Monday, April 30, 2007
Full Virus Scan
Sunday, April 22, 2007
Breakdown
Last night my laptop unexpectedly announced its retirement. It gave me a generous two hours notice to clean my stuff out and say goodbye. I plan to delay replacement until June, when I can get a better view of my computing needs and options and when time spent acquiring and breaking in a new system will not take time away from my project development.
The ramifications of this event with respect to my progress on Follow Your Heart! will be the following:
1. All my data is backed up; I will use my zen xtra as a external HDD to shuttle large project files.
2. I'll be spending much more time at school on the lab and library computers.
3. I will be inconvenienced.
Saturday, April 21, 2007
Breakthrough!
Having listened to my heart signal by pressing the piezo contact mic up to my chest, I heard a clean signal whenever I was motionless, but it became substantially noisier whenever I ran in place. Attempts to filter this noise out and isolate the pulse (with high and low pass filters, an FFT filter and an equalizer) were not achieving much. Even when it was taped over my heart and held fast by the chest strap, the large vibrations of my feet impacting the ground and the shuffling of the unit against my body were too loud and the sound of my heart beating was spread across the same frequencies.
About ready to conclude that I would have to give up on the piezo mic and instead perform surgery on my polar chest strap with an exacto-knife to try and find a place where I could solder on wires to interface it with the forthcoming Arduino chip, I suddenly heard a metronome-like chirping sound.
I had moved the contact mic from directly over my heart to the middle of my breast bone; it was now touching the center of the polar transmitter. I held my breath and the click rate subsided, then I lifted one of the rubberized electrodes off of my skin and the clicking stopped. To my immense surprise, the polar T31 was giving off an audible signal to the piezo mic!
What a relief! I could now use the polar chest strap I’d bought off of craigslist as it was meant to be used and I could also use the piezo mic I’d made, which would be much easier to figure out how connect to the Arduino.
The chirp the T31 makes every time my heart beats occupies a much narrower and more distinctive frequency distribution than the direct sound of my heartbeat, so filtering the signal became a much simpler task.
Here is the recording of the piezo mic pressed on the T31 transmitter as I stand, run in place, then stop:
Here is the spectrum analysis of that recording, showing a high spike at 5100 Hz:
I equalize the audio over this same range:
This is the well-filtered result:
The spectrum analysis of the equalized signal:
Updates on other progress:
Location: Having not yet received a reply to the email I sent on Wednesday to the departmental administrator of the Physics Astronomy building, I have not yet been able to scout the planetarium to see if it would be an appropriate space, although I am very attracted by the idea of it and have thought about a modification of my floor plan for a circular room. Here is a preliminary test sketch:
I scouted Raitt 116 and 121 last week and they would both be practical options, albeit not particularly desirable ones. 116 is an 18’ X 26’ rectangle with a 10’ ceiling, 4 windows on one wall a tile floor and all movable furniture. 121 is larger, at 35’ X 26’, with an 11’ ceiling, a wider wall of windows. Its floor is stepped and carpeted. Honestly, I am undecided about whether this additional obstacle could add to Follow Your Heart!, but I think it would more likely detract. There is a larger size projector already in 121 however, and I would need to see if I could angle it from the booth it sits in, toward a mirror on the ceiling.
Microelectronics: Having placed my order on the 16th, the Arduino BT will hopefully be arriving early next week. I purchased an accelerometer from Sparkfun today, so it may arrive a little after the Arduino. As described in my concept architecture, I plan to use heart rate as my primary system for triggering phase two of the light’s behavior. However, should I prove capable of using the accelerometer as a reliable means of locating the participant’s position relative to the light, I will use the change of heart rate just as supplemental data for the program.
Programming: Having downloaded Processing on Thursday night, I have begun to work from its examples and tutorials to write my program. Here is a screenshot of something I made Friday morning which has the isometric lattice structure I plan to use:
Tuesday, April 17, 2007
Concept Architecture
- Continue to look for ways to reduce production demands in order to meet the deadline for presentation, while preserving the heart of the project.
- Reserve a suitable site for the installation and schedule an earlier presentation date.
- Determine the wireless heart rate monitoring technology most viable for this project and find a way for a computer to receive the signal.
- Write a program that defines the ‘behavior’ of the light in relation to the space and the participant.
- Decide on the device that will shine the light and move it across the ground. Work out how this device will be mounted and controlled.
- Through experimentation, determine an appropriate unit of stride distance for the light to move per heartbeat, such that an average user will neither be pushed to over-exertion too soon, nor lose interest due to too slow of an initial pace.
- Determine a reliable method of sensing when the subject is no longer following the light to trigger the phase two of the system’s behavior.
- Provide explicit encouragement for the participant to follow the light, while still allowing some latitude for the participant to interact with the installation on their own terms.
Influences:
Amigdalae: An ‘observed artwork’ wherein the subject’s biometric correlate to emotional reaction modulates the soundtrack in real-time to the video they watch. In Peretti’s view, the resultant biofeedback loop is indicative of how our responses our controlled, rather than free.
Shadow tag: This informal children’s game revolves around recognition of an ‘other self’ projected on the ground which becomes the active agent of the player throughout the game. The avatar is defined by shadow here rather than light.
Dance Dance Revolution: An arcade game with a floor-surface interface in which one follows a choreographed pattern of illuminated steps at an increasing pace. Notably, the game tries to encourage an emotional involvement on par with the physical participation.
Labyrinths: A static outline for multidirectional movement across the ground within a constricted area, believed to assist in bringing the participant to a more focused, spiritual state of being. Despite external appearances of going nowhere, following the zigzagging path helps the user forget about their location, whereby they can concentrate on linear movement through successive moments of intensified presence.
Therapeutic biofeedback: In modern times, biometric technology meditates physiological self-awareness in order to assist the subject in increasing conscious control of otherwise autonomic processes. Throughout history, various world religions have practiced the cultivation of self-awareness and control of the body and mind (e.g. Yoga and Zen Buddhism).
Cardio-fitness programs: Guided fitness routines, the hosts of which typically exude exaggeratedly positive attitudes, presumably to mitigate the pain of the participant. In a equally disingenuous manner, during exercise in general, ones own biomomentum can leave one feel emotionally manipulated, simultaneously aching and euphoric due to endorphin rushes.
Technical Foundations:
Physical computing, programming and real-time audio processing will all be important in transforming the raw heart signal into a control mechanism of the light movement. Wiring, Arduino, and Processing are all related languages which I may be utilizing as the base for the coding.
A basic aspect of the light movement will be motion conforming to a isometric grid, always moving straight or 60 degrees relative to the last direction (so as not to disorient the participant), with special behavior at the room edges.
I have considered researched three methods for the monitoring the heart signal:
1. Electronic stethoscopy/ piezoelectricity:
I plan to build a contact microphone out of a piezo disk, connect this to the Arduino chip, and affix this new unit to the Polar chest strap.
2. Electrocardiography and VLF band radio transmission by wireless HRM:
Although I am certain that I will not be constructing a receiver for any VLF band data, interfacing the Arduino BT chip directly will the Polar T31 electrocardiograph strap will function as a back up plan in case the contact mic signal is too noisy to adequately filter.
3. Finger photoplethysmography/ pulse oximetry:
This option for my project is now obsolete. However, I would be likely to pursue this method in a full implementation of Follow Your Heart!
In order to make the projection cover as large an area as possible, I intend to mount a reflector at about 45 degrees some distance away from the horizontal projector, thus achieving greater linear distance between the projector and the floor/screen.
Sensing when the subject has subject has ceased to follow the light is important for moving the system into phase two, wherein the light will return to circle the subject and then lead them out of the room. I have considered three ways in which this may be accomplished:
1. Heart rate drop: This method assumes that the subject has stopped following the light once their heart rate wanes, thus it requires no additional equipment. However, there is no direct physical monitoring of the subject, therefore a false positive or a delayed reaction is most likely in this method.
2. Accelerometer: A chip attached to the Arduino board could measure the subject’s movement then compare this to the rate at which the light is moving. I am uncertain that this method would in any way account for direction however, so in theory a participant could keep the system in phase one without following the light.
3. Infrared detection: Thermal motion tracking could certainly ascertain the subject’s position in the room. However, such a system may be beyond the scope of this preliminary version of Follow Your Heart!
Equipment:
Project installation area: $0
Polar T31 transmitter and wrist receiver (used): $20
Arduino Bluetooth platform: $155
Piezo buzzer package: <$10
Projector: $0
Large mirror and mounting material: $50
Accelerometer : $30
Opaque sheet material for windows: $5
Estimated project cost: $270
Timeline:
4/16 Purchase Arduino BT.
4/18 Acquire buzzer package.
4/20 Consult at mechatronics lab for interfacing Arduino BT with contact microphone.
4/21 Begin writing pseudocode for light behavior.
4/23 Arduino is likely to have arrived; arrange time to interface unit.
4/26 Convert pseudocode into appropriate programming language.
5/1 Have developed a housing for Chip and a comfortable way of attachment to strap.
5/3 Integrate and refine different modules of Processing code.
5/8 Arrange to test projection’s fit to exhibition floor.
5/14 Adjust movement-unit distance per heartbeat to best fit experiment results.
5/17 Refine aesthetic of projected light visuals.
5/22 to 5/29 Ahead of schedule presentation date.
Bibliography:
http://cogimage.dsi.cnrs.fr/seminaires/resume_amygdalae_2005.htm
http://www.emant.com/index.php?tid=694006
http://en.wikibooks.org/wiki/Electronics/VLF-reception_with_the_PC
http://www.processing.org/reference/index.html
Monday, April 16, 2007
Timeline Reassessment
Follow Your Heart! is hereby officially downscaled to preliminary version status for its presentation by the end of May due to my concern that I will not be able to implement all the desired features of the full project by that time.
Major differences anticipated between the presentation version of this project and a design for a full version fall into three categories:
- Light source: Rather than using two pan-tilt servomechanism-mounted spotlights at opposite ends of the space, I will likely be taking up Max’s helpful suggestion of using a fixed projector. This is an aesthetic compromise, as I suspect that contrast between the light and dark areas will decrease. This method is also likely to significantly limit the space of movement and does not address the problem of the participant’s body obstructing the light as the two-spotlight design would. Two projector units may be necessary to adequately cover the floor of the display area.
- Heart monitoring technique: Two of the three options I am simultaneously pursuing at this stage would be attached to the participant by chest strap. Ideally, I would like to use the less invasive option, consisting of a finger clip/wrap and wristband unit. I am unlikely to address this concern in my preliminary version of my project.
- Programmed movement and installation space: While a projector is in some ways a more visually flexible system, is likely to constrain the overall size of the movement area and will necessitate different programming of the light’s movement behavior than a full version of Follow Your Heart! in order to maximize the illusion that the participant is moving in a space without boundaries. Adjusting the ideal scale of my project to available spaces is another limitation of this preliminary version.
Despite these changes necessary for meeting the presentation deadline, I am confident that the preliminary version of Follow Your Heart! will still follow through on the artistic ambitions laid out in my project proposal.
Tuesday, April 10, 2007
Proposal
Follow Your Heart!
There sometimes exists a tension between our involuntary biological processes and conscious control of our body. So to, sometimes our rational mind feels estranged from our emotions and subconscious drives. When we feel a visceral awareness of this tension, it is an experience of the momentum of life—what I will call biomomentum: the continued activity of our mind and body beyond conscious control.
It is because of this property that in the deceleration preceding our pause for a moment’s reflection, we may feel a strange awareness that our life has been living itself without us. I propose the creation of an art installation that will engage us with this other self in both competitive and compassionate modes of interaction, thereby enabling deeper self-perception and appreciation of our own biomomentum:
In a dark room, the participant will follow a light that moves across the ground in time to their heartbeat. As the user moves faster, so will their heart rate and so will the avatar of their heart, creating an accelerating feedback loop that inevitably concludes with the participant peaking and then not being able to keep up. When the participant has given up in exhaustion, the light will sympathetically return to orbit them in a protective circle, drawing a sense of closure.
The heart avatar’s continual movement away from the participant intensifies the sense of separation between the two selves of the participant, yet the participant may also feel it to be a playful bonding experience, as in synchronous dance. The inevitability of the increasing pace acts as a metaphor for the difficulty of following one’s (nonliteral) heart’s desire, and speaks to how the limits to highest things we can strive for are internal. The conscious mind is saddled with the weight of our body, while our heart, the manifestation of our subconscious and synonym for spirit, is free to lead us.
Follow Your Heart! extends the concept of the ‘observed artwork’ in the biofeedback-based video artwork Amigdalae[1] in that the participant is simultaneously in kinesthetic interaction with the artwork on a conscious level, in addition to generating the artwork at an involuntary level. Whereas the participant stimulus and the biofeedback-affected component are separate in Amigdalae (respectively, the visual and the audio), these constituent parts are unified into a single avatar in Follow Your Heart!
Most precedents for Follow Your Heart! seem generally outside of modern artistic practice. Children’s games such as shadow tag, the kinesthetic arcade interface of Dance Dance Revolution, spatial navigation of a labyrinth as an metaphor for meditation, therapeutic application of biofeedback, and even the guided fitness routines of cardio-fitness programs all seem to have some associable aspects to Follow Your Heart!
The perception of biomomentum in our lives may cause a frightening, disorienting sense of alienation from oneself and of loss of control over one’s life; it may be the feeling of time lost, or of being a slave to routine. Other times, our momentum feels like it’s definitely in a good direction, as when we are swept up with passion and find ourselves happily in unforeseen situations and doing things that exceed or defy our self-expectations. Follow Your Heart! aims to enable us to move toward a closer, more conscious relationship with our own involuntary and subconscious drives.
