unlondon-workshops/presentations/workshop-may-2016/talk.md

---
author: Fred Cahill, Shawn Nock
institute: Unlondon Digital Media Assoc.
title: Arduino for the Arts
lang: en-CA
colorlinks: true
...

# What's in your kit?

## Kit Contents

- Arduino Uno R3 Clone
- Solderless Breadboard
- Connecting wires
- LEDs
- Resistors, Potentiometer
- Buzzer
- IR Remote
- IR Receiver

## What is Arduino?

\begin{center}
$\mu$C + reset button + led + USB communication
\end{center}

It's a kit (on a board) with the bare minimum components to easily use the $\mu$C
hardware. They do the basic, boring design needed for any board, so users only
need to add the neat stuff.

## Arduino UNO

The Arduino variety that we are using is the Arduino UNO.

- Processor: Atmel Atmega328p
- Memory: 2K RAM + 32K Flash
- FT232RL Logic-level Serial$\leftrightarrow$USB Chip

## Arduino Software

The Arduino folks also adapted an *Integrated Development Environment*
(IDE) to their boards. This IDE allows users to easily write programs
for their boards and then write the programs to the $\mu$C.

\Large Get the Arduino IDE: [https://www.arduino.cc/en/Main/Software](https://www.arduino.cc/en/Main/Software)

# Circuit Basics

## Diode

\begin{columns}[c]
\column{0.50\textwidth}

\begin{itemize}
\item One way value for current\footnotemark[1]
\item LED $\equiv$ Light Emitting Diode
\item Band marks (-)\footnotemark[2]
\item Longer leg marks (+)
\end{itemize}

\column{0.50\textwidth}
\begin{center}
\includegraphics[width=0.75\textwidth]{images/diode.png}
\vspace{5mm}
\includegraphics[width=0.50\textwidth]{images/led.jpg}
\end{center}
\end{columns}

\footnotetext[1]{\tiny \url{https://learn.sparkfun.com/tutorials/diodes}}
\footnotetext[2]{\tiny \url{https://learn.sparkfun.com/tutorials/polarity/diode-and-led-polarity}}

## Diode Problems

* Diodes don't limit current
* Diodes aren't perfect (some current turned to heat)
* Too much current = Too much heat = __BANG__
* How do we limit current?

## Resistor

\begin{columns}[c]
\column{0.50\textwidth}

\begin{itemize}
\item \emph{Resist} the flow of current
\item Needed for LEDs: $\approx\SI{400}{\ohm}$\\
(safe for $\le\SI{6}{\volt}$)
\item Button Pull-up/down: $\ge\SI{10}{\kilo\ohm}$
\item Color coded, Google it
\end{itemize}
\column{0.50\textwidth}

\includegraphics[width=0.98\textwidth]{images/resistor.png}

\end{columns}

## Ohm's Law

Ohm's Law relates current to potential and resistance.

$$ V = IR $$
$$ I=\frac{V}{R} $$
$$ R = \frac{V}{I} $$

* V = Potential in Volts (\si{\volt})
* I = Current in Amperes (\si{\ampere})
* R = Resistance in Ohms (\si{\ohm})

## Ohm's Law: Example

The datasheet for an LED says that the maximum continuous current is
\SI{15}{\milli\ampere}. Your circuit operates at \SI{5}{\volt}\footnotemark[1]. How
big should your resistor be?

$$ \si{\ohm} = \frac{\SI{5}{\volt}}{\SI{0.015}{\ampere}} = 333.\overline{3}\si{\ohm} $$

How much current for our *cheet sheet* value?

$$ \si{\ampere} = \frac{\SI{5}{\volt}}{\SI{400}{\ohm}} = \SI{12.5}{\milli\ampere} $$

\footnotetext[1]{\tiny Actually, this calculation is inaccurate. LEDs will have a *forward voltage drop* of between \SI{300}{\milli\volt} and \SI{700}{\milli\volt} this should be subtracted from \si{\volt} above... but it's not critical.}

## Buttons

- Buttons connect _or_ disconnect two wires/parts
- Momentary Switch: Normally Closed (NC), Normally Open (NO) 
- Toggle Switch

## Digital Signals

- Vcc: The power supply of the digital circuit elements
- GND: The reference voltage (usually \SI{0}{\volt})
- Connecting a part to Vcc = Logical 1
- Connecting to GND = Logical 0

## Transducers {.fragile}

Transducers turn electrical energy into another sort of energy:

| |
-------|--------:
Speaker|Electrical $\rightarrow$ Sound
Microphone|Sound $\rightarrow$ Electrical
LED|Electrical $\rightarrow$ Light
LED|Light $\rightarrow$ Electrical
Piezoelectric|Electrical $\rightarrow$ Motion

## Piezo Buzzer

- Piezoelectric elements change shape when voltage is applied
- Thin discs can be made to oscillate and create sound.
- Contains oscillator circuit
- Two connections: Vcc, GND
- Use a switch; connected = annoying tone, disconnected = glorious silence


## Power

The power supply provides the energy to drive the system *and* defines logical 1.

Can be a:

* Voltage Regulator (converts one potential to another)
* Batteries (Lemon, NiMH, LiPo)
* Solar Panel

In our circuits, your laptop is converting it's power source to 5V and
delivering power to our circuit via USB. You also have a battery pack
for computer-free shenanigans.

## $\mu$Controller

Microcontroller ($\mu$C) is a *processor*, *memory* and a few *peripherals* on a standalone
chip.

Processor 
:    is a group of transistors that understands a few dozen
commands (ADD, SUB, JUMP..)

Memory
:    a circuit that can hold values.

Peripherals
:    Vary chip to chip, but often include timers, radios, communication interfaces

Seems complicated, but really simple. They literally read a command
(and data) from memory, then execute the command. At the end of the
command, the next command is read from the next memory cell and the
process is
repeated^[some commands change the next command memory address]

# Let's start programming

## Configure Arduino

\begin{center}
\includegraphics[width=0.98\textwidth]{images/arduino-board.png}
\end{center}

* Board: Arduino UNO
* Processor: ATmega328
* Port: \ldots

## The Code Environment

\begin{center}
\includegraphics[width=0.5\textwidth]{images/arduino-toolbar.png}
\end{center}

## Your first Program

~~~ C
/* the setup function runs once on reset / power */
void setup() {
  /* set pin 13 as an output */
  pinMode(13, OUTPUT);
}

/* the loop function repeats forever */
void loop() {
  digitalWrite(13, HIGH);   // turn on LED
  delay(1000);              // wait for a second
  digitalWrite(13, LOW);    // turn the off LED
  delay(1000);              // wait for a second
}
~~~

## Buzzer: Hardware

\begin{center}
\includegraphics[width=0.98\textwidth]{images/buzzer-breadboard.png}
\end{center}

## Buzzer: Software

~~~ C
#define BUZZER 8       /* Make BUZZER same as pin 8 */

void setup() {
  pinMode(BUZZER, OUTPUT);
  digitalWrite(BUZZER, HIGH);    /* Turn off buzzer */
}
void loop() {
  digitalWrite(BUZZER, LOW);      /* Turn on buzzer */
  delay(100);                     /* wait for 100ms */
  digitalWrite(BUZZER, HIGH);    /* Turn off buzzer */
  delay(900);                         /* wait 900ms */
}
~~~

## Push Button: Hardware

\begin{center}
\includegraphics[width=0.98\textwidth]{images/buzzer-button-breadboard.png}
\end{center}

## Push Button: Software (Part 1)

~~~ C
#define BUTTON 7
#define BUZZER 8

int button_state = 0;

void setup() {
  pinMode(BUTTON, INPUT);
  pinMode(BUZZER, OUTPUT);
  digitalWrite(BUZZER, HIGH);
}
~~~

## Push Button: Software (Part 2)

~~~ C
void loop() {
  button_state = digitalRead(BUTTON);
  if (button_state == HIGH) {
    digitalWrite(BUZZER, LOW);
  } else {
    digitalWrite(BUZZER, HIGH);
  }
}
~~~

## The End?

\begin{center}
\LARGE{Questions?}
\end{center}