IN/OUT : Vibrations

#chris rand



The input & output of the piezo sensors were set to their maximum value for this demonstration video. The camera microphone captures both the sound of the water falling onto the umbrella and the tones emanating from the output piezo.

OBJECTIVE : an Arduino project that senses physical vibrations and produced audible tones.

INSPIRATION : personal experience listening to an umbrella act as a vibration amplifier during a rainstorm or by feeling the vibrations from audible environmental noise in NYC.

APPLICATION : 1) Similar to the computational command (c:rand),  a random generator that convert the vibration of raindrops on a surface membrane into numbers or tones. 2) Explore how an INPUT/OUTPUT sensor can be applied to tree branches to reduce limb breakage due to the buildup of wet snow- reducing damage to old growth trees and avoiding power outages.


I began by researching if piezo sensors can be used simultaneously as input and output sensors and found only written reference to guide my exploration. The difficulty is to use the Arduino board’s digital and analogue pins which are normally used when more that one sensor is present in the circuit.  In theory this is possible so I built a split-leg piezo, realized it needed a resistor to protect my board, soldiered a few other versions, and tried to write the code to map both functions. img_5337


(above) Don’t cross the circuit when adding a resistor LOL !


CODE : looks simple enough but as a beginner it took me 3 1/2 hours and help from 3 people to get everything correct. It combines two different codes; one for knock and one for tone with a map function that sets the parameters between the two. I included technical descriptions in the code below (grey text) to exhibit what I learned.


I adhered the output piezo inside of a plastic cup to increased the amplitude of the tones and protect the sensor.


(Below) Here is how it looked when the circuitry and code are functioning properly.



I would continue experimenting with the one piezo sensor to execute both functions with help from more people and more trial and error. I would also create a small scale model of how this can be applied to my second intended application;

Explore how an INPUT/OUTPUT sensor can be applied to tree branches to reduce limb breakage due to the buildup of wet snow- reducing damage to old growth trees and avoiding power outages.

This process was a difficult but rewarding investigation into understanding and writing code. As a person who learns best by tactile and experiential methods, I was shocked in awe of the varieties of sensors and circuitry available when visiting Tinkersphere store ( 304 East 5th Street, NYC 10003). I have so many more ideas now of Arduino projects to build.


Author: ChrisRand

Products of Design MFA Student at the School of Visual Arts