en-1.3

Arduino 101First steps in hardware hacking

Program

• Introductions

• What can you do with Arduinos?

• First circuit: Blink

• Coding Dojo with Arduino

• ABCofE: ABC of Electronics

• Tra!c light circuit

• Wrapping up

2

Introductions

3

Luciano Ramalho

• Consultant, teacher and speaker specializing in the Python language

4

Luciano Ramalho

• Self-taught programmer since 1978

• BASIC, ASM Z-80, Pascal, C, C++, Smalltalk, Perl, Java, Python, JavaScript, Ruby...

• Bachelors degree in Library and Information Sciences from ECA/USP

• Art and Programming Workshop (PSI-2615) at Poli/USP with Prof. Etienne Delacroix

5

Luciano Ramalho

• Owner and teacher of O"cinas Turing

• Partner and instructor at Python.pro.br

• Founding member of Garoa Hacker Clube

Turing.com.broficinas

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Introduce yourselves

• Find out the name, interests and hobbies of the people near you

• Ask and tell your neighbors:

• Why are you interested in Arduinos?

• Do you have a project in mind?

5 minutes

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Census

• Who knowsa lot about electronics?

• Who knowssomething about electronics?

• Who knowsa lot about programming?

• Who knowssomething about programming?

8

Census

nothing some a lot

3 2 2

0 2 3

0 1 0LR

Elec

tro

nics

Programming

noth

ing

som

ea

lot

9

What can you do with Arduinos?

10

Rep

Rap

3D

pri

nter

Open hardware Self-replicating!

Open hardware

• Open hardware: free and open schematics and software + o#-the-shelf or home made components

• Arduino is open hardware: copying is legal

• Use of the Arduino brand: only under license

Bike

r tu

rn s

igna

l

ArduinoLilypad

Leah Buechley of MIT

• Breathalyzer-Microphonewww.instructables.com/id/Breathalyzer-Microphone/

• Guitar Pedalwww.instructables.com/id/Lo-"-Arduino-Guitar-Pedal/

• Balancing Robot (inspired by Segway)hacknmod.com/hack/make-a-mini-segway-using-the-arduino/

• High-speed photography triggerhacknmod.com/hack/high-speed-photography-how-to-trigger-using-arduino/

• Home automationwww.makeuseof.com/tag/how-to-build-home-automation-system-raspberry-pi-and-arduino/

Sim

ple

proj

ects

14

15

That’s why the logo is∞

Parts

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A kit to get started

LEDs 7-segment display 9g micro-servo

Arduino compatible board USB cable

Controller

Breadboard Male-male jumpers Assorted resistors

Push-button Potentiometer LDR (light sensor) Re!ective optical sensor Temperature sensor

Basic parts Output devices

Input devices

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Arduino Uno R3

• Development board with ATmega328 microcontroller and auxliliary circuits

• Client USB interface (device)

• On-board voltage regulator for 7-12V (recommended)

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Arduino: power in

• From USB: 5V

• 7 to 12V DC adapter

• Vin and GND : 7 to 12V DC

5V via USB

7 to 12V DC19

GND, Vin

Arduino: power out

• 3.3 V and 5 V (+)

• GND: ground (-)

• Vin: directly from external supply 7 a 12 V (+)

20Power pins

The word “pin” is often used to refer to holes where pins are connected

Input/output pins14 digital input/output pins: 0...13

6 analog input pins: A0...A5

6 with Pulse Width Modulation:PWM ～

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Inputs × outputs

• Inputs:buttons, knobs, sensors etc.

• Outputs:lights, motors, displays, buzzers etc.

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LEDs 7-segment display 9g micro-servo

Push-button Potentiometer LDR (light sensor) Re!ective optical sensor Temperature sensor

Output devices

Input devices

Breadboard

• Known in Brazil as “protoboard”

• Available in di#erent sizes:

• 830 points

• 400 points

• etc. pictured: 400 points

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Conections inside a regular breadboard

power lines

numbered columns

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25

Note: each part connects to two or

more columns

...or connects one column to a power line

Quiz:can I plug it like this?

live examples by the teacher using the projection screen...

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LED

• Light-emitting diode

• Polarized component: must be connected in the right direction

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LED: light-emitting diode

• + lead (longer) connects to power source

• − lead (shortest) connects to ground

• Connect to resistor in series to protect from excessive current

notch

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LED: basic circuit

Current-limiting resistor according to LED specs

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LED RGB

• 3 LEDs (red, green, blue) in a single component

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Resistors

• Sold in tapes to feed machines in assembly lines

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What is a resistor?

• It reduces current

• No polarity: may be connected either way

• Rated in Ohms (Ω)

• Symbols in schematics:

33

A small detour to understand why

we need resistors

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Voltage, current& resistance

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Feel the power

36Chap. 1, p. 5

Voltage

• Unit: Volt (V)

• Symbol in formulae: V

9 V

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Resistance

• Unit: Ohm (Ω)

• Symbol in formulae: R

7mm of tongue ≈ 330 Ω

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Current

• Unit: Ampère (A)

• Symbol in formulae: I

• 6.241 × 1018 electrons per second

9 V ÷ 330 Ω ≈ 0.027 A27 mA

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Examples of current

Hearing aid 0.7 mA 0.0007 A

Cheap cell phone charger 500 mA 0.5 A

Tablet charger 2.1 A 2.1 A

Toaster (@120V) 16 A 16 A

Automobile starter motor 120 A 120 A

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Ohm’s Law

V = I × R

I = V / R

R = V / IIVR

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Back to the resistor...

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Resistor: color code

33 x 101 = 330 Ω

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Resistor: color code

330Ω with 5% tolerance:from 313Ω to 346Ω

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Resistor: standard values

E12 series of IEC 60063 standard(for 10% tolerance)

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Resistor: examples

330 Ω

1 kΩ

10 kΩ

1 MΩ

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Suitable resistors for LEDs

• In practice, to protect a simple LED in a temporary circuit, a 500 Ω resistor will do

• To determine the ideal resistor for an LED, use Ohm’s Law

(source_voltage − led_voltage_drop)R = led_current

Formula terms

• Source voltage: circuit voltage; for Arduino digital pins that is 5V

• LED voltage drop: voltage drop between LED leads, given as “forward voltage”, “voltage drop” or “forward supply”

• LED current: “forward current”; 20mA is a common value (20/1000 or .02 in formula)

(source_voltage − led_voltage_drop)R = led_current

Example

49

(3 − 2.2)R = = 40 20/1000

LED (green 570nm):fwd. voltage = 2.2Vcurrent = 20mA

RadioShack RGB 5mm LED

• Arduino UNO voltage = 5V

• Red LED voltage drop: 2V

• Red LED current: 50mA

• Ideal resistor: 60Ω

• Real resistor: 68Ω

50

(5 − 2)R = = 60 50/1000

First circuit

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Firstcircuit:blink

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Longer lead (+)

To pin 13

GND pin“ground” (-)

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Firstcircuit:blink

Firstcircuit:blink

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Programming

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Arduino IDE

• Easy to use editor, based on Processing.org, designed for artists

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arduino.cc/en/Main/Software

Language

• C++, simpli"ed

58

Structurecomments

59

Consider the comments in Portuguese a bonus: they

make it easy to tell what is C++ and what is not

comments

60

Structure

variable declaration

comments

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Structure

variable declaration

function definitions

comments

variable declaration

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function definitions

function call

Structure

Logic

63

Arduino runs the setup()

function once after

a reset

Logic

64

The led pin is configured for output

Logic

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Arduino runs the loop()

function over and over, as

fast as it can

Logic

66

digitalWrite changes the state of a digital pin: HIGH is 5V, LOW is 0V

Logic

67

Where would you change the code to control an

LED connected to pin #8?

Logic

68

Where would you change the code to change the

flashing speed?

Syntax

69

instruction blocks are

delimited by ...

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editor highlights

pairs of ..., (...) and [...]

Syntax

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editor colorizes the code to help reading and debugging it

Syntax

C++ syntax tips

• Every statement ends with ; (semicolon)

• Each comma and semicolon counts, but spaces and line breaks are ignored

• Upper case ≠ lower case

• ex. Alpha ≠ alpha ≠ ALPHA

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Coding Dojowith Arduino

Slides at http://bit.ly/dojo-mozilla

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Arduino & co.

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Arduino Family

Nano

Uno Mega

etc...

75Lilypad

The UNO microcontroller:Atmel ATmega328

• “AVR” family

• clock: 16 MHz

• SRAM: 2 KB

• EEPROM: 1 KB

• Flash: 32 KB

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Inputs and outputs of the ATmega328

• 28 pins total

• 23 multi-function pins

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datasheet diagramThis is why the holes in the Arduino connectors are called “pins”: each hole connects to a real pin in the microcontroller.

• Pin functions: standardized and simpli"ed

• Easier to learn

• Easier to design compatible expansions

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Inputs and outputs of the Arduino UNO

Shields

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Arduino with two stacked shields

• Expansion boards

• Some examples:

• Ethernet, Wi-Fi, motor driver, acelerometer, GPS, LCD touch screen...

Shields

80

5stacked shields!

• More examples:

• GPRS, NFC/RFID, MIDI sequencer, MP3 decoder, XBee radio, photocamera controller...

• Don’t miss: shieldlist.org a database with 317 shields from 127 makers

as of March 12, 2014

Clones and derivatives

• Some examples:

• Severino

• Garagino

• Sanguino

• Program-ME

Severino

Vídeo: http://www.youtube.com/watch?v=S4nIV99RMtg82

Arduino clone on breadboard

video: http://www.youtube.com/watch?v=S4nIV99RMtg

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84

Reset button

Voltage regulator

LED connected to “pin 13”

ATMega328

Power-on LED

connects to FTDI adapter for

programmingvia USB

16MHz crystal

More electronic components

85

Potentiometer

• A.k.a: “pot”

• Adjustable resistor

• Symbol in schematics:

86

Potentiometer: how to use

87

Vout

• Connect side leads to source and ground

• Connect central lead Vout to an analog pin on the Arduino

LDR or photoresistor

• Light Dependent Resistor

• Use with resistor to make a voltage divider

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Voltage divider circuit

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Vout

Reading an LDR

• 5V to LDR

• 10k Ω resistor in series, to ground

• between them:Vout connected to an analog pin (ex. A0)

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Tra!c light 1

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Tra!c light 1

• Parts:

• LEDs: green, yellow, red

• 3 suitable resistors

• 1 potentiometer

• Code: gist.github.com/ramalho/6202074

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93

Tra!c light 1

gist.github.com/ramalho/6202074code

(needs fixing)

Tra!c light 1

gist.github.com/ramalho/6202074

gist.github.com/ramalho/6202074

Tra!c light 2

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Tra!c light 2

• Replace the potentiometer with an um LDR (light sensor)

• To make this work, the LDR must be assembled with a resistor to make a voltage divider

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LDR

Tra!c light 2• Parts:

• LEDs: green, yellow, red

• 3 suitable resistors

• 1 potentiometer

• 1 LDR

• 1 resistor for the voltage divider

99

LDR

gist.github.com/ramalho/6202074

same code,

changes needed

Tra!c light 1

Additional components

101

Re)ective optical sensor

• Detects near objects (up to 25mm or 1in)

• Emitter: infrared LED (invisible light)

• Sensor: phototransistor protected against visible light

• Use with voltage divider

bezel

102

voltage divider

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Re)ective optical sensor

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reflective optical sensor

voltage divider

7 segment display

• 3 digits

• model: CPS03631AB

• typo: common anode

• part number: CPS03631BR-11

pictured: CPS3631AR

105

11 digital pins needed to control: 8 for LED segments, 3 to select digit

Schematics from datasheet CPS03631AB

107

anodeanodeanode

7 segment display

7 segment display

• “Common anode” means:all segments of each digit are attached to the same anode

• To select a digit: 5V to the corresponding anode

• To light a segment: GND to the corresponding cathode

108

• Anodes: 5V to pins 8, 9, 12 of the display select the active digit

• GND to other pins light up segments A...G and decimal point (dp)

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7 segment display

gist.github.com/ramalho/6566651code:

7 segment display

Servomotor

• Controlled movement in 180° arch

• Easy programming using Arduino Servolibrary

• examples included with the Arduino IDE

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Servomotor

112

• You may need an external power source just for the servos

External power source GND must connect to Arduino GND

5VDC

Some servos draw more current than the Arduino can provide

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TowerPro SG90 9g servo

to external DC adapter 5V, 1A

common ground

Arduino powered by USB

Wrapping up

114

References

• O!cial Arduino site:arduino.cc

• Arduino Experimentation Kit: oomlout.com/a/products/ardx

• Laboratório de garagemlabdegaragem.com

• Web: blogs, videos, wikis, diagrams...

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arduino.cc

• Seções do site

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Fritzing.org• Fritzing software download and

repository of projects

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Some books

• Arduino Básico, Novatec

• Arduino Cookbook, O’Reilly

• Make: Electronics, O’Reilly

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Physical shops inSão Paulo

• Multcomercial, R. dos Timbiras, 257

• Side streets o# and parallel to Santa E"gênia, including junk stores

• Laboratório de Garagem, Rua Berta, 60 (metrô Vila Mariana)

• Neighborhood shops like Eletrônica Pinheiros, Rua Butantã, 133

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Online shops

• Laboratório de Garagem: labdegaragem.com

• Farnell Newark: farnellnewark.com.br

• Adafruit: adafruit.com

• Sparkfun: sparkfun.com

• Seeedstudio: seeedstudio.com

• Many: dx.com, ebay.com (many sellers)

seeedstudiowith 3 “e”!

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Seeedstudio Shield Bot• Line-following

robot

• Ready to go, only battery assembly is required

• Fits an Arduino UNO under the chassics and shields above

US $ 69.90

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Visit a hackerspace!

garoa.net.br

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Credits

Turing.com.broficinas

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• Slides created, compiled and organized by Luciano Ramalho (O"cinas Turing) with the help of many sources

• License for use and copying:Creative Commons BY-SA

• You may copy and use for any purpose as long as attribution is given and you share derivative works under the same terms