1. ECE 492 - Computer Engineering Design Project
Drum Anywhere
Jake Davidson, Justin Ferris, Kelvin Liang and Shivansh Singla
2017
Objective
Our goal when starting this project was to make a fun, low cost alternative way to play drums. Drum Anywhere is an innovative way to get the drumming experience without having an actual drum set.
Synthesizer
For this project we created a digital synthesizer to process our drum samples. We store drum samples on an SD card and load the samples into memory on the board. We put these drum samples through our digital signal processor when a drum hit is registered. The signal processor serves two major functions, to combine the waveforms to produce polyphonic sound and to scale the volume of the waveforms. This is achieved in real time whenever a drum is hit until the sound has finished playing. The position of each instrument is relative to one another. Below is a depiction of our current setup.
The spatial recognition board tells the audio board which sounds to play via interrupts over the GPIO bus. One board gives the other power so we only need to plug one in.
Spatial Recognition
To determine which drum you are hitting in the drum kit we use our custom spatial recognition. On each drum stick is an Inertial Measurement Unit (IMU) which has both an accelerometer and a gyroscope on it. We use these to determine the acceleration and angular velocity of the drum stick. We process this information to determine which drum is being hit. The accelerometer measures if you are moving the drum stick and how fast you are moving it so we can determine how hard the drum is being hit. The gyroscope differentiates movement between drums or cymbals depending on which angle the drum stick is moving at and for how long. Below is a sequential visual representation of four drum hits, a transition to the upper row (cymbals), three cymbal hits, a transition back down to drums, and finally four more drum hits. This is all observed via the changes in angle about the y-axis (up/down motion).
For colour ideas, University Visual Identity Guidelines can be found here: 1
Design
Drum Anywhere is a virtual drum kit. Essentially a user is able to pick up a pair of drum sticks and play as if there was a full set of drums in front of them.
Drum Anywhere consist of two major components, the synthesizer and spatial recognition. However there are several supporting components we use like the SD card interface, LCD screen, audio codec and foot pedal. All of this is implemented on two Altera DE2 boards.
Instrument Transitions With Y-axis Gyroscope
Interfacing Two Boards
We found that the Altera DE2 board did not have enough processing power to simultaneously run our spatial recognition and do the digital signal processing required. Luckily we had two of the boards! One of the boards handles the signal processing and audio output while the other handles retrieving data from sensors and the spatial recognition.
Department of Electrical & Computer Engineering