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Electronics 101

Basic Electronics Theory

Slides

Electricity is measured in terms of voltage, current and power. Another important quantity related to electricity is resistance.
    Voltage (volts) is a measure of the pressure, or FORCE, of electricity.
    Current (amps) is a measure of the AMOUNT of electricity.  
    Power (watts) is a measure of the WORK that electricity does per second.
    Resistance (ohms) is a measure of the resistance to the flow of current.
Ohm's Law (V=IR) relates Voltage, Current, and Resistance. Joule's Law (P=VI) relates Power to Ohm's Law.

Analogy
Electricity flowing through a wire is like water flowing through a garden hose. 
The pressure of the water is the voltage. This is controlled by how far open the faucet is.
The amount of water that is flowing through the hose is the current. This amount depends on the pressure and the resistance to flow.
The length and diameter of the hose is the resistance.
The amount of work that is done depends on both the amount and the pressure of the water (volts x amps = watts).

Microcontrollers 
It's a small computer commonly used to automate things. It reacts to an input (i.e. light sensors, buttons, motion sensors, infrared receivers, etc.) to control an output (ie: speaker, motor, lights, other microcontrollers, etc.).
In order of power and complexity:
    Custom chip < Arduino < Teensy < Raspberry Pi < Computer

AC vs DC
Alternating current (AC) is current that changes with time. An example of an AC source is a power outlet in a home (120 V).
Direct current (DC) is current that stays constant. An example of a DC source is a battery (12 V).

Electric Motors
They use electrical power to do mechanical work.
    AC motors - optimized for being plugged into wall (ie:shop tools)
    DC motors - things connected to batteries (ie: electric car)

Analog vs Digital
Analog is a continuous quantity that can change with time (think of a range of values, like a dial). Digital is a discrete quantity (think 1 or 0).
The vast majority of computing done today is digital in nature. A computer is basically millions or billions of electric switches working together.

Voltages:
    Arduino ~5 V
    motors 12-24 V
        Therefore, an Arduino usually requires a motor controller to safely and effectively run a motor.


Littlebits:

Colour-coded, modular magnetic pieces which connect together to make circuits (think Lego for electronics!)

Power = blue
    - Batteries
    - Wall connectors
    - USB cables

Inputs = pink
    - Switches, buttons and triggers:
        Switches
        Button
        Dimmers
        Pressure, bend and light sensors
        Timeout (timer)
        Pulse (stream of short on signals)
        Remote trigger (works with any infrared remote)
        Motion trigger
        Sound trigger (ie: clap on/off)
    - "Synth kit"- sound-related inputs:
        Envelope: modifies how long it takes to ramp up to max volume (attack) and how long it takes to fade to silence again (decay)
        Mix (combine two inputs and send them to a single output.  Has a level controller for each input.)
        Random (Noise mode = outputs white noise; random voltage = sends random voltage signals and needs a clock input like pulse or microsequencer)
        Delay (takes incoming audio and repeats it like an echo)
        Filter (affacts timbre by changing the relative volume of certain frequencies in the sound)
        Microsequencer and sequencer (controlling sequential patterns)
        Oscillator (creates various audio tones)
        Keyboard 
        Microphone

Outputs = green
   -  LEDs (including UV and Infrared LEDs) and lightwire 
   - Motors (DC and servo)
   - Buzzer
   - Bargraph
   - Fan
   - Synth speaker

Connections = orange
   - Wire
   - Branch
   - Fork
   - Latch (turns a button into an on/off switch - one press = on, second press turns off)
   - Inverter (gives opposite input signals to two outputs)
   - Wireless transmitter and receiver
   - Split
   - Cloud (connects to the internet, can communicate with another cloudbit over any distance)
   - Arduino  (connects to Arduini microcontroller, can upload code into the module
    Logic gates:
        Double OR:  If input one or input two receives an on signal, then it sends an on signal from its output
        Double AND: sends signal from output only when input one and input two are both receiving an on signal
        NOR:  output gives on signal only when neither input receives on signal 
        NAND: "not and" - output always gives an on signal unless both input one and input two are receiving an on signal
        XOR: "exclusive or" - sends an on signal exclusively from one output or the other, but not both

(give some time for participants to play around with the bits, build sample circuits on cards, etc.) 


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