Week 2 Notes

January 17th Homework Notes

Basics of Electricity

Two Types of Electricity:

AC: alternating current

• voltage goes positive and negative
• meaured in volts (V)
• cycles per second mearues in hertz (Hz)
• power out of a wall socket/outlet
  • Standard US outlet: 110V 60Hz
  • Standard UK outlet: 220V 50Hz

DC: direct current

• constant voltage
• measures votage between positive and negative
  • negative = 0V
  • positive = voltage of current
• batteries

Ohm’s Law: V = I x R (volts = current x resistance)

Power Triangle: P / I x E (power(watts) / resistance x volts)

Multimeter can meaure volts, current and resistance

How a Breadboard Works

• Allows wires to connect while avoiding soldering
• Numbered rows are connected underneath whitin ron, not between rows
  • trough in the center of board disconnects the two sides
• positive and negative colluns are conneced unerneath within the column, but not across
  • sometimes disconnected halfway down board, depending on size

Flashlight Circut

Components:

• LED light
• fixed restrictors
  • have specific ohms
• blue nob for variable resistance
  • 0-10k ohms

When connceting positive battery, always connect last to avoid short circuting the board

Schematics and Diagrams

Has various symbols for each part

Components in a Flashlight Circut

LED

• Needs to be oriented positive/negative correctly
  • inside LED bulb-
    • larger wire filament = negative
    • smaller wire filament = positive
  • on rim of LED bulb casing- flattened edge = negative
  • short leg of wire = negative
  • long leg of wire = positive

Resistor

• non polarized - does not have positive/negative ends
• gold stripe = 5% resistance
• 3 colored striped tell ohms
  • first stripe - first number
  • second stripe - second number
  • third stripe - number of zeros
  • colors -
    • black = 0
    • brown = 1
    • red = 2
    • orange = 3
    • yellow = 4
    • green = 5
    • blue = 6
    • violet = 7
    • gray = 8
    • white = 9
  • examples
    • 10k ohms= brown/black/orange
    • 10 ohms = brown/black/black
    • 330 ohms = orange/orange/brown
    • 1.5k ohms = brown/green/red

Lab 1

Too many volts can burn out a compontent

• Volts = pushing
• Amps = drawing

Lab 2

Voltage divider = resistors on group and volt end to change coltage recieved

Multimeter

• can measure
  • DC Voltage (DCV)
  • AC Voltage (ACV)
  • DC Amps (DCA)
  • Resistance
• com = minus (negative) input
• put dial at next highest number than the voltage
  • allows most accuracy

Patentiameter = variable ohms nob

Vout = Vin x (R2 / R1 + R2)

January 18th Class Notes

IDE = Intergrade Development Environment

Platform.IO - includes a library for Arduino (requires “#include " command)

Micro controller board - Arduino UNO

• microcontroller
• crystal
• power port
• varios pins
• Works on 5v
• others work on 3.3v
• most electronics work on 3.3v

GPIO = General Purpose Input and Output

Digital Vs Analog

• digital
  • either off or on, binary
  • examples
    • lamp
    • cd
    • files
    • computer
• analog
  • continuous, non-binary
  • voltage vaule is what we are looking for
  • examples
    • dimmer
    • vinyl record
    • wax cylinder
• DAC = digital to analog converter
• ADC = analog to digital converter
• PWM = pulse with modulation (form of DAC)

Input Examples

• Sound (mic)
• Light (sensor)
• Movement (sensor)
• Switch
• Temperature (sensor)

Output Examples

• Speaker
• Motoer
• LED/light
• LED Display
• Relay

.cpp extension = c++ file

void setup(){} = code run once

void loop(){} = code run repeatedly

• not based on cycles per amount of time, but the amount of time it takes to complete all lines in code

put pin input/output modes in setup

• pinMode(pin#,mode)

turn light on

• digitalWrite(pin#,value[high/low])
• delay(ms)
  • need delay in order to have light stay on or off