Physical Computing Spring 2012
Hurry Slowly
I have been feeling the gravity of mortality more strongly since turning 31 and as a result have embarked on this project – Hurry Slowly. For this project I have made a camera hat out of my “Just the facts mam.” black bike helmet. Over the course of the last two years I have focused so acutely on my studies that I have rarely made time to do anything that was not completely necessary, so for this project I have made time for the following:
- Interviewing Mom about her obsession with photo documentation
- Burying and un-burying Dad’s grave
- Visiting Grandmother at her assisted living community
- Spending a day in the park with Kate my wife
- Spending an afternoon watching Kate model heels
- Building hacking a giant basement
- Documenting the trials and tribulations of building the work itself
The collected footage ranges from sappy to surreal. The six different vignettes stand alone as documents and are displayed on small screens in the overall installation, which features the helmet cam mounted to a rotating shaft ticking off the seconds of our lives like a giant clock. Surrounding the hub of the clock are seven steel stands taking the place of the numbers that are crowned with small monitors. Each tiny screen displays edited footage of one of the seven vignettes, playing on recursive loops, indicating that there is indeed, occasionally, time for the basic and essential things. Mounted to the end of the helmet cam is a small wireless security camera streaming its data live to a rear-projected image of the space and the viewers of the work. Anybody seeing the work inadvertently participants in it, if only briefly, while the endlessly panning camera displays their image, large and in charge, for anybody’s scrutiny.
I hope that this work gives people the thought to do the things that they have been neglecting, to spend time wisely, and to experience time as it actually passes rather that the temporal paradigm we have crafted for ourselves.
Le Makerbot
I’m sure you guys have seen the Makerbot 3D printers – They use stepper motors to control a plastic extruder to sculpt physical models from 3D files (sketchup, rhino etc.) I just finished putting one together and need help troubleshooting… Everything seems to be working okay – except for two of the motor controllers aren’t lighting so i’m guessing they aren’t getting power. Can someone double check the circuit? I could pay for your time – I understand its a busy time of the year.
Makerbot Website: http://www.makerbot.com/
Build Instructions: http://wiki.makerbot.com/thingomatic-doc:thingomatic-assembly-instructions
Smoothing sensor values with code
There is a smoothing example built in to the Arduino, and a smoothing function on the Arduino site. However I made my own version which I think is simpler, faster, and easier to understand.
/* Sensor smoothing by Eric Forman [www.ericforman.com] Original version 2008, updated May 2012 Smooths sensor readings by adding only a fraction of new values. The more the new value is divided, the smaller the change, thus a smoother result As with any smoothing function, the more you smooth, the slower the response time */ int sensorPin = 0; // sensor input pin int rawVal = 0; // sensor raw value float smoothedVal = 0.0; // sensor smoothed value //float smoothedVal2 = 0.0; // add additional sensor inputs if you want float smoothStrength = 5; // amount of smoothing (default 10) void setup() { Serial.begin(9600); } void loop() { rawVal = analogRead(sensorPin); delay(10); // tiny delay to give ADC time to recover smoothedVal = smooth(rawVal, smoothedVal); // use either or both values: //Serial.print(rawVal); //Serial.print("\t"); Serial.print(int(smoothedVal)); // * int() truncates float decimal places * Serial.println(); } float smooth(int t_rawVal, float t_smoothedVal) { return t_smoothedVal + ((t_rawVal - t_smoothedVal) + 0.5) / smoothStrength; // +0.5 for rounding }
Smoothing sensor output without code
From this excellent post by user stevenh on stackexchange.
A low-pass filter will let slow changes in your signal pass, but block faster changing signals. The basic low-pass filter is this RC-filter:
VIN is the signal from the sensor. VC is the capacitor’s voltage, which you could use to go to the ADC (Analog-to-Digital Converter) of a microcontroller, for example.
The capacitor acts as a voltage reservoir, which is filled or emptied via the resistor. The higher the capacitor’s value the longer this will take. A higher resistor’s value will cause less current to flow to and from the capacitor and also will deny fast changes.
Now you may think that the higher the values, the better smoothing you get, and that’s true, but if you go too high you’ll also prevent the normal changes due to the change in distance from the sensor. And those changes are allowed.
The key to finding the right values is the cutoff frequency, that is the frequency starting from which the filter will block a signal. For the RC filter:
Say you want to allow changes of 1Hz, that means changes which take place in 1 second. Then according to the formula
If you choose a value of 1μF for the capacitor you’ll need 160kΩ for the resistor.
Additional notes: for the Sharp sensor, try 0.1μF capacitor and 15k-22k for the resistor. Ceramic capacitor is better (non-electrolytic, non-polarized).
Levitating objects in 3D space
“with zeroN, researcher jinha lee of the MIT media lab in collaboration with rehmi post of the MIT center for bits and atoms have created a miniature anti-gravity-like space, where people and computers can interact with levitating materials in a three-dimensional environment. materials can be touched and moved, left suspended in mid-air, or programmed to follow various paths. the system also records its movement, and thus can replay human interactions.
zeroN utilizes electromagnetic forces for the levitating effect. a hall sensor tracks the location of a plastic-coated, spherical electromagnetic every several milliseconds, relaying the data to a system that adjusts the electromagnetic forces from above, to attract or repel the sphere precisely to maintain its position in 3D space. the unit also makes use of infrared stereo cameras (modified from conventional webcams) and a kinect sensor to detect human presence and motion.
in addition to being used for scientific study and simulations, ‘zeroN’ can be used to program camera paths for rendered animations, or the prototyping of movements for CGI mapping. conceptualized as a sun or lamp, the sphere can be used to test lighting interactions and conditions on ground surfaces and architectural or scenographic models. the surface of the floating sphere can be used for visual projections, offering interesting possibilities for interactive planetary visualizations and artistic interventions”
http://www.designboom.com/weblog/cat/16/view/21046/mit-media-lab-zeron.html
Touché gesture sensing
Touché is a new sensing technology that proposes a novel Swept Frequency Capacitive Sensing technique that can not only detect a touch event, but simultaneously recognize complex configurations of the human hands and body during touch interaction. This allows to significantly enhances touch interaction in a broad range of applications, from enhancing conventional touchscreens to designing interaction scenarios for unique use contexts and materials. For example, in our explorations we added complex touch and gesture sensitivity not only to computing devices and everyday objects, but also to the human body and liquids. Importantly, instrumenting objects and material with touch sensitivity is easy and straightforward: a single wire is sufficient to make objects and environments touch and gesture sensitive.
We demonstrate the rich capabilities of Touché with five example setups from different application domains and conduct experimental studies that show gesture classification accuracies of 99% are achievable with our technology.
http://www.disneyresearch.com/research/projects/hci_touche_drp.htm
Affection Research Lab
Installations that respond to the “noise” your cell phone.
