Conclusion and Reflection

Though it was disappointing to me that my project could not come fully together before the 31st, I know that it almost did. There is definitely a satisfaction to having learned and accomplished so much in developing it.

The program I wrote for Processing to control the light is by far the most lengthy program I have ever written. It is not eloquent and there are some inherent limitations to its variability, including the speed of the light and the base size of the pulses/steps. In retrospect, to rewrite it from scratch, I would use a much more object oriented approach. Other things about the program which I am very happy with include the aesthetic behavior and the scalability to different room sizes. A major limitation to the entire projector set up, which I was aware of (stated in my post Timeline Reassessment on April 16th) was the inevitability of the participants shadow sometimes being an obstruction. I have already begun to think of alternatives to using a projector (not necessarily a set up with two servomechanism mounted spotlights either) for a future implementation of the project. Not using fixed projection of a graphic would make my program very different, possibly not using Processing.

With these projector limitations in mind, I was very happy with how my projection in room 109 turned out. The precarious mount I rigged on top of the light panel worked great. So did the wide-angle lens assembly I strapped in front of the projector lens. Plus I now have a lot more experience with lenses (something I actually remained reasonably ignorant of in film school).

I had never soldered anything before, nor read any circuit diagrams, but now I feel a lot more confident in both of these areas. It is still inexplicable why the HRM clicks audibly. I may dissect one over the summer to find out.

One major sinkhole of time on this project had been diagnosing the signal, rediagnosing the signal, building circuits, and rebuilding circuits. If the HRM sounds clear coming over audio, it might not be clear just as a voltage, so in retrospect, I should have hooked up my BT chip and experimented with that much sooner.

The amount of assistance I needed on this project in the electronics/hardware department was much more than I thought I would need, particularly because at the outset I did not think I would need build any circuits at all. I did a lot of hands on learning in this area, but not being capable of doing it independently was frustrating and a drag on the project. A side effect has been my newfound interest in taking the mechatronics series and learning more about interactive electronics for installation pieces (that B term summer class taught by Max and Allison sounds great).

The experience of having dedicated so much of my time and energy to a single project parallels my work on film projects last year. This project organization experience helped me a lot, though I had never had to wrangle so many different aspects of a single project together.

It is nice to be able to step away from my project and to again consider it as a whole rather than as many parts. Because I could not have anyone participate with it as was intended, it can be a little hard to judge whether it would have achieved the effect I was hoping for, but regardless, I found myself considering creative alterations of it. Keeping the project concept pure and minimal, and letting the inevitable biofeedback loop (given a correct pulse step distance) give structure and direction to the experience was important to me all along. I will definitely try to make variations on the fundamental project similarly free from semantic clutter.

Not Likely

I don't think everything will come together for presenting tomorrow at 4:30. I've incorporated serial port data related code (for the HRM to control the light) into the program, but I haven't been able to test the code at all because Processing is not reading data from Arduino yet.

Test Projection

Tonight in Rm. 109 I am testing the ramshackle projector mount and lens assembly unit I made . It covers the floor, with a tolerable level of image distortion around the top. I am going to try and balance it out a little without increasing the payload. As I pour my time in Fremont into getting the circuit to work, this other aspect of my project is almost ready.

Production Phase 2

From the start of my work on Follow Your Heart!, I’ve been fortunate to have a clear idea of how I want the final system to work and the dedication to expend a lot of energy on trying to implement my vision within my time and budget limitations. Every step I take in the development of this project requires me to do research and learn new things, often from disparate fields. When one doesn’t know the terrain in between, charting a course from point A to point B is just a series of best guesses.

As such, the timeline put forth in my concept architecture is an ambitious and under-informed reflection of what I knew about my project on April 17th. I was certainly aware of this at the time of writing, but there was no way around it: I knew there were some things I had to learn before I could know what had to be done and how long it would take. Nonetheless, inaccuracies forgiven, the timeline was useful in keeping me from getting too consumed by work in any one facet of my project to the detriment of the whole.

The biggest difference between the current state of my project and my earlier expectations is also, at this point, my biggest anxiety about the project’s timely completion. I thought getting the heart signal to my program would be easier.

No.

Why is this, the core of the project— the translation of the participant’s heartbeat to the movement of the projected light—not done yet? The device that receives the analog input from the piezo microphone and transmits data wirelessly to the computer (the Arduino BT) needs to receive a clean signal. The Arduino is not an advanced enough piece of technology that it can transmit the full audio from the mic to a computer (It’s cost had me assuming otherwise). Therefore, rather than the audio being filtered in real time by the computer (in software), it must be filtered between the piezo and the Arduino (in hardware, i.e. by a circuit).

One month, 9 trips to Radioshack and many more days in Fremont later, I am still struggling to make an adequate signal emerge from the circuit and I am still determined to get it working before this coming Monday. I sincerely hope my perseverance and patience in this matter will outweigh my frustration and inexperience.

My program that will be projected, a novel written in the language Processing, is now as far as it will go without being modified to accept heartbeat data. The dimensions of the room are adjustable, as is the speed of the light’s movement, and there is new aesthetic behavior to make the light easier to track at a high pulse rate. As I noted in my post on April 16th, the participant’s body will inevitably obstruct the path of the light from the projector to the ground at some times in the experience. Time allowing, I may try and impose a few more movement rules in my program to minimize these occurrences. Realistically, writing and debugging the Arduino code, modifying my Processing program to respond to the Arduino’s feed, and writing a suitable ending for once the participant stops following the light are going to take up all the time left for coding.

Today I have a shipment scheduled that includes a first-surface mirror and another lens (a 90mm negative meniscus to be exact). I have tested a wide-angle camera lens from CARTAH in combination with a big plano-concave lens from Surplus Shed and this has widened my projection to 18ft. width at a throw distance of 9 ft., with a tolerable amount of pincushion distortion. I do not yet know exactly how I will mount the projector, DIY lens adaptor assembly, and mirror. I have thought about it a lot, but I need to test the meniscus and get into Rm. 109 to try different things out, before I know for sure. I might bring in a ladder.

Two important timeline events I have not yet accomplished, but will be forced to relocate respectively as goals for Sunday and Monday due to the time crunch:
1. Build a housing for the Arduino and it’s circuit paraphernalia.
2. Experiment with myself as the participant of a working version and use my experience to adjust the distance of each step accordingly.

This possibly being my penultimate post on Project of 202, I would like to mention that although I can appreciate the development process and will surely use the knowledge I’ve gained (and the equipment) in my future endeavors, I have especially desired to see Follow Your Heart! complete, with everyone enjoying it and hopefully arriving euphoric and exhausted at a place where they may know themselves a little differently. Having believed in it and worked on it as though to do so was an opportunity I might not have again, I’d be very disappointed if I can’t get it together in time.

Good luck to everyone in the week ahead!

Questionnaire

Though essential technical implementations that the audience is unlikely to have a directly awareness of will consume the bulk of the remaining development time for Follow Your Heart!, some feedback would be appreciated here so that I will be able to judiciously tailor some interface aspects in the coming week:

1. Private or public? Should the participant’s space be closed to the gaze and judgment of spectators while interacting with Follow Your Heart!? I believe limiting the space of experience just to the single participant and their light/heart-avatar will lessen the participant’s inhibitions, increase their willingness to relate to their biofeedback as though it were a separate entity, and make the dark room into an introverted psychological space conducive to self-reflection. If I exhibited outdoors at night, this privacy would not be possible. To maintain a position within the social chasm that separates DDR from labyrinth meditation, would this be okay for my project?

2. Unpredictable or premeditated? Thus far, I have designed my light movement grid for quasi-random isometric motion: each pulse-step either in-line with or 60 degrees to the left or right of the previous step, with equally distributed weighting (1 in 3 chance). There is special behavior around the perimeter to confine the movement area. It has been my hope in working with this design in the limited space available to me, I can maximize the illusion of a space without boundaries (thereby minimizing the participant’s consciousness of anything but the light and it’s movement), and keep the participant on their toes, while not disorienting them. But what about setting an obviously predetermined path? What might be the benefits to using some sort of labyrinthine coil or phases of motion behavior (e.g. zig zags followed by figure eights followed by a cardioid track…)? Consider discrete motion as well: what if the light played keep-away, pulsing in one spot at a room corner, then jumping directly to another corner once the participant nears it?

3. Motivation. To make the participant follow the light, I just plan to provide explicit and simple direction via the project title and possibly a large sign exterior to the room that pictorially equates a heart shape to a circle of light. While I don’t see any fault with delivering unambiguous instruction in three words— “follow the light”— I’m also aware that doing so frames Follow Your Heart! as a kinetic game (also, being outfitted with the polar chest strap before entering a dark room is reminiscent of, say, laser tag). Any thoughts or suggestions about whether providing instructions would detract artistically from my project?

4. Initiation and Termination. How should I start the participant's following the light without it being too abrupt? I feel like I should somehow “introduce” the light to the participant before I have them follow it, but how? The end will be triggered when the participant’s heart rate plateaus/decreases (and possibly this in combination with a near-zero accelerometer reading): I would like the light to return to the participant and orbit them while they catch their breath and reflect, then it could guide them back to the exit. Are there any suggestions for an alternate ending? Would something else be more effective?

Thanks for taking the time to read though these! I look forward to your responses.

Two Weeks Left

Location:
I've got the OK from CSS to use Rm. 109 or 116 for Follow Your Heart! during 202's normal meeting time on the 29th. However, I can't confirm my use of either room yet, because I still need to run through an adequate test projection.

Short throw projection:
I am now grappling with the difficulty of getting my projection to cover the floor of a room with a relatively low ceiling. I found a not-yet-series of articles on the topic at http://digitalperformance.org/?p=133, which I wish were complete. I have marginalized, though not eliminated the possibility of tiling multiple projectors, instead feeling that constructing a DIY reflective mylar mirror or an assembly of pcv and dcv lenses will be the route I go. Neilsen Enterprises in Kent will be my source if I make a mirror.

Having checked out projectors over the weekend and experimented with putting available lenses in front of the non-removable projector lens (these being a magnifying glass and a educational children's playtoy consisting of a double-concave lens mounted in a big wooden handle), I went ahead and ordered several lenses from a optical supply company. I am sure that even with high quality lenses, there will be lot of image blurring, not to mention dimming. This is not so bad. Actually, it might even enhance the aesthetic of my program. Will it get the image to the correct throw ratio though? We'll see once the lenses come.

If the lense assembly does not work, I will have to do some speedy scouting of outdoor locations on campus to project at night. This would entail mounting the projector on the side of a building and using some corrective slant anamorphosis, either simply by keystoning, or by rewriting the program to to conform to a distorted cartesian grid, and finding a place with few walkway lamps.

The News From Fremont:
The circuit I am building to get the ticking of the polar HRM to the Arduino is running into diagnostic problems. This circuit consists of two stages, both of which are still on the breadboard: the preamp, to get the voltage to adequately use the range over 0-5V and the frequency filter, to let the Arduino just listen to the frequency band close to 5.1 KHz (the frequency the HRM clicks at). Right now, when I send voltage out to an audio cable, it seems to respond fine, but when I read the signal with a multimeter, the behavior doesn't seem at all reliable. This is frustrating. I am really hoping that I can get the HRM talking to the Arduino soon so that I can move on to more coding of my program.

Full Virus Scan

Since Saturday night my body temperature has been over 100 and I've had headaches, chills, coughing, etc. This has inhibited me from readying my prototype. I would like to be writing more of my program and finding out what specific capacitors and inductors I need to make my resonant bandpass filter. Hopefully I'll make it to class tommorrow.

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.

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 16^th, 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:

Concept Architecture

Objectives:

• 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://www.wikipedia.org/

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

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.

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.

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[1] Massimiliano Peretti, 2005.

Prelude to Proposal

In the initial process of generating ideas and considering the viability of implementation for a number of distinct project concepts.