The electronics and sound system for the a w a s h assemblage are built into the rear of panels 7 & 8 that exhibit the marine flora, rock and marine life depleted from the eastern coastline of Newcastle Beach over an undetermined period of time but within a documented two year time frame from early 2020 to late 2022. I wanted to add a soundtrack to the assemblage and accompany this with air and light movement to highlight and wash the captured marine life’s flora and fauna out to sea. The simple but profound soundtrack provides a countdown to the end of life as we know it living on the shores of the oceans we love to inhabit.
I trigger a diffused white 10mm LED, a small 6V DC motor and a mono 16 bit, 22,050 Khz WAV audio file. The Ultrasonic Range Finder I have used provides very short to medium range detection and is programmed in an Arduino sketch to turn everything ON when it detects an object between 15cm to 1.2m. The Range Finder can provide accurate readings of 0 to 255 inches (0 to 6.45m) in 1 inch increments with little or no dead zone.
The components shown above, along with the Arduino sketch spin the motor and turn the LED on for the duration of the WAV sound file (in this sketch for approx 60 secs) . By changing the duration of the sound file I can change the duration of the motion and light emission. On the breadboard I can switch between a 220 Ohm or a 100 Ohm resistor to alter the brightness of the LED.
The core technology for the project includes: an Arduino Uno R3, an Adafruit Wave shield for Arduino Kit (v1.1) an LV-MaxSonar -EZ1 High performance Sonar Range Finder MB1010 (with a 25v 100uF capacitor). Other components include: jumper wire, 16 GB microSDHC card & adapter, half-size breadboard, 270 Ohm resistor (red, purple, brown stripes), PN2222 Transistor, Diode 1N4001, a 25v 100uF capacitor, a 9V AC Adaptor.
I used the Arduino Lesson 13. DC Motors by Simon Monk from the Adafruit Learn website to hook up the 6V DC motor correctly. I then added the light, range finder and audio from previously adapted sketches. See: https://learn.adafruit.com/adafruit-arduino-lesson-13-dc-motors/overview
Be carful to pin correctly from the breadboard to the Wave Shield. I had some trouble getting the simple light on and off using either Digital pins in 11, 12 or 13, which I later found were used by the card reader on the Wave shield and can’t be used for anything else.
Motor GND pin to Digital i/o = 8; LED GND pin to Digital I/0 = 7; Range Finder signal pin to Analog in = 0; +5V & Gnd to +5V & Gnd of breadboard
For the audio amplification and output I have used a small Adafruit Mono 2.5W Class D Audio Amplifier – PAM8302. It’s a very small and powerful mono amplifier that can deliver up to 2.5 Watts into 4-8 ohm impedance speakers. If you want stereo sound output try using the Adafruit Stereo 3.7 (or 2.8)W Class D Audio Amplifier.
The pin configuration for the small amplifier is:
5V dc to breadboard pin +; GND to breadboard pin —; Audio in + to + on Waveshield (outer pin behind mini jack output); Audio in — to — on Waveshield (inner pin behind mini jack output). Power to the Arduino is from a wall 9V AC Adaptor, not just USB. The speaker output is connected to a small 15W 8-Ohm full range speaker. Alternatively I can connect the stereo mini jack output to a more powerful amplifier and speaker system.
All electronic and artist components are sourced in Australia from:
• Canvas prints by Stephen Neal Printing, Mount Victoria, NSW.
• Little Bird Corporation Pty Ltd https://www.littlebird.com.au/
• The mono speaker was originally sourced from Jaycar https://www.jaycar.com.au/shielded-3-inch-15w-8-ohm-full-range-speaker/p/AS3034