Sensthethesia

Setting Up our project was a breeze. At least my parts were. Most of the fabrication I hear was time consumming. I helped out with the main parts of the fabrication on Tuesday and Wednesday. It seemed like out project demanded blood. People were burned and hands were perferated. I was afraid that I was due for a good electrocution. It took alot of man power to hold things up and fit on all the rubber. At times I kind of wish it was a floor piece so it was easier to service. Those were some long nights, but we were a pretty good team and relations never worsened. Setting up the peice was pretty easy after that. We just bolted a mounting bracket to the ceiling and Connected the piece to a chain. As far as lighting, we decided to use just one of the overhead lights. We shined the light on the floor in front of the piece in order to highlight the interactive portion of the space. Also, it cast a large shadow behind the piece, which Nick really liked. Once we had the piece mounted on Thursday, our project was pretty much done. I came in early on Friday to test it out. All seemed fine.

Unfortunately, something happened to the motor during the show. About two or three hours into the show I noticed a problem with the motor. Before the piece was running without sticking. I think after a long term of use/drying components or perhaps after a viewer held the piece in place, there was damage to the brushes in the motor. The motor’s performance then worsened until finally it died. The motor was fairly warm at that point but not really that hot. I tried letting to cool down a little bit. After I had prognosed brush damage, Nick and Ryan really shined through by calling the nearest auto zone and picked up the nearest motor in town. While they were getting the motor I stayed and explained the piece to the viewers. The whole occurance kind of went with the theme of sustaining life as I role played that the piece had “died”. After a while there was quite a crowd waiting to see this breathing organ that thier friends had told them about and hour earlier. When the motor arrived, where was a show, kind of a concantination of a surgery and a cursing automechanic as Nick, Ryan, and I tried to install a new “implant.” There were complications however and the piece suffered “nerve damage”. The sensor bus was damaged; A Metaphorical spinal chord of the piece. We hot wired the motor to run full tilt and was able to maintain a show however. (After which I became overly portective part of the piece.)
It was very interesting environment to be in an art gallery situation. It was very new to me. I remember when the first non-biased public viewer saw our piece at 6.P.M. as he utter a long “Wow” of approvoal. It was a very gratifing and rememberable moment to me. Probably something I will remember for the rest of my life.

There were also some disspleasurable moments as well — such as when a viewer decided to vandalize our project — and some awkward moments as well — such as very beautiful and very inebriated young women asking me to make her a Batgirl suit and being very….persistant…infront of her boyfriend…
In all it was very good experience and I hope to participate in something like it again.

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On Friday I went to Nick’s studio to get some of my circuitry together. My part of the project is going inside of a large moving structure so I was concerted about 1. Getting my circuity into a small enough package 2. How to mount that to the rest of the piece 3. Making the circuit fail proof and able to withstand the duress of being moved and jolted over a long period of time. I decided the mount all my modules to a piece of wood. Then using the wood as a mounting surface to the piece. Using a piece of wood also enabled me to staple, nail, drill, wire and modules down to the support structure. This enabled me to take stress off important connections.

I used my pitch program from Wednesday to test my circuit in several way. I first used it as a stress tester. I run the program. Then I shake the circuit as hard as I can. If the sound cuts out then I know something has failed, fix it, and repeat. By the time of the lab, I was able to practically throw the thing and not have a failure although my friend dropped it later and broke something, so now it has been through a unbiased test as well.

At the lab at our space, I used the pitch program to test the range and field of the sensor with audible cues. This enabled my partner and I to discuss placements and routines that we wanted for our breathing algorithm. After the lab Nick and I tested the motor out on the mechanical structure. The resistance was to great on the up stroke so Nick devised a plan to use a tendon structure to help the motor upstroke.

Saturday I conducted an experiment at Nick studio on range values with the sensor and touched up the program and circuitry so that I could get minimum functions from the motor. Once I was finished with that I did a test of the circuit with the actual piece and the motor. All went well except the range of values in the PWM module were not great enough to make a noticeable change in speed. The sensor did to it’s job though and I was able to start and stop the motor with sensor cues. With a little bit more tweaking of code, the electronic part of the piece should be done. All that will be left to do is to finalize the visual aspects of the sculpture.

Here is my current version code:

include libsrf05.txt

to Powerup
SRF05init
clearbit 1 porta-ddr ;PWM
clearbit 1 porta
clearbit 3 porta-ddr ;On/off
setbit 3 porta
clearbit 5 porta-ddr ;Hi/Low
clearbit 5 porta

loop[
setn SRF05getvalue / 250

If(n < 3) [setn 32]
Ifelse(n < 8)[setn 0]
[
If(n > 30)[setn 30]
If(n < 2) [setn 32]
]

setbit 1 porta mwait n
clearbit 1 porta mwait (32 - n)
]
end

;Max ~7850 Min ~250
;7+ huge varience/outliers
;6ft threshold= ~3700
;5ft threshold= ~3200
;4ft threshold= >2270
;3ft threshold= >1880
;2ft threshold= >1450
;1ft threshold= >1200

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I took some time in the lab Wednesday to try out the SRF05 ultra sonic sensors. After burning up one of my logo chips with a freakish battery explosion…I got the desired effect from my configuration. I took John’s advise and used one logo chip (because I only had one left.). The program I made was pretty simple. When we goto the gallery Friday I hope to test out the range and get the proper calibrations for all the circuits I have build this past week. Also I will be able to get some input from the artistic side of the group on what we want the program to do. Here is the program I made on the fly that should do at least something final Friday.
include libsrf05.txt

to Powerup
SRF05init
clearbit 1 porta-ddr
clearbit 1 porta

loop[
setn SRF05getvalue / 250
setbit 1 porta mwait n
clearbit 1 porta mwait (16 - n)
]
end
This program has really tickled my fancy. I have made some other programs that use sensors and hand movements to change a speaker’s pitch (instead of the tone in this program) to make some kinetic musical instruments. Later I hope to make an array with the musical pitch tuning and use rounding average/ a rounding tuning method to get specific pitches instead of a glissando effect.

Here is a simple version of the musical ultrasonic sensor.

include libsrf05.txt
include libmovingaverage.txt

to Powerup
SRF05init
clearbit 1 porta-ddr
clearbit 1 porta
if MAinit 8 SRF05getvalue [prs “error]

loop[
setn MAverage SRF05getvalue
setm n / 200

repeat 10
[
setbit 1 porta
clearbit 1 porta
repeat m [no-op]
]

]

end

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It has been a couple of weeks and here is what I have done for our final project.

For the past couple of weeks I have been getting parts together.

I got:

5 amp,9-12V power supply.

some 5amp+ relays

lots of transistors and mosfets

found some LM34 temperature probes

3-5 Pelteir junctions

still have John Carper’s logo chip and bread board

Ryan got a windshield wiper motor from an 80′ Fairmont

Lots or wires and heat sinks, etc.

It’s a lot of junk really but it’s only cost me 13$ plus the motor ran Ryan 25$ so far.

The idea is to get all these pieces to work in concert. In order to really explain what I have done so far I need to discuss the goal of the piece.

We want to create a hanging sculpture that will be placed in the corner. This bio-mechanical sculpture is supposed to breathe. As viewers get closer to the piece, the breath rate is to change.

Stop

This problem has been the main problem that I have been addressing this week. Ideas of temperature, lights, or sound will be a later process.

Nick and Ryan have been working on a metal frame that will be used to support the structure and a system of crankshafts/hinges to make it breathe. The windshield wiper motor is to drive this action. I have been working on this part of the project: Motor control and Sensory perception (A.K.A. project Cerebellum)

I will try to explain what I have built but I have few pictures and the piece is broken up as Nick has the motor currently to measure it to build the housing inside the piece.

1. Power:The windshield wiper motor is a DC motor and it hasn’t pull more than 5 amps so it has worked fine with the power supply I had laying in my garage. To run the logo chips I will use another “wall wart” that the dog chewed up and happened to be around 6v.

2. Motor Control: With Relays I am able to cut the main power line from the motor to shut it off. A second 2-pull relay allows me to select the high and the low setting built into the windshield wiper motor. With some 2n2222 transistors, I am able to activate the relays with 5v logic inputs (logo chips).

For variable speed I have a Pulse Width Modulation circuit in line with the motor’s power circuit. Currently I have built my PWM module exactly like Keith’s example except with a 2n2222 transistor and a IRFZ44n Power MOSFETs. I am considering trying a totem pole driver. That is where I basically replace the 10K resistor in Keith’s example and use a properly current limited PNP transistor instead. This should give me a better response curve on the MOSFET as it builds it’s channel possibly giving me better thermal stability. But as is, everything is work out as it should.

3.Sensory:Here is where I left off this weekend. I had gotten 2 SRF10’s ultrasonic sensors. Unfortunately I didn’t have the time or resources to figure them out this weekend. What we want to have a 90 degree field (because the piece is in a corner) where the viewer can approach the piece and the sensors detect presence and range and change it’s breathe rate. We are thinking of projecting 2 sensor fields from each wall face of the corner. Since I didn’t have a working sensor array I just used a logo chip and a potentiometer to change the motor speed. So…depending on what input I can get from the sensors I will have either a basic PWM loop something like this with various motor tricks, conditions and cutoffs inside:

_____________________For an analog input A0 ____________________________

include ad.lib

to Powerup
config-analog-lines 1
clearbit 1 porta-ddr
clearbit 1 porta
end

to startup
loop[
setn read-ad 0
setm n / 32
setbit 1 porta mwait m
clearbit 1 porta mwait (32 - m)
]
end
_________________________________________________

OR….

_______________For a digital binary input (write/read port) from another logochip__________

to powerup

write portb-ddr 0

write portb 0

end

to startup

loop[

setn read-ad 0

setm n / 32

setbit 7 portb mwait m

clearbit 7 portb mwait (32 - m)

]

end

_________________________________________________

So….That where I am at. Here are some pictures and a very bad drawing Of what I have done. I couldn’t get a picture of it all together so the pictures don’t make sense.

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