Monday, August 27, 2018

DAY 1 Notes 8/27/18

DAY 1 NOTES 8/27/18

2 types of current

  • Direct Current (DC) - Moves one direction
  • Alternating current (AC) - Alternates directions
Movement of electrons is a current.
All materials have resistance - friction as electrons move along.
Insulator- High resistance material (plastics, rubber, etc)
Conductors- Low resistance material (metals)

1 Amp of current - 6.25x10^18 per second
Resistance is lower in a thicker wire because theres more material to move along (ex. a wire pipe will move more water)
I(Amps)=V(Voltage)/R(Resistance) <-----Ohm's Law

Power never connects directly to ground.
There should always be a load on the circuit.

Circuit- A system that uses electricity to do some type of work.
Circuit Diagrams are also known as a Schematic.

Components - common part, manipulate current to do work.
Two common types:
  • Through hole(PHT)- older, uses legs that pass through holes
  • Surface Mount(SMT)- sit directly on the board.
Every component that is manufactured has a data sheet where you can view all the pertinent info for voltage, resistance, etc.

-a store of electrical potential
-supply DC
- come in a variety of voltages(V) and capacities known as Ampere-Hours(Ah)

-connect a section of circuit
-typical application is to connect the power
  • open- off position, not conducting
  • closed- on position, conducting
  • terms on data sheets are "normally open" (NO) and "Normally closed" (NC)
-controls currents
-common shape is a barrel with stripes denoting value of the resistor.
-measured in Ohms.
-use Omegas as symbol.
-common values/multipliers:
  • Kiloohm (thousands)
  • Megaohm (millions)
-There are apps to calculate the value of your resistor.

-common values:
  • picoFarads (trillionths)
  • nanoFarads (billionths)
  • microFarads (millionths)
-Light Emitting Diodes
-they have two polar legs:
  • Anode (positive)-longer leg, inside flag is smaller
  • Cathode (negative)-typically shorter leg, flag inside is larger
-integrated circuits
-typically two rows of legs, sometimes one row.
-kinda works like a lego brick, is a "process" that is commonly used enough to be packaged and utilized as a single component.
-each leg does a specific job, these are specified on the data sheet
-come in many different sizes.

Examples of Physical Computing projects:

  • EyeWriter
-used eye tracker to move a cursor around a field.
-made with a pair of glasses
-developed to assist a graffiti artist with ALS who could no longer move.

  • Text Rain
-people moving between a projection on the wall and a camera affect the movement of falling text on the projection.

  • Beatriz DaCosta's Pigeon Blog
-pidgeons wearing small sensors fly from a distant location to home, collecting information about air quality along the way.

  • Zap Away
-Anti-rape bra that zaps would-be assailants.

  • Mic Jammer
-emits an ultrasonic frequency that jams microphone recordings.

  • Touchy

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