Portable Electronic Drum-kit
The aim of this project was to create a practice and performance tool that could be transported and configured in any way that the user wanted. The goal was to provide a playable and practical system that would resemble a real drum kit as close as possible. A huge part of achieving this was eradicating the delay of signal from the pads to the speaker; this was done using a Bela Board which has a latency of less than 1 ms. A playable surface that had a certain level of rebound was also necessary, a combination of tolex and gum rubber was used to attain this requirement.
The project consists of three elements. The first being the drum pads. These pads are constructed by super gluing a 10” disc of tolex to a 10” disc of gum rubber with a piezoelectric disc sandwiched between the two layers. The tolex was chosen because of its aesthetic appearance and durability. The gum rubber was chosen as it has a certain level of rebound and elasticity, as well as being a durable material. The second element is the Bela board and the voltage divider circuit. The voltage divider is implemented to offset the piezo signal so that the entire wave can be read, so that no data is lost due to clipping. The piezo discs are then connected to the analog pins of the Bela Board via the voltage divider circuit. The third and final piece of the system is the use of Pure Data. This is the software to create the patches that process the signal and convert it from the data read via the piezo disc to a synthesised sound that is the output from a speaker.
The end result was very close to the proposed idea. The system is easily configurable. It can withstand a considerable amount of wear and tear as well as the effects of transportation. It is very responsive and can pick up multiple strikes in rapid succession, which is a feature that greatly improves the playability. An enhancement is to be developed, allowing the ability to play dynamically and thus improve the experience.