Introduction: Soft-Circuit Loteria: El Nopal

About: I'm an artist and designer currently a candidate for the MFA Design + Technology program at Parsons School of Design. I make sound and tactile installations using technology and natural elements such as soil. …


Collaboration with Sarah Page


This project is part of a series of sound sculptures called Soft-Circuit Loteria. Soft-Circuit Loteria is a series of sound sculptures with each having a sound and tactile manifestation of a stanza from a poem called Loteria by Adrian Coto.

The stanza this sculpture is referring to is:

El Nopal
Let whoever reads this understand
that when the desert took me,
it left me with only a lighter
and a friend.

How it works:

As a person touches all the needles surrounding the cactus, the sound plays underneath the cactus reciting the stanza.

Step 1: Materials


- 1 box
- 1 cactus
- rocks or dirt for plants
- needles

- stranded copper
- 1 Neodymium Magnet 1.75" X 1/4" . For example this one.
- electrical tape

- adafruit wave shield
- adafruit 20w amp
- 2 9v batteris
- sound jack to connect the wave shield and amp
- wires
- 1 or 2 Mega resistor
- breadboard

Step 2: Placing the Cactus

Find a cactus that fits nicely in a box to have space for a soft-circuit speaker underneath it and a couple of lines of copper wire around it.

Step 3: Wave Shield + Capacitive Sensing


To build and set up your wave shield follow these instructions.

Important things to remember about the wave shield:
- Use a short sound file name to save your file in the sd card, for example "NOPAL.wav"
- The wave shield only plays wav files that are 22.050 kHz, 16-bitt and Mono
- Before adding new sound files to the sd card always format the card using the SDFormatter
- Before adding any sensors try your wave shield with your computer and headphones using the example code that comes with it called "daphc" to make sure it works. (NOTE: to programmed this wave shield I used Arduino 1.0.6)
- Finally, once you know it is working, you can add the adafruit 20w amp to have a higher volume.


- Follow the diagram to have the wave shield working with capactive sensing.
- Use the code in the file: ELNOPAL_CODE

Step 4: Soft-Circuit Speaker + Solder + Test


- Cut a piece of soft copper that would fit in the middle of your box. This is the material that is going to vibrate in order to hear the sound.
- Using the stranded wire, make a spiral on the soft copper and hold it together with strong electrical tape.
- Underneath the soft copper, exactly beneath the wire spiral place the magnet.
- Each side of the stranded wire will be connected to the wave shield as the speaker. (NOTE: both ends can go in either the positive or negative side of the wave shield)


- Add a couple of lines of copper tape around the soft-circuit speaker
- Solder as many needles as you would like on the copper tape. These are the needles that are going to make your sound play
- The ends of the copper tape are going to be attached to the two wires on the diagram on the previous step
- I also added a piece of fabric on top of the copper tape, to cover it more from the rocks/dirt that is going to go on top of it


- Place your cactus and rocks/dirt on top of the speaker and the rest of the copper tape and see if you can hear the sound.