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Intro to Arduino - RPI Embedded Hardware Club

Intro to Arduino - RPI Embedded Hardware Club

RPI Embedded Hardware Club
http://rpiEHC.org

Intro to Arduino Workshop
Held March 7, 2013 @ 7-9pm in Sage 2202
Open to campus

Contact Theo Pak
[email protected]

Theo Pak

March 07, 2013
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Transcript

  1. INTRO TO ARDUINO
    rpiEHC.org | March 7, 2013
    In this photo you can see a pushbutton with a pull-up resistor, an LED, a 2x16
    character display, and 4 potentiometer knobs. This is the winning project from EHC's
    Silicon Chef competition last November. The 4-person team designed and built a
    small lock box in just 5 hours. They used an Arduino Nano microcontroller for the
    whole thing.
    If you need to use a microcontroller, you should consider an Arduino. The Arduino
    "brand" of microcontrollers all run the same code and are widely available online, at
    RadioShack, and here at Embedded Hardware Club. Arduinos are very easy to use
    and there's a big open-source community where you can find pre-written code to do
    just about anything.
    Chances are that if you want to make your microcontroller do a task, someone on the
    internet has already done it with an Arduino. And they wrote a tutorial that you find
    online.
    Photo credit Ethan Spitz. Resistor (BwBkOG) is 10kΩ ± 5%.

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  2. THEO PAK
    President,
    RPI Embedded Hardware Club
    Class of 2015
    CSYS/CSCI
    [email protected]
    RPI Embedded Hardware Club
    http://rpiEHC.org
    Intro to Arduino Workshop
    Held March 7, 2013 @ 7-9pm in Sage 2202
    Open to campus
    Contact Theo Pak
    [email protected]

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  3. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O

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  4. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O

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  5. ● Very easy to use.
    ● Buy them now, for cheap.
    ● Tons of code already exists.
    ● Generally appropriate for real-time.
    ● They're not the most powerful.
    ● Other options use less electricity.
    WHY USE AN ARDUINO?
    The Arduino platform is a great candidate. Weigh the pros and cons of using one to
    meet your needs.
    But they're not the best for everything -- you may find that you need an ultra-low-
    power solution or something with a more beefy processor. Maybe you need tons of
    memory. Maybe you're a sadist and you don't like the convenience of open-source
    platforms.
    Whatever your needs are, Embedded Hardware Club can help you find a solution.
    Today I'll talk about Arduinos.

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  6. INSTALL THE ENVIRONMENT
    An Integrated Development Environment
    includes a code editor, compiler, and
    debugger. You need all three!
    The Arduino Team makes an IDE.
    Download it at http://arduino.cc
    If you are using an older Arduino you will also need the FTDI drivers. They can be
    found online. Windows 7 will download them automatically.
    As of today, the most recent stable version is 1.0.3. I'll demo using that on Windows
    7.
    Now you can connect the USB cable to your computer.

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  7. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O

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  8. PROGRAMMING 101
    /* Comments describe code to humans */
    void setup () {
    /* this part runs once */
    }
    void loop () {
    /* this part runs infinitely */
    }
    This is the skeleton for all Arduino programs.
    Type it into your editor now.

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  9. SELECT THE RIGHT BOARD
    Auto Format
    Archive Sketch
    Fix Encoding & Reload
    Serial Monitor
    Board
    Serial Port
    Programmer
    Burn Bootloader
    Arduino Uno
    Arduino Duemilanove
    Arduino Diecimila
    Arduino Nano /atmega328
    Arduino Something else
    Arduino Mega
    Arduino Leonano
    Powahduino
    Tools >>

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  10. SELECT THE RIGHT PORT
    Tools >> Auto Format
    Archive Sketch
    Fix Encoding & Reload
    Serial Monitor
    Board
    Serial Port
    Programmer
    Burn Bootloader
    COM3
    COM4
    COM6
    /dev/ttyUSB1
    /dev/ttyCOM1
    Arduino WTF
    Arduino Leonano
    Unix is cool!
    Windows users may want to open the "Device Manager" from the control panel.

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  11. UPLOAD A TEST PROGRAM!
    Arduino Version 1.0 Arduino Version Before 1.0

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  12. Arduino Version 1.0 Arduino Version Before 1.0
    UPLOAD YOUR CODE
    WITH THIS BUTTON

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  13. HOW TO PRINT A MESSAGE
    void setup () {
    // Begin serial communication
    // at 9600 BAUD
    Serial.begin(9600);
    }
    void loop () {
    // Print the line "hello world"
    Serial.println("hello world");
    }
    Type these 2 lines of code into your program.
    That's it! Easy!
    Note that case matters. You need a capital "S" in "Serial".

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  14. THE SERIAL MONITOR
    Arduino Version 1.0 Arduino Version Before 1.0
    Open the serial Monitor
    The "serial monitor" is a window of text that lets your laptop communicate with the
    board.
    It's very useful when debugging your code.

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  15. WTF IS A BAUD RATE?
    Bandwidth

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  16. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O
    What does "digital" mean? Digital means that the signal is one of two states: either
    HIGH or LOW. There's only ones and zeros! Nothing else exists.
    Contrast digital values with analog values, which are real. For example, an analog
    signal could be 2.4V or 7V. A digital signal can only be TRUE or FALSE.

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  17. It's not made of food!
    Breadboards let you
    quickly build a circuit
    without using any tools.
    WHAT'S A BREADBOARD?
    What does a breadboard taste like?
    Plastic and metal, mostly. These reusable solderless prototyping boards are not
    meant to be eaten. The name is an homage to the good ol' days when amateur radio
    enthusiasts had to staple copper wire to wooden boards in order to test their circuits.
    Breadboards allow you to quickly build a circuit without using any tools. We'll use one
    to build a test circuit.

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  18. Here's the inside of a breadboard. It's very simple.
    Photograph via http://www.protostack.com/blog/2011/09/8-breadboard-hacks/

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  19. DIGITAL OUTPUT: PLUG IN THE LED
    Switch on D5, LED on D13
    Use your breadboard to connect an LED to your arduino.
    Everything here is pretty arbitrary, based on what's available today.

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  20. FLASH AN LED
    void setup () {
    pinMode(13,OUTPUT);
    }
    void loop () {
    // Turn LED on
    digitalWrite(13,HIGH);
    delay(100); // Wait 100 milliseconds
    // Turn LED off
    digitalWrite(13,LOW);
    delay(100); // Wait 100 milliseconds
    }
    Remember that Arduinos come with a built-in LED that's automatically connected to
    pin D13. You can still use D13 for other things, but there's always an LED connected
    to it.

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  21. PUSHBUTTONS AS INPUT
    void setup () {
    pinMode(13,OUTPUT); // Configure Pin13 as output
    pinMode(5,INPUT); // Configure Pin5 as input
    }
    void loop () {
    // If the button is pressed...
    if (digitalRead(5)) {
    // ...then turn LED on
    digitalWrite(13,HIGH);
    } else {
    // ...if not, the turn LED off
    digitalWrite(13,LOW);
    }
    }
    A pushbutton has two states: pressed or not pressed. This means that PBs are digital!

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  22. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O
    Analog signals come from real stuff.
    For example, if you're using a load cell to sense a weight then you need to read an
    exact analog voltage level from within the range. Your load cell might give you 2.4V
    when it's feeling 2 lbs and 5V when it's feeling 10 lbs.

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  23. POTENTIOMETERS AS INPUT
    void setup () {
    // Configure the serial monitor
    Serial.begin(9600);
    // We'll use the default settings for
    Analog1
    }
    void loop () {
    // read the 10 bit value from Analog1
    int value = analogRead(1);
    // write the value to serial
    Serial.println(value);
    }
    A potentiometer is a variable resistor. They turn like a little knob.
    Because potentiometers have variable resistance, they can be used to vary voltage.
    This is how pots can be used to give analog input.
    You might use a potentiometer like a knob to be an input on your system.
    Alternatively, consider a rotary encoder.

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  24. MORE ABOUT ANALOG INPUT
    void setup () {
    Serial.begin(9600); // Begin serial
    communication
    pinMode(14,OUTPUT); // Pin14 is...
    digitalWrite(14,LOW); // Start Pin14 LOW
    pinMode(16,OUTPUT); // Pin16 is...
    digitalWrite(16,HIGH); // Start Pin16 HIGH
    }
    Analog pins 0-5 can be used as digital pins, if configured.
    Add 14 to the analog pin number and it acts like a digital pin
    This trick makes hooking up the pot easier in this example
    You can use Arduino analog pins for digital I/O, but you can't use digital pins for
    analog I/O.

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  25. NOW BACK TO POTS
    void setup () {
    Serial.begin(9600);
    pinMode(14,OUTPUT);
    digitalWrite(14,LOW);
    pinMode(16,OUTPUT);
    digitalWrite(16,HIGH);
    }
    void loop () {
    // read the 10 bit value from Analog 1
    int value = analogRead(1);
    // write the value to serial
    Serial.println(value);
    }

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  26. 1. GETTING STARTED
    2. UPLOADING CODE
    3. DIGITAL I/O
    4. ANALOG I/O

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  27. 5. BONUS!
    We have more use cases for you!

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  28. ALL ABOUT PWM
    Voltage vs. Time: The PW
    defines a servo position.
    What if you need to send an analog signal out? That's not how microcontrollers work!
    But you can approximate an analog signal with techniques like pulse-width
    modulation. All digital electronics use these kinds of signals when you want to
    approximate an analog waveform by using only ones and zeros.
    For example, you can send a PWM signal to a motor controller in order to "tell it" a
    specific position.
    An audio signal can be represented as a series of pulses where faster sample rates
    have more pulses per period.
    Image via http://www.servocity.com/html/how_do_servos_work_.html

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  29. PULSE-WIDTH MODULATION
    void setup() {
    pinMode(3,OUTPUT);
    }
    void loop() {
    // send pulses to pin 3
    // 128 of 256 should be high
    analogWrite(3,128);
    }
    There are many different aspects of PWM-type signals. The built-in Arduino libraries
    make it easy to approach many of these.
    Without the Arduino libraries, you would need to write many many lines of code to
    generate this signal (using a programmable counter array, maybe). Have you taken
    Laboratory Introduction to Embedded Control? This is way easier.

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  30. PWM WITH FADING
    void setup() {
    pinMode(3,OUTPUT);
    }
    void loop() {
    for (int i = 0; i < 256; i++) {
    // send pulses to pin 3
    analogWrite(3,i);
    // delay each loop
    delay(100);
    }
    }
    A "for loop" is a common programming pattern. It's kind of a shortcut for a "while
    loop".
    Loops allow you to do repetitive tasks with just a few lines of code. As a programmer,
    you'll also find them easier to read. Never hard-code what you can do with a loop!

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  31. PPM FOR SERVO CONTROL
    #include
    Servo myservo; //create servo object to control a servo
    void setup () {
    myservo.attach(9); //attach pin 9 to the servo
    object
    }
    void loop () {
    for (int i = 0; i < 255; i ++) {
    // set the servo position
    myservo.write(i);
    // wait for the servo to get there
    delay(15);
    }
    }
    We were lying to you when we said that servos use PWM. They actually use PPM
    signals, which are a specific signal that's like PWM.
    PPM = Pulse Position Modulation
    PWM varies the width of a pulse within each discrete frame of time, ie the Duty Cycle.
    PPM varies how often each pulse appears.

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  32. PPM FOR SERVO CONTROL
    This slide gives extra information. PWM is generally confusing enough without this
    much detail...
    PPM = Pulse Position Modulation
    PWM varies the width of a pulse within each discrete frame of time, ie the Duty Cycle.
    PPM varies how often each pulse appears. Basically, it gives more powah!
    Images via http://www.endurance-rc.com/ppmtut.php

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  33. SERIAL INPUT
    String inputString = ""; // a string to hold incoming data
    boolean stringComplete = false; // whether the string is complete
    void setup() {
    // initialize serial:
    Serial.begin(9600);
    // reserve 200 bytes for the inputString:
    inputString.reserve(200);
    }
    void loop() {
    // print the string when a newline arrives:
    if (stringComplete) {
    Serial.println(inputString);
    // clear the string:
    inputString = "";
    stringComplete = false;
    }
    }
    You can use the serial port for other things, too.

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  34. SERIAL EVENT
    void serialEvent() {
    while (Serial.available()) {
    // get the new byte:
    char inChar = (char)Serial.read();
    // add it to the inputString:
    inputString += inChar;
    // if the incoming character is a newline, set a
    flag
    // so the main loop can do something about it:
    if (inChar == '\n') {
    stringComplete = true;
    }
    }
    }
    This is awesome! Here's an example case: https://sites.google.
    com/site/caribouvending/

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  35. QUESTIONS?
    RPI Embedded Hardware Club
    http://rpiEHC.org
    Intro to Arduino Workshop
    Thursday, March 7, 2013
    Theo Pak
    Thanks!

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  36. Arduino Nano – $25 each

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  37. Please install the Arduino
    software. You can find it at
    arduino.cc/en/Main/Software

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  38. UPCOMING WORKSHOPS
    Thur March 21
    Thur March 28
    Thur April 4
    SENSORS AND ACTUATORS
    THROUGH-HOLE SOLDERING
    INTERMEDIATE PIC

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  39. BOOKMARK RPI EHC. ORG
    Thursday, March 21 is our
    SENSORS AND ACTUATORS
    workshop hosted by EHC member
    David Herbert. Learn more uses of
    inputs, servos, and steppers.

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