DEVELOPMENT OF A HARDWARE-SOFTWARE SYSTEM FOR AUTOMATED PLAYING OF A SINGING BOWL WITH REMOTE WI-FI CONTROL

Abstract

Introduction. Modern living conditions lead to increased chronic stress levels
among a significant portion of the population. As shown by Goldsby et al. [2], systematic exposure to
singing bowl sounds positively affects mood, reduces tension and improves subjective well-being.
However, traditional playing of a singing bowl requires constant human presence, which limits its use
in unattended scenarios such as falling asleep or solo meditation. The development of an automated
system capable of playing the bowl independently while allowing remote control is therefore a
relevant engineering task at the intersection of IoT systems and wellness technology.
Purpose. The purpose of this work is to develop and practically implement a hardware-software
system for automated playing of a singing bowl with remote Wi-Fi control, and to investigate the
effectiveness of the selected hardware and software solutions.
Results. The system is built on the NodeMCU ESP8266 development board, selected through
comparative analysis against the Arduino Mega 2560 + ESP8266 configuration. NodeMCU's native
RTOS enables concurrent asynchronous HTTP server operation and GPIO actuator control; its builtin SPIFFS file system hosts SPA web interface assets; and its single-board architecture simplifies
development and deployment. The electromagnetic actuator, switched through an F5305S MOSFET
module with optical isolation, implements strike strength control through temporal encoding:
activation pulse duration (150–350 ms) determines strike strength, compensating for the inability to
perform analog current control via NodeMCU GPIO. Three operating modes are implemented:
Manual (single strike on demand, strength proportional to button hold duration), UnpredictaBell
(pseudo-random autonomous playing within user-defined strength and interval ranges), and
DreamDive (gradual fade-out followed by fade-in timed to a user-specified alarm, suitable for sleep
and wake scenarios). Since NodeMCU has no access to astronomical time without Internet
connectivity, the DreamDive mode receives timing parameters as millisecond deltas calculated by the
browser client from Unix Epoch. The web interface is a Single Page Application built with Preact.js (a
3 KB lightweight React alternative) and communicates with the device via a REST API on
ESPAsyncWebServer. Configuration persistence uses JSON files in SPIFFS flash memory, providing
over 30 million write cycles. Functional testing confirmed correct operation across all modes, stable
Wi-Fi in both AP and STA modes, concurrent multi-client support without instability, and DreamDive
timing accuracy of ±1–2 seconds over a 15-minute period.
Conclusion. A fully functional hardware-software system for automated singing bowl playing
with remote Wi-Fi control has been developed and validated. The scientific contributions are: (1) a
temporal encoding method for electromagnetic actuator force as an alternative to PWM under GPIO
analog output constraints; (2) the DreamDive algorithm with a linear fade profile tied to astronomical
time via browser-side delta computation; (3) an RTOS-based IoT architecture resolving the
concurrency conflict between network stack and actuator control tasks. Future work includes acoustic
feedback via a microphone sensor, machine-learning-based rhythm pattern generation, WebSocketbased real-time state synchronization, and migration to the ESP32 platform for greater resources.