Design of electronics Wind Chime 2.0

Abstract

Electronics Wind Chime 2.0 is an acoustic harmonic music instrument with electronics processes. It is able to play MIDI files and receive MIDI messages from another music instrument. It consists of 4 systems, Mini PC, controller, solenoid driver, and acoustics. The controller is connected to USB port in Mini PC. There are 4 displays in Electronics Wind Chime GUI, those are Menu display, Instrument Mode, MIDI Player Mode and Time Notifications Mode. Integration of the GUI, MIDI file extractor, and MIDI message reader, is coded in C#. The GUI eases users to select MIDI file that they want to play. MIDI files and MIDI messages have chunk structures that represented in hexadecimal. An algorithm was built to extract note message from MIDI file and MIDI message that will be sent to microcontroller. Sanford MIDI library is used to process MIDI messages from another music instrument. MIDI-to-USB converter is used to receive MIDI message from another music instrument. USB-to-Serial converter is also used to send the message to microcontroller. The process of ringing the chimes begins with serial data communicated via USART in the form of an array of char data type message received from the Processor Module. Each element of this array is mapped to the chime tubes respectively. An ATmega2560 microcontroller determines which driver channel on the Solenoid Driver Module becomes active based on the contents of the array, enabling the correct solenoid(s) to hit the paired chime. Beating the chime is done by giving power to the solenoid, with the capability of all solenoids hitting simultaneously on a single cycle of serial data reception. The maximum tolerable delay allowed between the two tones that are sounded simultaneously producing a chord, is below 30ms. The striking force of each solenoid array can be set to create a diversity of volume. It is set by varying a dedicated PWM signal.