Design of an Electronic Drum Module with an Audio Playback from an SD Memory Card
Hartikainen, Pekka (2013)
2013
Sähkötekniikan koulutusohjelma
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Hyväksymispäivämäärä
2013-06-05
Julkaisun pysyvä osoite on
http://urn.fi/URN:NBN:fi:tty-201306171262
http://urn.fi/URN:NBN:fi:tty-201306171262
Tiivistelmä
Usually in electronic drum modules the used audio samples are stored in the internal memory. It would be beneficial to have external and expandable memory for the audio samples. The main focus of this thesis is to evaluate the suitability of an SD memory card for storing the audio samples in electronic drum applications. For this purpose a simple electronic drum module with SD memory card interface is designed and the per-formance of the device is tested.
The thesis is divided into four parts. In the background part, the theoretical as-pects related to electronic drum applications and the techniques used in this thesis are explained. In the design part the design of the drum module is described in detail. Specifications are listed, and the design process is described separately for hardware, software and mechanical solutions. In the prototype manufacturing part the prototype manufacturing phase is described. Used manufacturing processes are explained, and problems and changes during the prototyping phase are examined. In the results, testing procedures and results are presented individually for hardware, real-time performance and audio quality.
Based on the results obtained in this thesis, SD memory card can be used as au-dio file storage in electronic drum applications. The highest obtained read speed is 1.0MB/s with SanDisk 2GB micro SD memory card (when bus speed is 7.5MHz with 4-bit transfer mode). The more audio files need simultaneous mixing, the more processing time is consumed. With just one file playing, no mixing is needed and high sampling frequencies can easily be used. Problems occur when many files need to be mixed simultaneously. With four simultaneously playing samples, 23438Hz is the highest possible sampling frequency that can be used without audio distortion in the electronic drum module constructed in this thesis.
The thesis is divided into four parts. In the background part, the theoretical as-pects related to electronic drum applications and the techniques used in this thesis are explained. In the design part the design of the drum module is described in detail. Specifications are listed, and the design process is described separately for hardware, software and mechanical solutions. In the prototype manufacturing part the prototype manufacturing phase is described. Used manufacturing processes are explained, and problems and changes during the prototyping phase are examined. In the results, testing procedures and results are presented individually for hardware, real-time performance and audio quality.
Based on the results obtained in this thesis, SD memory card can be used as au-dio file storage in electronic drum applications. The highest obtained read speed is 1.0MB/s with SanDisk 2GB micro SD memory card (when bus speed is 7.5MHz with 4-bit transfer mode). The more audio files need simultaneous mixing, the more processing time is consumed. With just one file playing, no mixing is needed and high sampling frequencies can easily be used. Problems occur when many files need to be mixed simultaneously. With four simultaneously playing samples, 23438Hz is the highest possible sampling frequency that can be used without audio distortion in the electronic drum module constructed in this thesis.