Published September 10, 2017 © CC BY-NC-SA

Automatizing Percussion with Solenoids: "The Sound Compass"

A very simple circuit to activate four timed solenoids for automated percussion: in this case hitting resonant plastic pipes.

BeginnerFull instructions provided7,131

Things used in this project

Hardware components

Adafruit solenoid 24V

SparkFun Resistor 1k ohm

Diode 1N4004

Adafruit Transistor TIP120

Breadboard (generic)

Power Supply 24V

Arduino UNO

Software apps and online services

Arduino IDE

MIDI-to_arduin

Story

Here is a basic project used for a sound installation called "The Sound Compass". It can be adapted to any project where you need to time four solenoids. In this special case, a MIDI file was used as a score and translated into an Arduino sketch.

View of the installation "The Sound Compass" (Pictures by Christina Goldberg)

The schematics hereunder, made with Fritzing, shows how the components are connected. I used 24V solenoids mostly because that’s what was available at the store. In this version you need to power the Arduino separately, but a smarter solution can be found.

Schematics

This scheme is basically derived from this instructable.

You can easily use solenoids with a lower voltage. In that case you can choose an adequate power supply.

The code was generated (and then modified) by programming a custom software that would create MIDI files with one MIDI note each time a recording went above a certain volume threshold. Then the duration of these notes was adjusted to few ms by using a MIDI editor. The resulting MIDI file was sent through this MIDI-to-arduno processor, after having named the MIDI tracks as needed.

It doesn’t make sense to share the whole code (more than 11.000 lines), so you find the first 100 lines in the code section hereunder.

This very basic project lets you control four solenoids; in my case it was produce for a sound art installation called "The Sound Compass":

The listener sits at the middle of four pipes, which are hit by motors producing percussive patterns. Four recordings were taken with a microphone pointing at each one of the cardinal points, at different times of the day; the pipes’ length is tuned to the corresponding “keynote” of the soundscape. The rhythm is also derived from an analysis of the sound attacks in the recordings.

Made at the I-Park residency for the Site-Responsive Art Biennale, I-Park Foundation, East Haddam CT (USA) – May/June 2017

This sound art installation appears on www.alessandroperini.com

For further permissions: https://alessandroperini.com/contact/.

Code

"The Sound Compass"

void setup(){
pinMode(2, OUTPUT);
pinMode(4, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
 
doPerformance();
}
 
void loop(){
}
 
void doPerformance(){
 
delay(10);
digitalWrite(2,HIGH);
digitalWrite(4,HIGH);
digitalWrite(7,HIGH);
digitalWrite(8,HIGH);
delay(984);
digitalWrite(2,LOW);
digitalWrite(4,LOW);
digitalWrite(7,LOW);
digitalWrite(8,LOW);
delay(299);
digitalWrite(2,HIGH);
delay(740);
digitalWrite(2,LOW);
delay(485);
digitalWrite(8,HIGH);
delay(551);
digitalWrite(8,LOW);
delay(165);
digitalWrite(8,HIGH);
delay(354);
digitalWrite(8,LOW);
delay(1);
digitalWrite(8,HIGH);
delay(344);
digitalWrite(4,HIGH);
delay(103);
digitalWrite(8,LOW);
delay(24);
digitalWrite(4,LOW);
delay(283);
digitalWrite(8,HIGH);
delay(747);
digitalWrite(8,LOW);
delay(318);
digitalWrite(8,HIGH);
delay(683);
digitalWrite(8,LOW);
delay(1);
digitalWrite(8,HIGH);
delay(58);
digitalWrite(8,LOW);
delay(493);
digitalWrite(4,HIGH);
delay(32);
digitalWrite(8,HIGH);
}