This document discusses using Arduino with Ruby. It provides an overview of Arduino hardware and software, introduces RAD (Ruby Arduino Development) for writing Ruby code to control Arduino boards, and presents several example projects that combine Arduino and Ruby including Ruby on Bells, Barduino, and a Flying Robot. Code examples are provided for blinking an LED, fading an LED, reading an analog sensor, and using servos from Ruby. Additional sensors and shields discussed include Sharp IR sensors, ultrasonic rangefinders, and WiFi shields.

1. Arduino and Ruby
with a (tiny bit of) shoes
Martin Evans

2. Summary
• Arduino
• RAD (Ruby Arduino Development)
• Examples
• Projects

3. Arduino
• http://arduino.cc
• Examples
• Tutorials
• Downloads
• Forum

4. Hardware
Photo by adafruit - http://flic.kr/p/7LyorG

5. Photo by pt - http://flic.kr/p/7Luj6T

6. Duemilanove (2009)
• ATMega328p
• 60,000 sold 2009
• 6 Analog pins
• 14 Digital pins
• PWM: 3, 5, 6, 9, 10,
and 11.
• 16 Mhz
•
Photo by vouki - http://flic.kr/p/5V6KkG
Auto external Voltage

7. Diecimila (10 thousand)
• ATMega168
• 16 Mhz
• 14 digital I/O 6 pwm
• 6 Analog inputs
• 7 - 12 v
Photo by Remko van Dokkum - http://flic.kr/p/54JcXJ

8. Mega
• ATMega1280
• Analog 16 pins
• 54 Digital
• 14 PWM
Photo by Spikenzie - http://flic.kr/p/6ahHFu

9. Nano Lilypad
Mini
Photo by dodeckahedron - http://
flic.kr/p/3fM8aA

10. Photo by Osamu Iwasaki - http://flic.kr/p/79ymo7

11. Shields
• Ethernet
• Wifi
• Motor
• I/O
• Xbee
• Prototype
Photo by knolleary - http://flic.kr/p/4YaR9k

12. Motor controller
Photo by Alcoholwang - http://flic.kr/p/69yE7E

13. I/O Board
Photo by Alcoholwang - http://flic.kr/p/69yEch

14. Software
• Processing
• Basic IDE
• Cross platform
• Latest Version is 18

15. RAD
• Ruby Arduino Development
• Greg Borenstein 2007
• git://github.com/atduskgreg/rad.git
• http://github.com/madrona/rad

16. Installation
$ sudo gem install madrona-rad
$ rad example

18. Hardware.yml
############################################################
##
# Today's MCU Choices (replace the mcu with your arduino board)
# atmega8 => Arduino NG or older w/ ATmega8
# atmega168 => Arduino NG or older w/ ATmega168
# mini => Arduino Mini
# bt => Arduino BT
# diecimila => Arduino Diecimila or Duemilanove w/ ATmega168
# nano => Arduino Nano
# lilypad => LilyPad Arduino
# pro => Arduino Pro or Pro Mini (8 MHz)
# atmega328 => Arduino Duemilanove w/ ATmega328
# mega => Arduino Mega
---
serial_port: /dev/tty.usbserial*
physical_reset: false
mcu: atmega168

19. software.yml
---
arduino_root: /Applications/arduino-0015

20. Compile
rake make:upload

21. Getting Started with
Arduino
by Massimo Banzi

22. Blink LED
// Blinking LED
#define LED 13 // LED connected to
// Digital pin 13
void setup ()
{
pinMode(LED, OUTPUT); // sets the digital
// pin as output
}
void loop()
{
digitalWrite(LED, HIGH); // turns the LED on
delay(1000); // waits for a second
digitalWrite(LED, LOW); // turns the LED off
delay(1000); // waits for a second
}

23. Blink LED
class BlinkLed < ArduinoSketch
output_pin 13, :as => :led
def loop
blink led, 1000
end
end

24. Fade LED in and out
int ledPin = 9; // LED connected to digital pin 9
void setup() {
// nothing happens in setup
}
void loop() {
// fade in from min to max in increments of 5 points:
for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) {
// sets the value (range from 0 to 255):
analogWrite(ledPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect
delay(30);
}
// fade out from max to min in increments of 5 points:
for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5) {
// sets the value (range from 0 to 255):
analogWrite(ledPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect
delay(30);
}
}

25. Fade LED in and out
class Analogled < ArduinoSketch
output_pin 9, :as => :led
@i = 1
def loop
while @i < 255 do
analogWrite led, @i
@i +=5
delay 30
end
while @i > 0 do
analogWrite led, @i
@i -=5
delay 30
end
end
end

26. Blink LED analogue input
int sensorPin = 0; // select the input pin for the sensor
int ledPin = 13; // select the pin for the LED
int sensorValue = 0; // variable to store the value coming from
// the sensor
void setup() {
// declare the ledPin as an OUTPUT:
pinMode(ledPin, OUTPUT);
}
void loop() {
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
// turn the ledPin on
digitalWrite(ledPin, HIGH);
// stop the program for <sensorValue> milliseconds:
delay(sensorValue);
// turn the ledPin off:
digitalWrite(ledPin, LOW);
// stop the program for for <sensorValue> milliseconds:
delay(sensorValue);
}

27. Blink LED analogue input
class Analoginput < ArduinoSketch
output_pin 13, :as => :led
@val = 0
def loop
@val = analogRead(0)
digitalWrite (led, 1)
delay @val
digitalWrite (led, 0)
delay @val
end
end

28. Blink LED analogue input

29. Blink LED analogue input

30. Serial Read
class Serialcom1 < ArduinoSketch
input_pin 0, :as => :sensor
serial_begin :rate => 19200
def loop
serial_println analogRead sensor
delay 1000
end
end

31. Plugins and Libraries
• C Methods, directives,
external variables and
assignments and calls
that maybe added to
main setup method
• Arduino libraries

32. Servo code
class Servo < ArduinoSketch
output_pin 11, :as => :servo, :device => :servo
def loop
servo_refresh
servo.position 90
end
end

33. class Servo < ArduinoSketch
output_pin 11, :as => :my_servo, :device => :servo
def loop
servo_refresh
my_servo.position 180
servo_delay 1000
my_servo.position 0
servo_delay 1000
end
def servo_delay(t)
t.times do
delay 1
servo_refresh
end
end
end

34. Example Projects
Ruby on Bells
Barduino
Flying Robot

35. Ruby on bells
JD Barnhart

36. Ruby on Bells
JD Barnhart

37. Ruby on Bells
JD Barnhart

38. Barduino
Matthew Williams
http://github.com/mwilliams/barduino

39. Barduino
Photo by aeden - http://flic.kr/p/5uy7DX

40. Barduino

41. Barduino

42. Flying Robot
Damen and Ron Evans
http://wiki.github.com/deadprogrammer/flying_robot/
http://github.com/deadprogrammer/
flying_robot_blimpduino
http://deadprogrammersociety.blogspot.com/

43. Flying Robot
Photo by Austin Ziegler - http://flic.kr/p/6DXQqV

44. Flying Robot

45. Flying Robot

46. Shoes
• Snow Leopard Fail
• Toholio serial gem

47. Flying Robot code
• Background
• Draw images
• Serial update
• XBee

48. Shoes.setup do
gem 'toholio-serialport'
end
require "serialport"
require 'lib/flying_robot_proxy'
FLYING_ROBOT = FlyingRobotProxy.new

49. def draw_background
@centerx, @centery = 126, 140
fill white
stroke black
strokewidth 4
oval @centerx - 102, @centery - 102, 204, 204
fill black
nostroke
oval @centerx - 5, @centery - 5, 10, 10
stroke black
strokewidth 1
line(@centerx, @centery - 102, @centerx, @centery - 95)
line(@centerx - 102, @centery, @centerx - 95, @centery)
line(@centerx + 95, @centery, @centerx + 102, @centery)
line(@centerx, @centery + 95, @centerx, @centery + 102)
@north = para "N", :top => @centery - 130, :left => @centerx - 10
@south = para "S", :top => @centery + 104, :left => @centerx - 10
@west = para "W", :top => @centery - 12, :left => @centerx - 126
@east = para "E", :top => @centery - 12, :left => @centerx + 104
end

50. def draw_compass_hand
@centerx, @centery = 126, 140
@current_reading = @compass.to_f #[17, @compass.length].to_f
return if @current_reading == 0.0
# the compass is oriented in reverse on the blimpduino, so switch it
@current_reading = (@current_reading + 180).modulo(360)
_x = 90 * Math.sin( @current_reading * Math::PI / 180 )
_y = 90 * Math.cos( @current_reading * Math::PI / 180 )
stroke black
strokewidth 6
line(@centerx, @centery, @centerx + _x, @centery - _y)
end

51. Sharp GP2D12
Photo by hmblgrmpf - http://flic.kr/p/hJmoM

52. Sharp GP2D12 code
class Sharpir < ArduinoSketch
# Analog input for sharp Infrared sensors GP2D12
input_pin 0, :as => :ir_sensor_right
# variables for checking for obstruction
@range = "0, int"
serial_begin
def loop
range_ir_sensor
delay 10
end
def range_ir_sensor
@range = analogRead(ir_sensor)
if (@range> 3) then
@range = (6787 / (@range - 3)) - 4
serial_print "sensor: "
serial_println @range
delay 1000
end
end
end

53. Devantech SRF05
Photo by Lucky Larry - http://flic.kr/p/6E5pZZ

54. Devantech SRF05
class Rangefinding < ArduinoSketch
@sig_pin = 2
serial_begin
def loop
serial_println(pingsrf05(@sig_pin))
end
end

55. class Srf05 < ArduinoPlugin
# Triggers a pulse and returns distance in cm.
long pingsrf05(int ultraSoundpin) {
unsigned long ultrasoundDuration;
// switch pin to output
pinMode(ultraSoundpin, OUTPUT);
// send a low, wait 2 microseconds, send a high then wait 10us
digitalWrite(ultraSoundpin, LOW);
delayMicroseconds(2);
digitalWrite(ultraSoundpin, HIGH);
delayMicroseconds(10);
digitalWrite(ultraSoundpin, LOW);
// switch pin to input
pinMode(ultraSoundpin, INPUT);
// wait for a pulse to come in as high
ultrasoundDuration = pulseIn(ultraSoundpin, HIGH);
return(ultrasoundDuration/58);
}
end

56. Wishield
Asynclabs

57. Pachube
• http://www.pachube.com
• Sign up for account
• Get api key
• http://www.pachube.com/feeds/6445

58. Roo-bee
• Obstacle avoidance
• Sharp IR sensors
• Arduino Duemilanove
• Devantech SR05 Ultrasound
• Servo
• Solarbotics Motors

63. DEMO

64. Suppliers
• Active robots: http://active-robots.com
• Ebay jzhaoket and yerobot
• http://asynclabs.com
• http://bitsbox.co.uk

65. Thanks
• Github http://github.com/lostcaggy
• Slides will be on slideshare later