Programming in Arduino

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Programming in Arduino
Pre Pres. Notes
Casperelectronics
Photos from workshop?
MaterialsArduino Board
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• Arduino.cc has the IDE programming software for
  free download

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Arduino Sketch

• Arduino files are called sketches.
• Arduino sketches must be compiled in the IDE
  before being downloaded to the Arduino board.

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Program Structure

• Two required functions in an Arduino sketch,
  setup() and loop().
• setup() The function is called when your program
  starts. Use it to initialize your variables, pin
  modes, start using libraries, etc. The setup
  function will only run once, after each powerup
  or reset of the Arduino board.
• Loop() After creating a setup() function, which
  initializes and sets the initial values, the
  loop() function does precisely what its name
  suggests, and loops consecutively, allowing your
  program to change and respond. Use it to actively
  control the Arduino board.

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What does void mean

• The void keyword is used only in function
  declarations. It indicates that the function is
  expected to return no information to the function
  from which it was called.

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Libraries

• Extend the capabilities of Arduino IDE
• Offer simpiler ways of controlling hardware they
  are written for.
• Advanced. will talk about later.

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Variables

• Let you store a value.
• Must declare variables and tell computer what
  kind of value to expect.
• Int- number between -32,768 to
  32,767
• Byte- 0 -255
• char- type character
• and more

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Int variable

• int- an integer is a whole number (1,2,3,25)
• are your primary datatype for number storage, and
  store a 2 byte value (take 2 bytes of memory).
  This yields a range of -32,768 to 32,767
• example
• int ledpin 13 // sets the variable named
  ledpin to 13

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Char variable

• char- A data type that takes up 1 byte of memory
  that stores a character value.
• Both of these are equivalent and refer to the
  letter A
• char myChar 'A'
• char myChar 65 in ASCII

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Byte variable

• Byte- an integer between 0 and 255 (byte uses
  less memory, only 1 byte)
• Made up of 8 bits.

Example in binary 00000001, 00000011
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Binary Numbering (how computers count)

• If computers only know 1 and 0 how do they form
  complex operations?
• 128 64 32 16 8 4 2 1
• 00000001 1
• 00000010 2
• 00000011 3
• 00000100 4

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Programming- Functions

• Segmenting code into functions allows a
  programmer to create modular pieces of code that
  perform a defined task and then return to the
  area of code from which the function was
  "called".
• Existing Functions- commands Arduino
  automatically understands
• Custom Functions -The typical case for creating a
  function is when one needs to perform the same
  action multiple times in a program.

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Example FunctionspinMode(), digitalWrite(), and
delay()

• The pinMode() function configures a pin as either
  an input or an output.
• pinMode(ledPin, OUTPUT) // sets
  the digital pin as output
• The digitalWrite() function outputs a value HIGH
  or LOW on a pin. For example, the line
• digitalWrite(ledPin, HIGH) //sets pin
  high
• The delay() causes the Arduino to wait for the
  specified number of milliseconds before
  continuing on to the next line. There are 1000
  milliseconds in a second, so the line
• delay(1000) // creates a delay of
  one second.

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Pseudocode Blink an Led

• 
  English
• I want an led to blink, on for a second and off
  for a second forever.
• 
  Pseudocode
• Turn led on
• wait
• Turn led off
• Loop again

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Pseudocode Translation

• void loop() // run over and
  over again
• digitalWrite(ledPin, HIGH) // sets the LED
  on
• delay(1000) // waits for a
  second
• digitalWrite(ledPin, LOW) // sets the LED
  off
• delay(1000) // waits for a
  second

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Blink an Led(w/o comments)

• int ledPin 13
• void setup()
• pinMode(ledPin, OUTPUT)
• void loop()
• digitalWrite(ledPin, HIGH)
• delay(1000)
• digitalWrite(ledPin, LOW)
• delay(1000)

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Blink an Led

• int ledPin 13 // LED connected
  to digital pin 13
• void setup() // run once, when
  the sketch starts
• pinMode(ledPin, OUTPUT) // sets the
  digital pin as output
• void loop() // run over and
  over again
• digitalWrite(ledPin, HIGH) // sets the LED
  on
• delay(1000) // waits for a
  second
• digitalWrite(ledPin, LOW) // sets the LED
  off
• delay(1000) // waits for a
  second

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• Demo Programming board

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HW Bring in a video or webpage link that is
related to Physical Computing that you think is
interesting and be prepared to talk about it in
class.