Transcript SAMI Makerspace

Credit to: Sparkfun and Linz Craig, Nick Poole,
Prashanta Aryal, Theo Simpson, Tai Johnson, and
Eli Santistevan
THIS PRESENTATION:
Part One: Hardware
•
Getting around and Arduino
•
Getting connected
•
The breadboard
•
A simple circuit
Part Two: Software
•
The integrated development environment
Part Three: Programming
•
Inputs and outputs
•
Some conventions
•
First Program: Blink
•
Variables
•
Analog versus digital
•
Pulse wave modulation
•
Second Program: Fade
•
Third Program: Button
•
Conditional statements
•
Serial communication
PWR IN
USB
(to Computer)
RESET
SCL\SDA
(I2C Bus)
POWER
5V / 3.3V / GND
Digital I\O
PWM(3, 5, 6, 9, 10, 11)
Analog
INPUTS
PLUG IN YOUR ARDUINO
PROTOTYPING CIRCUITS
SOLDERLESS BREADBOARD
One of the most useful tools in an engineer or
Maker’s toolkit. The three most important
things:
• A breadboard is easier than soldering
• A lot of those little holes are connected, which ones?
• Sometimes breadboards break
WHAT’S A BREADBOARD?
SOLDERLESS BREADBOARD
Each row (horiz.) of 5
holes are connected.
Vertical columns – called
power bus are connected
vertically
USE THE BREADBOARD AND ARDUINO TO BUILT A SIMPLE CIRCUIT
Use the breadboard to
wire up a single LED
with a 330 Ohm
Resistor (OrangeOrange-Brown).
Note: the longer leg on the
LED is the positive leg and
the shorter leg is the
negative
OPEN UP “ARDUINO” APPLICATION
Look for the icon on the desktop of the white clam-shell computers.
You can also download the application for free to your own computers (you may need
to also install the proper drivers)
ARDUINO:
INTEGRATED DEVELOPMENT ENVIRONMENT (IDE)
Two required functions /
methods / routines:
void setup()
{
// runs once
}
void loop()
{
// repeats
}
error & status messages
SETTINGS: TOOLS  SERIAL PORT
Your computer communicates
to the Arduino microcontroller
via a serial port  through a
USB-Serial adapter.
Check to make sure that the
drivers are properly installed.
SETTINGS: TOOLS  BOARD
Next, double-check that the proper board is selected under the
ToolsBoard menu.
CONCEPTS: INPUT VS. OUTPUT
Referenced from the perspective of the microcontroller (electrical board).
Inputs is a signal / information
Output is any signal exiting
going into the board.
the board.
Almost all systems that use physical computing will have some form of output.
What are some examples of Outputs?
CONCEPTS: INPUT VS. OUTPUT
Inputs is a signal / information
Output is any signal exiting the
going into the board.
board.
Examples: Buttons Switches, Light
Sensors, Flex Sensors, Humidity
Sensors, Temperature Sensors…
Examples: LEDs, DC motor, servo
motor, a piezo buzzer, relay, an
RGB LED
YOU DON’T NEED TO SPEAK BINARY!
The Arduino IDE allows you to work in a “high-level programming
language.” The code you write is readable to humans (with a little
training)
The IDE does the hard work of making your code something that
the chip on the Arduino understands:
SUB-ROUTINES/FUNCTIONS/COMMANDS
Arduino uses pre-made sub-routines (small programs) to make your life easier.
Programs like:
• delay()
• if()
• loop()
Can you guess what these do?
Most programs need an input (what they are acting on) and give an output (usually a
numerical value)
The names of these programs (like most things in Arduino) are case sensitive, so type
carefully!
digitalWrite() is not the same as digitalwrite()
pinMode(pin, INPUT/OUTPUT);
ex: pinMode(13, OUTPUT);
digitalWrite(pin, HIGH/LOW);
ex: digitalWrite(13, HIGH);
delay(time_ms);
ex: delay(2500); // delay of 2.5 sec.
// NOTE: -> commands are CASE-sensitive
BIG 6 CONCEPTS
digitalWrite()
analogWrite()
digitalRead()
if() statements / Boolean
analogRead()
Serial communication
SOME CONVENTIONS: CURLY BRACKETS
When you call a sub-routine every thing that happens in the program should be
contained in curly brackets:
Everything between the curly
brackets {..} is part of the loop
function.
SOME CONVENTIONS: SEMICOLONS
Any line of code that isn’t calling a subroutine, or is a sub-routine that is only one
line long should always end with a
semicolon (;)
If you forget these, you will get errors when
you try to “compile” the code!
SOME CONVENTIONS: COMMENTS
It’s easier to get lost in your own
code than you may think.
Leave comments to yourself,
especially before you do
something “tricky.”
They are not needed to make the
program work, but can save you a
lot of trouble in the long run.
PLAN YOUR ATTACK WITH A FLOWCHART
Initialize
Turn LED
ON
Wait
Turn LED
OFF
Wait
1. PUT IN THE “BARE MINIMUM”
The “setup” function runs once and will
lock in any settings you want.
The “loop” function will run for as long as
the Arduino has power!
2. INITIALIZE THE LED PIN AS A “OUTPUT”
Use the “pinMode” command. This
requires two inputs (or arguments). You
must tell it what pin to act on (13 in this
case) and whether that pin is an
OUTPUT or INPUT (this is case
sensitive).
3. TURN ON THE LED FOR ONE SECOND
4. TURN OFF THE LED FOR ONE SECOND
5. REPEAT!
Once the end of the program is reached, it will go to the beginning of loop()
and run it again. And again. And again….
SOME EXTRA CHALLENGES…
•
•
•
•
Make the light blink with a 200 ms interval.
Change the blink to mimic a heart beat.
What’s the fastest blink your eye can detect?
Add two, three, or four LED’s. (each LED will
need its own 330 Ohm resistor).
CONCEPT: VARIABLES
•
•
•
•
•
Declaring variables
Types of variables
Variable scope
Initializing variables
Variable rollover
TYPES OF VARIABLES
8 bits
byte
char
16 bits
int
unsigned int
32 bits
long
unsigned long
float
DECLARING VARIABLES AND SCOPE OF VARIABLES
Variable Scope
Global
Vs.
Function-level
INITIALIZING A VARIABLE: EXAMPLE
Compare this code our early “blink” program.
There is an “int” type variable declared.
• An integer (no decimal)
The variable is named “ledPin”
ledPin is initialized to the value “5”
This is a “global” variable since it was
declared outside of a function.
• All other functions are able to “call” ledPin
and they can change its value
Notice how easy it would be to change
the pin on your circuit that has the LED
connected to it?
CONCEPTS: ANALOG VS. DIGITAL
Microcontrollers are digital devices – ON or OFF. Also called – discrete.
Analog signals are anything that can be a full range of values. What are some examples?
How can we get 3V from a microcontroller that can only be on (5V) or off (0V)?
5V
5V
0V
0V
CONCEPT: PULSE WAVE MODULATION
To create an analog signal, the digital microcontroller uses a
technique called PWM. By varying the duty cycle, we can
mimic an “average” analog voltage.
Pulse Width Modulation (PWM)
PROJECT #2 – FADING
INTRODUCING A NEW COMMAND…
analogWrite(pin, val);
pin – refers to the OUTPUT pin
(limited to pins 3, 5, 6, 9, 10, 11.)
– denoted by a ~ symbol
val – 8 bit value (0 – 255).
0 => 0V
| 255 => 5V
USE AN EXAMPLE PROGRAM
In Arduino, open up:
File  Examples  02.Digital  Button
DIGITAL INPUT: BUTTON
to Digital Pin 2
DIGITAL INPUT: BUTTON
This is just like our 1st circuit!
DIGITAL INPUT
•
Connect digital input to your Arduino using Pins # 0 – 13 (Although pins # 0 & 1
are also used for programming)
•
Digital Input needs a pinMode command:
pinMode (pinNumber, INPUT);
Make sure to use ALL CAPS for INPUT
•
To get a digital reading:
int buttonState = digitalRead (pinNumber);
•
Digital Input values are only HIGH (On) or LOW (Off)
DIGITAL SENSORS
• Digital sensors are more straight forward than Analog
• No matter what the sensor there are only two settings:
On and Off
• Signal is always either HIGH (On) or LOW (Off)
• Voltage signal for HIGH will be a little less than 5V on
your Uno
• Voltage signal for LOW will be 0V on most systems
CONDITIONAL STATEMENTS: IF()
CONDITIONAL STATEMENTS: IF()
void loop()
{
int buttonState = digitalRead(5);
if(buttonState == LOW)
{
// do something
}
else
{
}
}
// do something else
DIG
INPUT
BOOLEAN OPERATORS
<Boolean>
(
(
(
(
(
(
)
)
)
)
)
)
==
!=
>
>=
<
<=
(
(
(
(
(
(
)
)
)
)
)
)
Description
is equal?
is not equal?
greater than
greater than or equal
less than
less than or equal
USING SERIAL COMMUNICATION
Method used to transfer data between two devices.
Data passes between the computer and Arduino
through the USB cable. Data is transmitted as a string
of zeros (‘0’) and ones (‘1’).
Arduino dedicates Digital I/O pin # 0 to
receiving and Digital I/O pin #1 to transmit.
SERIAL MONITOR & ANALOGREAD()
Initializes the Serial
Communication
9600 baud data rate
prints data to serial bus
SERIAL MONITOR & ANALOGREAD()
Opens up a Serial
Terminal Window
EXAMPLE
void loop ( )
{
Serial.print(“Hands on “) ;
Serial.print(“Learning ”) ;
Serial.println(“is Fun!!!”) ;
}
Serial.print adds to the same line.
Serial.println adds to the line, then
“returns” (starts a new line).
USING SERIAL COMMUNICATION TO DEBUG
AND TROUBLESHOOT
Let’s use serial communication to watch what is happening in
our “button” program.