Difference between revisions of "Music from the Heart -- Music Suit"
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'''Insert team picture here''' |
'''Insert team picture here''' |
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=Subsystems= |
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Although intended as a single, cohesive system that would allow the user to intuitively make music, the project was easily divided into two subsystems: drum heart rate and music tones. Below is more explanation about each subsystem. |
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==Heart rate monitor== |
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In brainstorming how to translate a heart beat into a drum beat, we decided that the least intrusive method would be the best. Attaching electrodes to the user would simplify the process of identifying a heart beat, but attaching the sensors directly to the skin would be a time-consuming and personally-invasive process. Instead, we decided a finger tip sensor would be much more comfortable and easy to use. |
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To make a finger tip sensor, we used the concepts of [http://en.wikipedia.org/wiki/Photoplethysmograph photoplethysmography]. Photoplethysmography is typically used in [http://en.wikipedia.org/wiki/Pulse_oximeter pulse oximeters] and finger-tip sensors in commercially-available devices. We originally tried to hack a heart rate monitor that we had purchased, but this proved difficult, so we decided to make our own. |
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The basic concept of photoplethysmography is that blood reflects a certain amount of IR light, and the blood density in the finger changes as the heart pumps, so the IR reflectivity of the finger changes as the heart beats. Using an IR emitter-detector pair found in the mechatronics lab ('''Insert the component name here''') followed by lots of amplification and filtering, we were able to obtain a decent signal with peaks when the user's heart beat. |
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===Signal processing=== |
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The signal coming directly out of the IR detector was very weak and noisy. To obtain just the information we desired, we ran it through the following filters and amplifiers: |
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# Passive Low pass filter - cutoff frequency = '''Insert''' |
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# Inverting amplifier - gain = '''Insert''' |
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# Active Low pass filter - cutoff frequency = '''Insert''' |
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# Bandpass filter - Frequency range = '''Insert''' |
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# Comparator - output to the PIC |
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Revision as of 18:51, 15 March 2010
Introduction
This project attempted to create a natural form of musical expression by connecting sensors to the body. Six tilt switches were attached to the wrist, ankles, and shoulders, each controlling a single pitch from the pentatonic scale. The heart beat was obtained using photoplethysmography on the user's finger, and this signal was used to strike a drum in sync with the heart beat.
Team Members
- Thomas Peterson (Computer Engineering, 2010)
- James Rein (Biomedical Engineering and Music Cognition, 2010)
- Eric West (Mechanical Engineering, 2011)
Insert team picture here
Subsystems
Although intended as a single, cohesive system that would allow the user to intuitively make music, the project was easily divided into two subsystems: drum heart rate and music tones. Below is more explanation about each subsystem.
Heart rate monitor
In brainstorming how to translate a heart beat into a drum beat, we decided that the least intrusive method would be the best. Attaching electrodes to the user would simplify the process of identifying a heart beat, but attaching the sensors directly to the skin would be a time-consuming and personally-invasive process. Instead, we decided a finger tip sensor would be much more comfortable and easy to use.
To make a finger tip sensor, we used the concepts of photoplethysmography. Photoplethysmography is typically used in pulse oximeters and finger-tip sensors in commercially-available devices. We originally tried to hack a heart rate monitor that we had purchased, but this proved difficult, so we decided to make our own.
The basic concept of photoplethysmography is that blood reflects a certain amount of IR light, and the blood density in the finger changes as the heart pumps, so the IR reflectivity of the finger changes as the heart beats. Using an IR emitter-detector pair found in the mechatronics lab (Insert the component name here) followed by lots of amplification and filtering, we were able to obtain a decent signal with peaks when the user's heart beat.
Signal processing
The signal coming directly out of the IR detector was very weak and noisy. To obtain just the information we desired, we ran it through the following filters and amplifiers:
- Passive Low pass filter - cutoff frequency = Insert
- Inverting amplifier - gain = Insert
- Active Low pass filter - cutoff frequency = Insert
- Bandpass filter - Frequency range = Insert
- Comparator - output to the PIC
