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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 September 17, 2005 11:08 PM