dean brock, rebecca bruce and susan reiser, ccsc se 2009 using arduino material taken from todbot...

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Using ArduinoUsing Arduino

Material taken from Todbot Material taken from Todbot blog Bionic Arduinoblog Bionic Arduino

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

What is the Arduino

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Arduino Duemilanove• 13 digital input/output pins

– Including 6 with PWM for analog output

• 6 analog input pins• USB connection

– For serial I/O and uploading board• ATmega168 or ATmega328 processor

– 16k or 32k for program, 1k or 2k for data

• Arduino bootloader• ~ $30• More Info

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Other Arduino Boards

• Arduino Mega– Lots of I/O pins and lots (128k) of program space

– ~ $65• LilyPad

– For wearable applications– ~ $20

• Boarduino– Fits within a breadboard– ~ $20, but must be soldered!

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 1• Start the Arduino IDE from the terminal window with the command: arduino

• Make sure to connect the PC to the Arduino using the USB cable.

• Designate the connection port and processor type.

• Try out the “blink” example– Select: File > Examples > Digital > Blink

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Connect the USB Cable

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Select Connection and Type

atmega328

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Arduino IDE

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Status Messages

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 1 Modified---Add an External LED to

pin 13• File > Examples > Digital > Blink

• LED’s have polarity – Negative indicated by flat side of the housing and a short leg

www.instructables.com

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Terminology

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Arduino Control

• Very much like Processing/Java– if, then, while, switch– Functions, expressions

• setup()– Runs once at beginning (or reset)

• loop()– Runs continuously

•Like draw()

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Arduino Digital I/O

• pinMode(pin, mode)– Sets pin to either INPUT or OUTPUT

• digitalRead(pin)– Reads HIGH or LOW from a pin

• digitalWrite(pin, value)– Writes HIGH or LOW to a pin

• Electronic stuff you can ignore– Output pins can provide 40 mA of current

– Writing HIGH to an input pin installs a 20KΩ pullup

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Arduino Timing

• delay(ms)– Pauses for a few milliseconds

• delayMicroseconds(us)– Pauses for a few microseconds

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Circuits

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

All holes in each of the four long columns are connected internally.Use these to route power and ground.

Connect this columnto GND (0 volts)

Connect this columnto GND (0 volts)

Connect thiscolumn to 5V

Connect thiscolumn to 5V

There are ten holes that form the rows.These are divided into two sets of five holes.All holes in each set of five are connected

Breadboard Fundamentals

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 2• File > Examples > Digital > Melody

• Speakers have polarity. Positive indicated by small + or dot on piezoelectric speaker.

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 2• Get a breadboard and a piezoelectric speaker

• Assemble as shown

Image credit: Tod Kurt

• Try out the built-in “melody” example– Select: File > Examples > Digital > toneMelody

• Try this version of Melody.pde

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Digital? Analog?• Digital has two values: on and off• Analog has many (infinite) values• Computers don’t really do analog, they quantize

• Remember the 6 analog input pins---here’s how they work

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Analog to Digital• Number of states or “bins” is the resolution

• Arduino resolution is 10-bits (1024 values)

• 5/1024 = 4.8 mV smallest voltage change you can measure

Image credit: Eoin Brazil

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Analog Output

• Computers can’t output analog voltages– Only digital voltages (0 volts or 5 volts)

• Simulating an analog signal with Pulse Width Modulation (PWM)– Can’t directly supply 2.5V, but can pulse the output on and off really fast to produce the same effect---the same effective voltage.

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Analog Output

Vary the effective voltage by modulating the width of the high pulse

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 3• Hardware Needed:

– Resistor (in 220-500 Ohm range)– Breadboard– LED– Wire

• Assemble as shown(MOVE the piezo speaker to pin 7)

–Select: File > Examples > Analog > Fading

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

PWM is Everywhere

• Lamp dimmers, motor, speed control, power supplies, noise making, etc.

• Now on to analog input using sensors---DON’T DISASSEMBLE your breadboards

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Sensing the Dark: Photoresistors

• a.k.a. a photocell or light-dependent resistor

• It is a variable resistor– Brighter light => lower resistance

• Create a voltage divider to use the photoresistor

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 4

• Hardware Needed:– Resistor (approx. 10k Ohm)– Breadboard– Photoresistor– Wire

• Assemble as shown

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

A Theremin• Create a theremin using the photoresistor– A spooky sound machine

•Works by measuring your body’s electric field

– We’ll use light to control the tone produced

• We’ll also control the brightness of the LED using the photoresistor.

• Verify your breadboard configuration!

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Theremin Breadboard Configuration

Hardware Needed: Resistors, Breadboard, Wire, Photoresistor, Piezo speaker, LED

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

The Theremin Program

Load and run the TherminAndLEDprogram

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Sensors

• There are many analog sensors that could be used in place of the photoresistor

• Check out our “theremin” demos created using other sensors

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Communication Between the Arduino and Your

Computer

ArduinoProgram

ProcessingProgram

ArduinoBoard

YourComputer

Serial (TTL)Communication

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Processing• Includes libraries supporting serial communication, video capture, audio processing…

• VERY IMPORTANT: enter the following command in the terminal window to update the serial library:~brock/bin/serialfix

• Start Processing from the terminal window

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 5 • Hardware Needed:

– Resistor (10k Ohm)– Breadboard– Photoresistor– Wire

• Don’t reassemble - this is the same schematic as Activity 4.

Image credit: Tod Kurt

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Activity 5

• Open SimpleWrite.pde into the Arduino IDE.

• Open SimpleRead.pde into Processing.

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Serial Communication in Arduino

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Serial Communication in Processing

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Clarifications

• SimpleWrite spends the first second sampling the photocell readings and setting limits.

• The Arduino program restarts when the Processing program starts.

• If the Processing program begins behaving badly, try pressing the restart button on the Arduino.

Dean Brock, Rebecca Bruce and Susan Reiser, CCSC SE 2009

Project 2

• Project 2