December 03, 2005
Pinwheels
We've been plodding through our final projects both in spatial design and physical computing. In spatial, we're working on sound domes, in pcomp we're converting breath into light. Pcomp has been a struggle with materials, building a working pinwheel that can reliably close a circuit and which doesn't degrade in quality over time. I think we're finally on to something but we are running out of time so the next couple of days are crucial. The new idea behind our project is giving the individual the ability to 'see their breath'. You blow a pinwheel and once it stops the candle begins to blow out. The blowing out is relative to how long the pinwheel is spinning.
Posted by mb2811 at 09:53 PM
October 23, 2005
Transistor
We had to figure out how to use a transistor for our breathing project. A transistor has three legs, a Base, Collector and Emitter. The base takes five volts from the PIC. If there are five volts up on the base, then the transistor powers through 12 volts (or the required power through another power source) to the component that is attached to the transistor.
The collector and emitter are hooked in together with a diode pointing in the collector direction. The white band on the diode points to the collector. The collector goes to one leg of the component.
The emitter is hooked up to the other leg of the component and ground. The other leg of the component is connected directly to power.
I hope that makes sense.
Posted by mb2811 at 08:06 PM
September 28, 2005
Week 3 Notes: Physical Computing
We spent half the class discussion our 'observation' assignment and the other half going over analog and digital output. The observation assignment is a precursor to us proposing something to augment or improve a space.
My group evaluated the ITP lounge but didn't get a chance to propose this week. We will be doing that week 4 with the second half of the assignment. We jumped the gun a little bit in the proposal stage so this extra week has given us time to go back and properly observe.
Tech Part
The capacitors that Todd added to my board are there to even out the circuit. The capacitors act as a sponge. They collect and then evenly release the electricity so that it flows at a constant rate. They compensate for any surges.
For our lab this week we are going to take analog input and output to a serial device hooked into hyperterminal. The analog in is initially going to be a pot.
I also (finally) got a copy of Physical Computing so i'm getting into that. Good stuff.
Posted by mb2811 at 03:51 AM
September 17, 2005
Week 2: Physical Computing
Multimeter: Make sure you are plugged into COM (common ground) and v/horseshoe (voltage / resistance). A straight and dotted line measures DC and a wavy line measures AC current. Always start by measuring something you know to see if the multimeter works.
Student Question: A potentiometer has three prongs while a photo resistor only has two prongs because a photo resistor only has one value when the resistor is initiated. With a pot, the outside legs are the maximum resistance. The middle leg creates a shortcut to increase or decrease the resistance. This range runs from zero to the maximum resistance of the pot. A pot doesn't need ground.
First Project, Week 1: Observation stage. This is the time to dream. Get a feeling for the physicality of a space and how it can be improved. What are people's existing activities in this space? Look for a good interaction scheme, for levels of communication. The interaction doesn't necessarily have to be complex, it is about design mastery. Remember, good design tends to be cyclical.
Switches: Switches that remember their state are toggle switches. Remember the basic building blocks. A switch is nothing more than two wires touching.
PICs: Make sure you buy DIP packages because they are the right distance to fit into breadboards. Some chips are too close together and are meant for machine soldering. The PIC has a clock. Every time it oscillates another instruction is executed.
We're putting code on the chip. Here's a simple routine:
main:
HIGH portb.7
PAUSE 500
LOW portb.7
PAUSE 500
GOTO main
Posted by mb2811 at 11:08 PM
September 16, 2005
ITP Message Board
Introduction
We are proposing display screens which will show a queue of people currently on the floor that need some sort of assistance. These people have a specific question which is preventing them from completing or proceeding with a task. This 'help application' should facilitate physical interactivity. It's important that a person be present on the floor to submit a question (no email via SMS unless we use GPS to verify proximity).
Help Queue
A person adds themselves to the help queue. The system collects their location (main floor, physical computing, etc.), their problem category and the details of their question. As it stands the queue is prioritized by time, it's LIFO (last in, first out). There will be a limit on the queue size. Once the max queue size is hit, any new additions to the queue will bump the last in person off of the list. We might add the ability to then mail the student's question to the itp-students mailing list.
The application is built to facilitate immediate interaction. If a question stagnates in the queue for an hour it is no longer relevant. The individual needed the answer 'now' to get their work done. An hour later is no longer 'now'. For that reason, individuals will be removed from the help queue if they are not helped within a predefined period of time (e.g. ten minutes). This help system will also have to be sensitive to different use traffic volumes.
Physical Device
It's important that the interface to this helper application is a custom physical device and is not confused with an all purpose terminal. It should only contain the functions necessary for the helper application to run. Possible components include a card swipe, buttons which singularly correlate to the functions of the application (add, delete, help, etc.) and a simplified screen and keyboard. Touch screen may also be a possibility.
Having said that, physical device development would definitely be phase two. It would be much easier to rapidly prototype it using existing all purpose technologies.
Posted by mb2811 at 10:33 PM
September 09, 2005
Physical Computing Week 1: Notes
The course is about moving away from the screen because the screen doesn't compensate for the wide range of human physical expression. Our body can interact in many more ways than the mouse and the keyboard. The question is, why does digital technology have to be so cold?
We went around the room and talked about a satisfying tool we have used. It didn't have to come from a metal toolbox.
Analog vs. Digital
Digital is on and off while analog is a continous progression limited by a finite set of inputs and outputs. Analog can be reproduced with digital but something potentially could be lost in the transition. It's relative to the application.
Digital: Is the Cat on the Mat?
Analog: How Fat is the Cat on the Mat?
To interact with analog, we need a unit of measurement. To create a system you need input (sensors) as well as output (actuators). Sensors mean listening to the user, really listening.
Electricity
There was a basic discussion of electricity and Ohm's Law:
Voltage (V) = Current (I) * (R) Resistance.
The analogy used was a water hose. You can either increase the amount of water coming out of a hose or hold your finger over the opening to make it go farther. We are talking about the amount of water versus the water pressure. Current is the amount of water and that's what kills you.
Components
A diode (for exampled a LED) only allows energy to flow one way. That's why a LED has a long and a short leg while a resistor can go in either direction. A variable resistor is also called a potentiometer or a dimmer switch. The pins are from left to right IGO. In, Ground, Out (Information).
Posted by mb2811 at 11:14 PM