Transcript EGN-1002-Arduino

What is Arduino?
Arduino is an open-source electronics prototyping platform
based on flexible, easy-to-use hardware and software.
Arduino can be used to develop stand-alone interactive
objects or can be connected to software on your computer.
It's intended for artists, designers, hobbyists, and anyone
interested in creating interactive objects or environments.
Arduino web site: www.arduino.cc
Instructor: Dr. Yu.Vlasov
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Instructor: Dr. Yu.Vlasov
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Adruino boards
Arduino
Arduino BT
Arduino MINI
Arduino NANO
LilyPad Arduino
Ethernet shield
Xbee shield
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(Not to scale)
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Arduino Duemilanove Microcontroller
("Duemilanove" means 2009 in Italian)
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Arduino Board Overview
USB chip
Digital input/output pins
USB connector
Power LED
Reset button
Microcontroller
chip
Power connector
Power
pins
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Analog
Input
pins
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Arduino Board Schematic
Instructor: Dr. Yu.Vlasov
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Arduino Duemilanove Microcontroller Board
Duemilanove - the latest revision (2009) of the basic Arduino USB
board. It connects to the computer with a standard USB cable and
contains everything else you need to program and use the board. It
can be extended with a variety of shields: custom daughter-boards
with specific features.
It has:
• 14 digital input/output pins (of which 6 can be used as PWM (Pulse
Width Modulation) outputs)
•
•
•
•
•
•
6 analog inputs
a 16 MHz crystal oscillator
a USB connection
a power jack
an ICSP (In-Circuit Serial Programming) header
a reset button.
Instructor: Dr. Yu.Vlasov
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Digital or Analog?
• Digital – may take two values only: ON or OFF (1 or 0)
• Analog – has many (infinite) values
Computers don’t really do analog -- so they fake it, with quantization
Instructor: Dr. Yu.Vlasov
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Arduino Duemilanove Microcontroller Board
Power:
The Arduino Duemilanove can be powered via the USB connection or
with an external power supply. The power source is selected
automatically.
External (non-USB) power can come either from an AC-to-DC
adapter (wall-wart) or battery. The adapter can be connected by
plugging a 2.1 mm center-positive plug into the board's power jack.
Leads from a battery can be inserted in the Gnd and Vin pin headers
of the POWER connector.
The board can operate on an external supply of 6 to 20 volts. If
supplied with less than 7 V, however, the 5 V pin may supply less
than five volts and the board may be unstable. If using more than 12
V, the voltage regulator may overheat and damage the board.
The recommended range is 7 to 12 volts.
Instructor: Dr. Yu.Vlasov
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Arduino Duemilanove Microcontroller Board
The power pins are as follows:
• Vin. The input voltage to the Arduino board when it's using an external power source (as
opposed to 5 volts from the USB connection or other regulated power source). You can
supply voltage through this pin, or, if supplying voltage via the power jack, access it
through this pin.
• 5V. The regulated power supply used to power the microcontroller and other components
on the board. This can come either from Vin via an on-board regulator, or be supplied by
USB or another regulated 5V supply.
• 3V3. A 3.3 volt supply generated by the on-board FTDI chip. Maximum current draw is 50
mA.
• GND. Ground pins.
USB connector
Power connector
3V3 output
Instructor: Dr. Yu.Vlasov
5V output
Vin
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Arduino Duemilanove Microcontroller Board
The Duemilanove basic board uses the Atmel ATmega328 chip
(http://www.atmel.com/dyn/resources/prod_documents/8161S.pdf).
Microcontroller
Operating Voltage
Input Voltage
(recommended)
Input Voltage (limits)
ATmega328
5V
Digital I/O Pins
14 (of which 6 provide PWM output)
Analog Input Pins
DC Current per I/O Pin
DC Current for 3.3V Pin
6
40 mA
50 mA
Flash Memory
32 KB (ATmega328) of which 2 KB used by bootloader
SRAM
2 KB (ATmega328)
EEPROM
1 KB (ATmega328)
Clock Speed
16 MHz
Instructor: Dr. Yu.Vlasov
7-12 V
6-20 V
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Using the breadboard
(Socket board)
The bread board has many strips of metal
(copper usually) which run underneath the
board.
The metal strips are laid out as shown in
orange. The long top and bottom row of
holes are usually used for power supply
connections.
To use the bread board, the legs
of components are placed in the
holes (the sockets). The holes
are made so that they will hold
the component in place. The
circuit is built by placing
components and connecting them
together with jumper wires.
Instructor: Dr. Yu.Vlasov
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What do you need to start working
with Arduino?
1. Arduino board – will be provided
2. USB cable – will be provided
3. Computer with USB interface
4. USB driver and Arduino application – to be
downloaded from (http://arduino.cc/en/Main/Software)
Instructor: Dr. Yu.Vlasov
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Download the Arduino environment
To program the Arduino board you need the Arduino
environment.
Download the latest version from the page:
http://arduino.cc/en/Main/Software
When the download finishes, unzip the downloaded file.
Make sure to preserve the folder structure. Double-click
the folder to open it. There should be a few files and subfolders inside.
Doubleclick
Instructor: Dr. Yu.Vlasov
-- it will start Arduino software
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Download USB drivers
To connect your Arduino board to computer you need
USB drivers for the FTDI chip on the board.
You'll want to install the USB drivers before plugging in
the Arduino for the first time.
Download the latest version from the page:
http://www.ftdichip.com/Drivers/VCP.htm
(You can download executable file http://www.ftdichip.com/Drivers/CDM/CDM%202.04.16.exe
running which will install drivers)
Install the drivers.
Instructor: Dr. Yu.Vlasov
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Arduino software
UPLOAD BUTTON
INPUT AREA
STATUS BAR
PROGRAM NOTIFICATION AREA
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Arduino software
Select your port
Instructor: Dr. Yu.Vlasov
Select microcontroller type
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Power up! (USB)
Now we are ready for the moment of truth, it's time to plug your
Arduino in and power it up. The most common way to do this is to
plug one end of the USB cable into the Arduino and the other end
into a computer. The computer will then power the Arduino.
Plug the square end of USB
cable into your Arduino; the
other end – into computer.
Instructor: Dr. Yu.Vlasov
You should get a small green
light on the right side of the
Arduino, as shown here
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Example 01
Your first program:
/*
* “Hello World!”
* This is the Hello World! for Arduino.
* It shows how to send data to the computer
*/
void setup()
{
Serial.begin(9600);
// run once, when the sketch starts
// set up Serial library at 9600 bps
Serial.println("Is anybody out there?");
break
}
void loop()
{
// prints phrase with ending line
// run over and over again
// do nothing!
}
// After sending program to the Arduino, press Reset button on the board and
watch Serial monitor
Run this program. What do you see on the Serial Monitor?
Instructor: Dr. Yu.Vlasov
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Arduino Program (Sketch) Structure
Declare variables at top
• Initialize
• setup() – run once at beginning, set pins
• Running
• loop() – run repeatedly, after setup()
Example of a bare minimum program:
void setup()
{
}
void loop()
{
}
Instructor: Dr. Yu.Vlasov
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Arduino “Language”
• Language is standard C/C++ (but made easy)
• Lots of useful functions
pinMode() – set a pin as input or output
digitalWrite() – set a digital pin high/low
digitalRead() – read a digital pin’s state
analogRead() – read an analog pin
analogWrite() – write an “analog” PWM value
delay() – wait an amount of time (ms)
millis() – get the current time
• And many others. And libraries. And examples!
Instructor: Dr. Yu.Vlasov
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Format of variables – 01
All variables have to be declared before they are
used.
Declaring a variable means defining its type, and
optionally, setting an initial value (initializing the
variable).
For example,
int inputVariable = 0;
declares that variable inputVariable is of type
int, and that its initial value is zero.
Instructor: Dr. Yu.Vlasov
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Format of variables – 02
1. char – a data type that takes up 1 byte of memory that
stores a character value. Character literals are written in
single quotes, like this: 'A'.
2. byte – a byte stores an 8-bit unsigned number, from 0
to 255.
3. int – integers are your primary datatype for number
storage, and store a 2 byte value. This yields a range of
−32,768 to 32,767.
4. unsigned int – unsigned integers are the same as
integers in that they store a 2 byte value. Instead of
storing negative numbers however they only store
positive values, yielding a useful range of 0 to 65,535.
Instructor: Dr. Yu.Vlasov
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Format of variables – 03
5. long – long variables are extended size variables for
number storage, and store 32 bits (4 bytes), from
−2,147,483,648 to 2,147,483,647.
6. unsigned long – unsigned long variables are extended
size variables for number storage, and store 32 bits (4
bytes). Unlike standard longs unsigned longs won't store
negative numbers, making their range from 0 to
4,294,967,295
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Format of variables – 04
7. float – datatype for floating-point numbers, a number
that has a decimal point. They are often used to
approximate analog and continuous values because they
have greater resolution than integers. Floating-point
numbers can be as large as 3.4028235E+38 and as low
as −3.4028235E+38. They are stored as 32 bits (4 bytes)
of information.
8. double – double precision floating point number.
Occupies 4 bytes. The double implementation on the
Arduino is currently exactly the same as the float, with
no gain in precision.
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Format of variables – 05
Example of variables:
char myChar = 'A';
char myChar = 65; // both are equivalent
byte b = B10010;
// "B" is the binary
formatter (B10010 = 18
decimal)
int ledPin = 13;
unsigned int ledPin = 13;
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Arithmetic Operators
Arithmetic operators include addition, subtraction,
multiplication, and division. They return the sum,
difference, product, or quotient of two operands.
y
x
i
r
Instructor: Dr. Yu.Vlasov
=
=
=
=
y
x
j
r
+
*
/
3;
7;
6;
5;
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Example 02
Math
/* Math */
int a = 5;
int b = 10;
int c = 20;
Run this program.
void setup()
{
Serial.begin(9600); // set up Serial library at 9600 bps
What do you see on the
Serial Monitor?
Serial.println("Here is some math: ");
Replace format “int” with
“float”
Serial.print("a = ");
Serial.println(a);
Serial.print("b = ");
Serial.println(b);
Serial.print("c = ");
Serial.println(c);
Serial.print("a + b = ");
Serial.println(a + b);
// add
Serial.print("a * c = ");
Serial.println(a * c);
// multiply
Serial.print("c / b = ");
Serial.println(c / b);
// divide
Serial.print("b - c = ");
Serial.println(b - c);
// subtract
Run this program again.
What do you see on the
Serial Monitor?
}
void loop() // we need this to be here even though its empty
{
}
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Compound Operators
Increment or decrement a variable
X
X
X
X
X
X
++
-+=
-=
*=
/=
y
y
y
y
//
//
//
//
//
//
same
same
same
same
same
same
as
as
as
as
as
as
x
x
x
x
x
x
//
//
//
//
//
= 2
now
now
now
now
=
=
=
=
=
=
x
x
x
x
x
x
+
–
+
*
/
1,
1,
y,
y,
y,
y,
or
or
or
or
or
or
increments x
decrements x
increments x
decrements x
multiplies x
divides x by
by
by
by
by
by
y
+1
-1
+y
-y
y
Example:
x
x
x
x
x
= 2;
+= 4;
-= 3;
*= 10;
/= 2;
Instructor: Dr. Yu.Vlasov
x
x
x
x
x
contains
contains
contains
contains
6
3
30
15
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Comparison operators
x
x
x
x
x
x
Instructor: Dr. Yu.Vlasov
==
!=
<
>
<=
>=
y
y
y
y
y
y
(x
(x
(x
(x
(x
(x
is
is
is
is
is
is
equal to y)
not equal to
less than y)
greater than
less than or
greater than
y)
y)
equal to y)
or equal to y)
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“if” condition
“if”, which is used in conjunction with a comparison operator,
tests whether a certain condition has been reached, such as an
input being above a certain number. The format for an “if” test
is:
if (someVariable > 50)
{
// do something here
}
comparison operator
The program tests to see if someVariable is greater than 50. If it
is, the program takes a particular action.
If the statement in parentheses is true, the statements inside the
brackets are run. If not, the program skips over the code.
Example:
if (x > 120) digitalWrite(LEDpin, HIGH);
Instructor: Dr. Yu.Vlasov
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“if…else”
The “if-else” is the primary means of conditional branching.
To branch an execution of your program depending on the state of a
digital input, we can use the following structure:
if (inputPin
== HIGH)
{
doThingA;
}
else
{
doThingB;
}
Instructor: Dr. Yu.Vlasov
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“for” statement
The “for” statement is used to repeat a block of statements
enclosed in curly braces. An increment counter is usually used to
increment and terminate the loop. The “for” statement is useful
for any repetitive operation:
for (initialization; condition; increment)
{
//statement(s);
}
The “initialization” happens first and exactly once. Each
time through the loop, the “condition” is tested; if it's true, the
“statement” block, and the “increment” is executed, then the
“condition” is tested again. When the “condition” becomes
false, the loop ends.
Example:
if (x > 120) digitalWrite(LEDpin, HIGH);
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“for” statement
Example “Dim an LED using a PWM pin”:
int PWMpin = 10; // LED in series with 1k resistor on pin 10
void setup()
{
// no setup needed
}
initialization
void loop()
{
for (int i=0; i <= 255; i++)
{
analogWrite(PWMpin, i);
delay(10);
}
}
Instructor: Dr. Yu.Vlasov
condition
increment
statement
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“switch ... case”
switch...case controls the flow of programs by allowing
programmers to specify different code that should be executed in
various conditions.
When a case statement is found whose value matches that of the
variable, the code in that case statement is run.
Example:
Instructor: Dr. Yu.Vlasov
switch (var)
{
case label:
// statements
break;
case label:
// statements
break;
default:
// statements
}
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“while” loop
while loops will loop continuously, and infinitely, until the
expression inside the parenthesis, () becomes false. Something
must change the tested variable, or the while loop will never exit.
This could be in your code, such as an incremented variable, or
an external condition, such as testing a sensor.
while(someVariable ?? value)
{
doSomething;
}
Example:
const int button2Pin = 2;
buttonState = LOW;
while(buttonState == LOW)
{
buttonState = digitalRead(button2Pin);
}
Instructor: Dr. Yu.Vlasov
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“do … while” loop
The “do” loop works in the same manner as the “while” loop,
with the exception that the condition is tested at the end of the
loop, so the “do” loop will always run at least once.
do
{
doSomething;
}
while (someVariable ?? value);
Example:
do
{
x = readSensor();
delay(10);
}
while (x < 100);
Instructor: Dr. Yu.Vlasov
// loops if x < 100
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Connection
“+” (long) lead of LED should
be connected to Pin #13.
The other (short) lead of the
LED goes to “Ground”
Instructor: Dr. Yu.Vlasov
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Example 03a
/* Blink
Turns an LED ON and OFF repeatedly.
There is already an LED on the board
*/
int ledPin =
13;
Red LED
connected to pin 13.
// LED connected to digital pin 13
void setup()
{
pinMode(ledPin, OUTPUT); // initialize the digital pin as an output
}
void loop()
{
digitalWrite(ledPin, HIGH);
delay(1000);
digitalWrite(ledPin, LOW);
delay(1000);
}
Instructor: Dr. Yu.Vlasov
//
//
//
//
set the LED on
wait for a second
set the LED off
wait for a second
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Example 03b
/* Blink
Turns an LED ON and OFF repeatedly.
There is already an LED on the board
*/
int ledPin = 13;
int ON = 100;
int OFF = 100;
Blinking LED
connected to pin 13.
// LED connected to digital pin 13
// (ms) time for LED to be ON
// (ms) time for LED to be OFF
void setup()
{
pinMode(ledPin, OUTPUT); // initialize the digital pin as an output
}
void loop()
{
digitalWrite(ledPin, HIGH);
delay(ON);
digitalWrite(ledPin, LOW);
delay(OFF);
}
//
//
//
//
set the LED on
wait for a second
set the LED off
wait for a second
Play with values of constants “ON” and “OFF”
Instructor: Dr. Yu.Vlasov
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Example 03c
Blinking LED
/* Blink without Delay
Turns on and off a light emitting diode(LED) connected to a digital pin, without using the
delay() function. This means that other code can run at the same time without being
interrupted by the LED code.
The circuit: LED attached from pin 13 to ground. */
const int ledPin =
13;
// the number of the LED pin. Constants won't change.
int ledState = LOW;
long previousMillis = 0;
long interval = 1000;
// ledState used to set the LED. Variables will change
// will store last time LED was updated. Variables will change
// interval at which to blink (milliseconds)
void setup() {
pinMode(ledPin, OUTPUT);
}
// set the digital pin as output:
void loop()
{
// check to see if it's time to blink the LED; that is, is the difference between the
current time and last time we blinked the LED bigger than the interval at which we want to
blink the LED.
if (millis() - previousMillis > interval)
{
previousMillis = millis();
// save the last time you blinked the LED
if (ledState == LOW) ledState = HIGH;
else ledState = LOW;
digitalWrite(ledPin, ledState);
// set the LED with the ledState of the variable
}
}
Instructor: Dr. Yu.Vlasov
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Connection
3 LEDs connected from digital pins 9, 10, 11 to ground through
220 ohm resistors
LED
220 Ohm
220 Ohm
220 Ohm
Instructor: Dr. Yu.Vlasov
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Example 04
3 LEDs
/* The circuit: 3 LEDs connected from digital pins 9,10,11 to ground through 220
ohm resistors. */
int
int
int
int
int
led9Pin = 9;
led10Pin = 10;
led11Pin = 11;
ON = 1000;
OFF = 1000;
// LED 9 connected to digital pin 9
// LED 10 connected to digital pin 10
// LED 11 connected to digital pin 11
// (ms) time for LED to be ON
// (ms) time for LED to be OFF
void setup()
// initialize digital pins as an output:
{
pinMode(led9Pin, OUTPUT);
pinMode(led10Pin, OUTPUT);
pinMode(led11Pin, OUTPUT);
}
void loop()
{
digitalWrite(led9Pin, HIGH);
delay(ON);
digitalWrite(led9Pin, LOW);
delay(OFF);
//
//
//
//
set the LED on
wait for time “ON” (ms)
set the LED off
wait for time “OFF” (ms)
digitalWrite(led10Pin, HIGH); delay(ON); digitalWrite(led10Pin, LOW); delay(OFF);
digitalWrite(led11Pin, HIGH); delay(ON); digitalWrite(led11Pin, LOW); delay(OFF);
}
Instructor: Dr. Yu.Vlasov
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Connection
220 Ohm
15 KOhm
LED on pin #13 is operated by a button on pin #2
Push
button
+5V
Instructor: Dr. Yu.Vlasov
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Example 05
/* LED on pin #13 is operated by a button on pin #2
const int led13Pin = 13;
const int button2Pin = 2;
int buttonState = 0;
Button
*/
// variable for reading the pushbutton status
void setup()
{
pinMode(led13Pin, OUTPUT);
pinMode(button2Pin, INPUT);
}
void loop()
{
buttonState = digitalRead(button2Pin);
if (buttonState == HIGH)
{
digitalWrite(led13Pin, LOW);
}
else
{
digitalWrite(led13Pin, HIGH);
}
}
Instructor: Dr. Yu.Vlasov
45
Connection
Three LEDs on pins 9, 10, 11 are controlled by a button on pin 2
220 Ohm
220 Ohm
220 Ohm
220 Ohm
15 KOhm
LED
Push
button
+5V
Instructor: Dr. Yu.Vlasov
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Example 06
/* LEDs on pins 9,10,11 are controlled by a button on pin #2
const int led7Pin = 9;
const int led10Pin = 10;
const int led11Pin = 11;
const int led13Pin = 13;
const int ON = 100;
const int OFF = 10;
const int button2Pin = 2;
int buttonState = 0;
Button
*/
// LED 9 connected to digital pin 9
// LED 10 connected to digital pin 10
// LED 11 connected to digital pin 11
// (ms) time for LED to be ON
// (ms) time for LED to be OFF
void setup()
{
// initialize digital pins
pinMode(led9Pin, OUTPUT);
pinMode(led10Pin, OUTPUT);
pinMode(led11Pin, OUTPUT);
pinMode(led13Pin, OUTPUT);
pinMode(button2Pin, INPUT);
}
void loop()
{
buttonState = digitalRead(button2Pin);
if (buttonState == HIGH)
{
digitalWrite(led13Pin, LOW);
digitalWrite(led9Pin, HIGH);
delay(ON);
digitalWrite(led9Pin, LOW);
delay(OFF);
//
//
//
//
set the LED on
wait for a second
set the LED off
wait for a second
digitalWrite(ed10Pin, HIGH);
delay(ON);
digitalWrite(ed10Pin, LOW);
delay(OFF);
//
//
//
//
set the LED on
wait for a second
set the LED off
wait for a second
digitalWrite(led11Pin, HIGH);
delay(ON);
digitalWrite(led11Pin, LOW);
delay(OFF);
//
//
//
//
set the LED on
wait for a second
set the LED off
wait for a second
}
else
{
digitalWrite(led13Pin, HIGH);
}
}
Instructor: Dr. Yu.Vlasov
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analogWrite()
Writes an analog value (PWM wave) to a pin.
Can be used to light a LED at varying brightnesses or
drive a motor at various speeds.
After a call to analogWrite(), the pin will generate
a steady square wave of the specified duty cycle until the
next call to analogWrite() (or a call to
digitalRead() or digitalWrite() on the same
pin).
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48
analogWrite()
The frequency of the PWM signal is approximately 490
Hz.
On Arduino Duemilanove boards this function works on
pins 3, 5, 6, 9, 10, and 11 (marked with “PWM”.)
analogWrite(pin, value)
Where:
pin: the pin to write to.
value: the duty cycle: between 0 (always off) and 255
(always on).
Instructor: Dr. Yu.Vlasov
49
Example 07a
PWM. LED fading
/* Fading
This example shows how to fade an LED using the analogWrite() function.
The circuit: LED attached from digital pin 9 to ground.
*/
int ledPin = 9;
// LED connected to digital pin 9
void setup()
{
// nothing happens in setup
}
void loop()
{
for(int fadeValue = 0 ; fadeValue <= 255; fadeValue++) // fade in from min to max in
increments
{
analogWrite(ledPin, fadeValue); // sets the value (range from 0 to 255)
delay(2); // wait for x milliseconds to see the dimming effect
}
for(int fadeValue = 255 ; fadeValue >= 0; fadeValue--) // fade out from max to min in
increments
{
analogWrite(ledPin, fadeValue); // sets the value (range from 0 to 255)
delay(2); // wait for x milliseconds to see the dimming effect
}
}
Instructor: Dr. Yu.Vlasov
50
Connection
LEDs on pins 9 is controlled by a potentiometer
220 Ohm
220 Ohm
220 Ohm
220 Ohm
15 KOhm
LED
Push
button
+5V
+5V
Instructor: Dr. Yu.Vlasov
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Example 07b
PWM. LED fading
/*
LEDs on pins 9 is controlled by a potentiometer
Demonstrates one techinque for calibrating sensor input. The sensor readings during the first five seconds of the sketch execution define
the minimum and maximum of expected values attached to the sensor pin.
The sensor minumum and maximum initial values may seem backwards. Initially, you set the minimum high and listen for anything lower,
saving it as the new minumum. Likewise, you set the maximum low and listen for anything higher as the new maximum.
The circuit:
* Potentiometer (or analog sensor) is attached to analog input 0
* LED attached from digital pin 9 to ground
*/
const int sensorPin = 1;
const int ledPin = 9;
// pin that the sensor is attached to
// pin that the LED is attached to
int sensorValue = 0;
int sensorMin = 1023;
int sensorMax = 0;
// the sensor value
// minimum sensor value
// maximum sensor value
void setup() {
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
// turn on LED to signal the start of the calibration period:
while (millis() < 5000) {
// calibrate during the first five seconds
sensorValue = analogRead(sensorPin);
if (sensorValue > sensorMax) {
sensorMax = sensorValue;
}
// record the maximum sensor value
if (sensorValue < sensorMin) {
sensorMin = sensorValue;
}
// record the minimum sensor value
}
digitalWrite(13, LOW);
// signal the end of the calibration period
}
void loop() {
sensorValue = analogRead(sensorPin);
// read the sensor:
sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 255);
// apply the calibration to the sensor reading
sensorValue = constrain(sensorValue, 0, 255); // in case the sensor value is outside the range seen during calibration
analogWrite(ledPin, sensorValue);
// fade the LED using the calibrated value:
}
Instructor: Dr. Yu.Vlasov
52
Connection
Ping Sensor is connected: +V is attached to +5V
PING
GND is attached to ground
SIG is attached to digital pin 4
SIG
GND
+5V
220 Ohm
220 Ohm
220 Ohm
220 Ohm
15 KOhm
LED
Push
button
+5V
Instructor: Dr. Yu.Vlasov
53
Example 08
PING sensor
/* Ping Sensor
This sketch reads a PING))) ultrasonic rangefinder and returns the
distance to the closest object in range. To do this, it sends a pulse
to the sensor to initiate a reading, then listens for a pulse
to return. The length of the returning pulse is proportional to
the distance of the object from the sensor.
The circuit:
* +V connection of the PING))) attached to +5V
* GND connection of the PING))) attached to ground
* SIG connection of the PING))) attached to digital pin 4
*/
const int pingPin = 4;
void setup()
{
Serial.begin(9600);
}
// pin number of the sensor's output:
// initialize serial communication
void loop()
{
// establish variables for duration of the ping,
// and the distance result in inches and centimeters:
long duration, inches, cm;
// The PING is triggered by a HIGH pulse of 2 or more microseconds.
// Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
// The same pin is used to read the signal from the PING))): a HIGH
// pulse whose duration is the time (in microseconds) from the sending
// of the ping to the reception of its echo off of an object.
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH); // Reads a pulse (either HIGH or LOW) on a pin.
Instructor: Dr. Yu.Vlasov
54
Example 08
PING sensor
(continued)
// convert the time into a distance
inches = microsecondsToInches(duration);
cm = microsecondsToCentimeters(duration);
Serial.print(inches);
Serial.print("in, ");
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(100);
}
long microsecondsToInches(long microseconds)
{
// According to Parallax's datasheet for the PING))), there are
// 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
// second). This gives the distance travelled by the ping, outbound
// and return, so we divide by 2 to get the distance of the obstacle.
// See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
return microseconds / 74 / 2;
}
long microsecondsToCentimeters(long microseconds)
{
// The speed of sound is 340 m/s or 29 microseconds per centimeter.
// The ping travels out and back, so to find the distance of the
// object we take half of the distance travelled.
return microseconds / 29 / 2;
}
Instructor: Dr. Yu.Vlasov
55
Connection
Temperature sensor LM35DZ
+5V
Instructor: Dr. Yu.Vlasov
56
Example 09
LM35DZ temperature sensor
// LM35DZ Temperature Sensor for Arduino.
// (cc) by Daniel Spillere Andrade , http://www.danielandrade.net
int
int
int
int
int
pin = 0;
tempc = 0,tempf=0;
samples[8];
maxi = -100,mini = 100;
i;
void setup()
{
Serial.begin(9600);
}
//
//
//
//
analog input pin
temperature variables
variables to make a better precision
to start max/min temperature
// start serial communication
void loop()
{
for(i = 0; i<=7; i++)
{ // gets 8 samples of temperature
samples[i] = ( 5.0 * analogRead(pin) * 100.0) / 1024.0;
tempc = tempc + samples[i];
delay(10);
}
tempc = tempc/8;
// better precision
tempf = (tempc * 9)/ 5 + 32;
// converts to fahrenheit
if(tempc > maxi) {maxi = tempc;} // set max temperature
if(tempc < mini) {mini = tempc;} // set min temperature
Serial.print(tempc,DEC);
Serial.print(" Celsius, ");
Serial.print(tempf,DEC);
Serial.print(" fahrenheit -> ");
Serial.print(maxi,DEC);
Serial.print(" Max, ");
Serial.print(mini,DEC);
Serial.println(" Min");
tempc = 0;
delay(1000);
// delay before loop
}
Instructor: Dr. Yu.Vlasov
57
Connection
Sharp LM35DZ IR light detector and IR LED
Sharp
IS471FE
4
3
2
1
+5V
IR
LED
Instructor: Dr. Yu.Vlasov
58
Example 10
/* Sharp
Circuit:
Leg 1 is
Leg 2 is
Leg 3 is
Leg 4 is
Positive
*/
Sharp IS471FE IR sensor
LM35DZ IR light detector with built-in signal processing sircuit for light modulation
connected to Vcc (+5V)
connected to digital pin 6
connected to ground
connected to negative terminal of IR LED
terminal of IR LED is connected to Vcc (+5V)
const int IR_SENSOR_PIN = 6;
const int ledPin = 13;
int IR_SENSOR_STATE = 0;
void setup()
{
pinMode(IR_SENSOR_PIN, INPUT);
Serial.begin(9600);
}
void loop()
{
IR_SENSOR_STATE = digitalRead(IR_SENSOR_PIN);
if (IR_SENSOR_STATE == LOW)
{
Serial.println("No object");
digitalWrite(ledPin, LOW);
}
else
{
Serial.println("Object detected");
digitalWrite(ledPin, HIGH);
}
delay(100);
}
Instructor: Dr. Yu.Vlasov
59
Pseudo Code
• Start of program
• Measure temperature
- Is temperature < 100 F ?
• Yes, Turn on heat
- Is temperature > 102 F ?
• Yes, Turn on cooling fan
• Go back to start.
Instructor: Dr. Yu.Vlasov
60
Flow Chart
Start
Measure
Temperature
Temp.
< 100
Yes
Energize
Heater
No
Temp.
> 102
Yes
Energize
Fan
No
Instructor: Dr. Yu.Vlasov
61
Sequential Flow Example
Instructor: Dr. Yu.Vlasov
Pseudo-Code:
Flowchart:
Start of program
Start

Turn off LED 1
Turn OFF LED1

Turn off LED 2
Turn OFF LED2

Pause for 2 seconds
2 Second Pause

Light LED 1

Pause for 2 seconds

Light LED 2

End of program
Turn ON LED1
2 Second Pause
Turn ON LED2
End
62
Looping Flow Example
Pseudo-Code:
Start of program
Instructor: Dr. Yu.Vlasov
Flowchart:
Start

Turn off LED 1
Turn OFF LED1

Turn off LED 2
Turn OFF LED2

Pause for 2 seconds
2 Second Pause

Light LED 1

Pause for 2 seconds

Light LED 2

Go back to start
Turn ON LED1
2 Second Pause
Turn ON LED2
63
“IF-THEN” Example: Alarm
This program will sound the alarm as long as pushbutton 1 is pressed.
Pseudo-Code
Start:
Is button 1 pressed?
• Yes, Go sound Alarm
• No, Go back to start
Alarm:
• Sound speaker
• Go back to start of program
Flowchart
Main
False
Button 1
Pressed
True
Speaker
2000Hz for
1 second
Main
Instructor: Dr. Yu.Vlasov
64
References
1. http://www.arduino.cc/en/Tutorial/HomePage
2. http://www.arduino.cc/en/Guide/HomePage
3. http://www.ladyada.net/learn/arduino/index.html -- an introduction to programming,
input / output, communication, etc. using Arduino
4. http://arduino.cc/en/Reference/HomePage -- Programming Language Reference
5. http://todbot.com/blog/spookyarduino/
6. http://dma.ucla.edu/senselab/topics/tags/arduino
7. http://www.freeduino.org/
8. http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl -- Arduino forum
Instructor: Dr. Yu.Vlasov
65
Connection
PING
220 Ohm
220 Ohm
220 Ohm
GND
220 Ohm
15 KOhm
LED
SIG
Push
button
+5V
+5V
Instructor: Dr. Yu.Vlasov
66