Conductive Touch Board with copper tape. When touched, equally iconic sounds and quotes would play.

For my remix of SparkFun's installation, I wrote an unofficial maker education version of the IB Learner Profile, the text and 3D printable files of which can be found on my Thingiverse page. It took way longer than expected, of course.

After prototyping and working on the initial version, the location of the installation had to be changed a few times, which impacted the scale and final design and materials.

Supplies:

For the final version, here's what I worked with:

Materials:

  • Reclaimed Plywood
  • Proto-pasta Conductive PLA
  • Conductive Paint
  • 1/4" Copper Tape
  • 1/8" MDF sheet
  • 1/8" ABS sheet
  • Drywall Anchors
  • 2mm Threaded Screws
  • Threaded Inserts

Hardware:
Touch Board

Software:
CorelDraw Student Edition
Tinkercad
QuickTime
Online MP4A to MP3 converter

Machines:
Ultimaker 3
Carvey CNC
Epilog Laser Cutter

Teacher Notes

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Step 1: Step 1: Making the Touch Board

This was my first time working with conductive PLA, so as an experiment, I 3D printed a fun geometric shape I made in TurtleArt and connected it to the Touch Board to test it out.

After confirming it would work, I converted the SVGs of the images that I had designed in CorelDraw (when I initially was going to laser cut these) and imported them to Tinkercad. When an SVG is imported into Tinkercad, it can be exported as an STL file for 3D printing. (Fun fact: the reverse works as well. Objects made in Tinkercad can be exported as an SVG for laser/vinyl cutting.)

If you like to see all the designs and printer settings for the touch pads, they can be found on my Thingiverse page here. Also included is the text for the audio recordings mentioned later.

After 3D printing I superglued them onto MDF hexagons, mainly to add a bit more strength to each pad since the PLA is fairly brittle. It also provided a nice contrast to the upcycled lumber they were being attached to.

For this last bit, I just arranged the finished hexagons on the lumber so they were evenly distributed, and attached with superglue as well.

Step 2: Step 2: Installing the Board and Touch Pads

First, I attached the reclaimed board (with the 3D printed symbols) to the wall with drywall anchors and screws so it would not fall on any passers-by.

Once that was done, I placed the Touch Board on the adjacent wall and marked where the pins were located with a pencil. From these marks, I used a ruler to trace lines from these pins to the touch pads.

Copper tape can be tricky to work with (to say the least) and I spent a lot of time making sure that the lines were parallel and didn't overlap, which would cause a short circuit. After this was done, I painstakingly applied the copper tape along the lines I had drawn.

Important: Don't be like me and assume that the adhesive is conductive. Mine wasn't and I had to fix it later.

In order to mount the Touch Board to the wall, I CNC milled a small piece of ABS plastic, similar to the one at SparkFun.

Because this project would be in the hallway with lots of student traffic, I wanted as many points of contact between the board and touch as possible, so I applied strips of copper tape on the front and back of the piece. I also drilled small holes in the ABS plastic piece and installed threaded inserts in the wall.

The last step was here was attaching the Touch Board to the plastic piece and the wall and applying one last layer of copper tape from the pins to the copper tape "traces" on the wall.

Step 3: Step 3: the Sound Files

The team at Bare Conductive has several stellar tutorials on working with the Touch Board, which can be found here.

For this part, I followed this tutorial on how to replace the default MP3 files that are on the board.

I first recorded students speaking aloud the text (which can be found here) with QuickTime.

Then it was just a matter of converting them from MP4As to MP3s with a free online conversion site.

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    2 Discussions

    0
    seamster
    seamster

    6 weeks ago

    Very nice! : )