Sounds for Martin Janíček's WaterMirror in Troja (Praha, CZ)

Martin Janíček asked in October 2023 to make a device that plays the sound of water on his public sculpture in the park around the castle in Troja 7. The experiment lasted some months, extending an ESP32 with a sd-card reader, a small amplifier, bone conductor, a day/night interruptor, a voltage controller and solar panel. The coding was done in the Arduino IDE, and simply loops the soundfiles on the sd-card. The transducer is attached to the metal sculpture and produces the water sound. In the end the solar solution was skipped and a 3.7V net adapter was used instead. We liked the idea of the water volume being controlled by the amount of sunlight. The sculpture would be silent in the night, on darker days and parts of winter, but Martin preferred the audience to hear it any moment they would walk in the park.

The choice of the artist always wins of course, but I am mentioning it here as part of the experiments we did: starting with a rpi 3B, a pico and zero pi, with soundcards. But these were too power hungry still. The equipment includes:

breadboard with ESP-WROOM-32

max 98357A I2S mono amp Vin=2.5-5.5V in

HW-125 SD Card Adapter

BH1750 Light sensor

Dayton Audio BCT-3 44 x 32mm Bone Conducting Transducer

Photoswitch TDL-2025-CDS daytime

Seeed Studio LIPO rider Pro

Solar Power Manager Wave Rider

LIPO 3.7V 20000mAh

several types of solar panels