Arduino: Open Source Hardware Hacking from the Software Nerd Perspective

Arduino: Open
Source Hardware
Hacking from the
Software Nerd
Perspective
Howard M. Lewis Ship
TWD Consulting
hlship@gmail.com
1 © 2010 Howard M. Lewis Ship

Qualiﬁcations


Me

Hardware


~ 1980
• 6502 CPU
• 8 bit accumulator
• Two 8 bit registers
• 1 MHz
• 8 KB Ram (Upgrade!)
• 30x30 B/W display
• 300 baud cassette


Hot End

OSCON
2009


http://www.makershed.com/ProductDetails.asp?ProductCode=MKCE4

Open Source …
Hardware?


In addition, the IDE is free and open source, as is the bootloader that gets your code from the IDE and onto the Arduino.

Digital
Analog
CPU / Clock Flash RAM EEPROM Pins /
Pins
PWM

ATmega 328 /
Duemilanove 32 KB 2 KB 1 KB 14 / 6 6
16 MHz

ATmega1280
MEGA 128 KB 8 KB 4 KB 54 / 14 16
/ 16 MHz

ATmega 168 /
16 KB 1 KB 512 B 14 / 6 6
16 MHz


http://arduino.cc/

http://www.dorkbotpdx.org/wiki/dorkboard

Baby Steps: LED

Arduino


LED is Light Emitting Diode. Diodes are one-way elements (electricity does not ﬂow backwards).

The long pin is the anode, which connects to positive current.

The short pin is the cathode, which connects to negative current (the ground).

The glass enclosure usually has a ﬂat side to indicate the cathode.

http://en.wikipedia.org/wiki/Led

Your Code

Frameworks

Application
Server

Virtual Standard
Machine Library

Operating
HAL Drivers
System

BIOS

Hardware

Your Code


Your Code

Standard Library Add-on Libraries

Hardware: Arduino Microcontroller / Switches, Sensors, etc.


Button

Arduino Vcc


#define LED_PIN 11
#define BUTTON_PIN 7

void setup()
{
pinMode(LED_PIN, OUTPUT);
pinMode(BUTTON_PIN, INPUT);
}

void loop()
{
digitalWrite(LED_PIN, digitalRead(BUTTON_PIN));
}


?

Arduino Vcc


240 Ω
10000 Ω

Arduino Vcc


Analog Input

ARef

Arduino
Analog 5


The center pin is the output pin. The Arduino reads it as a value between 0 and 1023.

The other pins are connected to the Arduino's AREF (Analog Reference) voltage pin, and to ground.

#define LED_PIN 11
#define POT_PIN 5

void setup()
{
pinMode(LED_PIN, OUTPUT);
}

void loop()
{
int potValue = analogRead(POT_PIN);

analogWrite(LED_PIN, potValue >> 2);
}

Pulse Width Modulation

Scaling Up


Shift Register
Shift Register
Arduino


http://en.wikipedia.org/wiki/Shift_register

LED Digit
1 16

2 32

4 64

8 128


const int latchPin = 11; // ST_CP (12)
const int clockPin = 10; // SH_CP (11)
const int dataPin = 9; // DS (14)

boolean status = false;

byte ledValue = 0;

void setup()
{
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
}


const byte digits[] = {
B01111110, // 0
B00001100, // 1
B10110110, // 2
B10011110, // 3
B11001100, // 4
B11011010, // 5
B11111010, // 6
B00001110, // 7
B11111110, // 8
B11001110, // 9
B10111110, // A
B11111000, // B
B10110000, // C
B10111100, // D
B11110010, // E
B11100010 // F
};


void writeDigit(byte value, boolean showDP)
{
// Ignore all but the low 4 bits when indexing
byte digit = digits[value & 0x0f];

// Decimal point is LSB
if (showDP)
digit |= 1;

shiftOut(dataPin, clockPin, MSBFIRST, digit);
}


void loop()
{
status = !status;

digitalWrite(latchPin, LOW);

writeDigit(ledValue >> 4, status == true);
writeDigit(ledValue, status == false);

digitalWrite(latchPin, HIGH);

ledValue++; // Increment, loop back to zero

delay(128);
}


Next Steps ...
• More interesting sensors
• Motion sensor
• Optical switches
• Accelerometer
• GPS
• more!
• … and displays (8x8 RGB Matrix)


Getting Started with Arduino: http://oreilly.com/catalog/9780596155520

Practical Arduino: http://www.practicalarduino.com/

Practical Electronics for Inventors: http://www.mhprofessional.com/product.php?isbn=9780071452816

Understand Electronics: http://www.amazon.com/Understand-Electronics-Teach-Yourself-Guide/dp/0071740015

Summary

• Easy to get started!
• Don't Fear the Soldering Iron
• Be in control!
• Have fun!


Slides

• Will be available on SlideShare
http://www.slideshare.net/hlship

• … and rate me at SpeakerRate:
http://speakerrate.com/speakers/3749-
howard-m-lewis-ship


© 2006 Kevin Jaako
http://www.flickr.com/photos/jaako/111131894/
© 2009 Adam Evans
http://www.flickr.com/photos/astroporn/3918373246/
© 2006 jopemoro
http://www.flickr.com/photos/jopemoro/81013003/
© 2008 shane doucette
http://www.flickr.com/photos/51512551@N00/3027058889/
© 2006 Nelson Minar
http://www.flickr.com/photos/nelsonminar/302035574/
© 2008 Thomas Hawk
http://www.flickr.com/photos/thomashawk/2598531205/
© 2009 dnnya17
http://www.flickr.com/photos/dnnya/3462481080/
© 2006 Iain Fergusson
http://en.wikipedia.org/wiki/File:Potentiometer.jpg


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