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Arduino An Introduction to Engineers
Hong Zhang, PhD
Mechanical Engineering
Rowan University
What is Arduino
• Arduino is an open-source electronics prototyping
platform based on flexible, easy-to-use hardware
and software.
Peripherals
USB Cord
Battery Wires
Breadboard
Wire Stripper
Amazon Kit
Sparkfun Kit
Soldering
Solder
Stand
Perfboard Long nose plier
Solder Remover Iron
Variations
LilyPad
Mini Esplora
Due
Shields
Touchpad Joystick
Cellphone LCD TinkerKit
Clones
Motoruino
Maple Boarduino
Roboduino Freeduino
Sanguino
USB Jack
Transmission status LED
Pin 13 LED
Power Jack
Reset
Microcontroller ATMEGA328
Power Pins Analog Input Pins
Digital I/O Pins
ICSP Header
Power LED
Voltage Regulator
USB Chip
Crystal
Verify the grammar
Upload to the Arduino board
New file
Open a file
Save the current file
Open up the serial monitor window
Code
Message Serial port
Use Arduino
Generate Idea
Make Plans
Write Code
Upload & Test
Design Circuit
Review, rebuild, modification
Project Goal
• Don’t put Arduino board on metal surface!
• Unplug power first before making any change on
circuit.
• If you smell something, see smoke or flame, touch
something burning, then something must be wrong!
Disconnect the power first.
1 Safety
Get Started
• http://arduino.cc/en/Main/Software
Learn From Examples • Online:
http://arduino.cc/en/Tutorial/HomePage
• Or from local Examples
Blink Example /*
Blink
Turns on an LED on for one second, then off for one second,
repeatedly.
This example code is in the public domain.
*/
void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(13, OUTPUT);
}
void loop() {
digitalWrite(13, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(13, LOW); // set the LED off
delay(1000); // wait for a second
}
pinMode(pin#, OUTPUT) • The specified pin can provide a substantial amount
of current to other circuits.
• Current is up to 40 mA (milliamps) to other
devices/circuits.
• Enough for an LED (don't forget the series resistor)
• Not enough to run most relays, solenoids, or motors.
pinMode(pin#, INPUT) • Default if not specified
• Avoid pin 13 since it’s assigned to an onboard LED.
Pin 13 LED
digitalWrite()
• digitalWrite(Pin#, HIGH); o Set the pin to high voltage (either 3.3V or 5V)
• digitalWrite(Pin#, LOW); o Set the pin to low voltage (0V)
LED
http://www.societyofrobots.com/electronics_led_tutorial.shtml
External LED
Read Resistor
Blink 1 LED
1. Put 1 LED on the breadboard
2. Connect the LED to pin 10 of the Arduino
3. Blink the LEDs 10 & 13 together
4. Change the duration and intervals of blinking
5. Generate Morse code “· · · — — — · · ·”
Using Constants const int ontime = 2000; // LED ON time
const int offtime = 2000; // LED OFF time
void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(13, OUTPUT);
}
void loop() {
digitalWrite(13, HIGH); // set the LED on
delay(ontime); // wait
digitalWrite(13, LOW); // set the LED off
delay(offtime); // wait
}
Using Variables int ontime, offtime; // LED ON and OFF time
void setup() {
pinMode(13, OUTPUT);
ontime = 1000;
offtime = 1000;
}
void loop() {
digitalWrite(13, HIGH); // set the LED on
delay(ontime); // wait
digitalWrite(13, LOW); // set the LED off
delay(offtime); // wait
}
220Ω 220Ω
220Ω
+ +
+ _
_
_
Blink 3 LEDs 1. Put 1 Red LED, 1 Green LED, and 1 yellow LED on
the breadboard
2. Connect the LEDs to pins 8, 7, 6
3. Blink the LEDs together
4. Change the duration and intervals of blinking
Flow Control
for (int i=6; i<9; i++) {
for (int j=6; j<9; j++) {
digitalWrite(j, LOW);
}
digitalWrite(i, HIGH);
delay(flashtime);
}
Blink the LEDs Sequentially
1. Follow the order RGYRGYRGY…
2. Combine order with duration and interval.
3. Synchronize with a song of choice.
Read Digital Pin High
const int buttonPin = 6; // the number of the input pin
const int ledPin = 10; // the number of the LED pin
int buttonState = 0; // variable for reading the input status
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}
void loop(){
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
digitalWrite(ledPin, buttonState);
}
Operation
• 1 – 0 = 1;
• 1 – 1 = 0;
• !1 = 0;
• !0 = 1;
• 1 – LOW = HIGH;
• 1 – HIGH = LOW;
• !HIGH = LOW;
• !LOW = HIGH;
HIGH = 1
LOW = 0
Read Digital Pin Low
buttonState = !buttonState;
Or
buttonState = 1-buttonState;
Switch
Push To Turn ON
Push To Turn OFF
if … else…
// check if the pushbutton is pressed.
// if it is, the buttonState is HIGH:
if (buttonState == HIGH) {
// turn LED on:
digitalWrite(ledPin, HIGH);
}
else {
// turn LED off:
digitalWrite(ledPin, LOW);
}
Comparison Operations
>
<
==
!=
>=
<=
Optical Switch
Infrared Light of Optical Sensor
Optical Sensor
82Ω 47kΩ
A
K E
C
GND
+5V
Output White wire
82Ω 47kΩ
ON With Reflection
OFF With Reflection
Encoder
T (s)
Voltage
5V or HIGH
Non-Reflective
T (s)
Voltage
0V or LOW
Moving Reflections
T (s)
Voltage
0V or LOW
5V or HIGH
T (s)
Voltage
5V or HIGH
T (s)
Voltage
0V or LOW
T (s)
Voltage
0V or LOW
5V or HIGH
ω
T (s)
Voltage
0V or LOW
5V or HIGH
ω
Φ
Δt Δt
Angular Velocity
RPM =w *60/2p
Φ
• Determined from the daisy wheel design
Φ
Φ=2π/8
Other Encoder Wheels
High resolution
Multi-digit
Got Time?
unsigned long ms, us;
ms = millis(); //obtain the time in milli second since the
program started
us = micros(); // obtain the time in micro second
since the program started
Δt
• In the Setup()
time_last = 0; // Set the base time
• In the Loop()
time_current = millis(); //Get the current time
// After a trigger such as a rising or falling edge
Delta_t = time_current - time_last;
time_last = time_current; //New base time
Obtain a Trigger
• In Setup()
Optical_last = HIGH; //initial base status
• In Loop()
Optical_current = digitalRead(OpticalPin); // get current status of the pin
If (Optical_current != Optical_last) { //Is it a change?
Optical_last = Optical_current; //new base status
}
Serial Monitor
• Display the values of variables on a monitor
• Serial.begin(9600); // Start the serial monitor to get
feedback at 9600bit per second.
Set the serial monitor at the same baud rate
Speed Compares (bit/s)
• Serial: 2400, 9600, 19200, etc
• USB:1.5M, 12M, 3G, 10G
• Wi-Fi: 7.2M, 72.2M, 150M, 866.7M,
• Eithernet: 10M, 1G, 100G
• Harddrive (SATA): 1.5G, 3G, 6G
• Memory: 102G
• Note 1mB (MegaByte)=8mb
Display Values
Serial.print(”text"); // Display text in verbatian
Serial.print(variable); // Display the value of a variable
Serial.println(”text"); // Display text in verbatian then
change line
Serial.println(variable); // Display the value of a
variable then change line
Display Time In Serial Monitor
unsigned long ms, us;
int interval;
void setup() {
Serial.begin(9600); // Start the serial monitor to get feedback
// Make sure the baud rate of the serial monitor is set as 9600.
interval = 2000; // Initialize the interval between display
}
void loop() {
ms = millis(); //obtain the time in milli second since the program started
us = micros(); // obtain the time in micro second since the program started
Serial.print("Time: ms= "); // For easy reading on serial monitor
Serial.print(ms); // Display the time on the serial monitor
Serial.print(" , us= "); // Note that print() will just display variables
Serial.println(us); // println() will change line
delay(interval); // wait for next display
}
Encoder const int OpticalPin = 7; // the number of the pushbutton pin
const int ledPin = 13; // the number of the LED pin
unsigned long time_last, time_current; // variable to record time
int Optical_last, Optical_current; // variable for reading the optical sensor status
float phi = PI/8; // measured angle of each windlow on the wheel
float omega, rpm;
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(OpticalPin, INPUT);
Serial.begin(9600); // Start the serial monitor to get feedback
time_last = 0; // initialize the time
Optical_last = HIGH;
}
void loop(){
// read the state of the Optical sensor status:
Optical_current = digitalRead(OpticalPin);
digitalWrite(ledPin, Optical_current); //LED indicator of the speed
if (Optical_current != Optical_last) { // for faster operation, we can use Optical_current & Optical_last
time_current = millis(); //read the current time
omega = 1000* phi / (time_current - time_last); // calculate the angular velocity
rpm = omega * 30 / PI; // convert angular velocity to RPM
time_last = time_current;
Optical_last = Optical_current;
Serial.print("omega= "); // Display the result to serial monitor.
Serial.print(omega);
Serial.print("rad/sec, or ");
Serial.println(rpm);
}
}
Analog Read Int potPin = A0; // select the input pin for the
potentiometer. Total 6 pins from A0 to A5
Analog Input Pins
Analog Read potValue = analogRead(potPin); // read the value
from the potPin and store it in the variable
potValue.
An integer range from 0 (0V) to 1023 (5V). The resolution is 4.9mV per unit.
Use a Pot to Control an LED int potPin = A0; // select the input pin for the potentiometer
int ledPin = 13; // select the pin for the LED
int potValue = 0; // variable to store the value coming from the sensor
void setup() {
pinMode(ledPin, OUTPUT); // declare the ledPin as an OUTPUT
Serial.begin(9600); // Start the serial monitor to get feedback
}
void loop() {
potValue = analogRead(potPin); // read the value from the potentiometer
Serial.print("Potentiometer value is ");
Serial.println(potValue);
digitalWrite(ledPin, HIGH); // turn the ledPin on
delay(potValue); // stop the program for <potValue> milliseconds
digitalWrite(ledPin, LOW); // turn the ledPin off
delay(potValue); // stop the program for for <potValue> milliseconds
}
Servo
#include <Servo.h> // First need to include a servo
header file.
Servo myservo; // Create a servo object myservo
myservo.attach(7); // attaches the servo on pin 7 to
the servo object
myservo.write(val);
// Set the servo position according to the variable val.
The range of val is from 0 to 179.
To ensure the range of val, we can map it from any
other values, e.g., the reading from a pot:
val = map(val, 0, 1023, 0, 179);
Use a Pot to Control a Servo
#include <Servo.h> // Include the servo header file
Servo myservo; // create servo object to control a servo
int potpin = A0; // analog pin used to connect the potentiometer
int val; // variable to read the value from the analog pin
void setup()
{
myservo.attach(7); // attaches the servo on pin 7 to the servo object
}
void loop()
{
val = analogRead(potpin); // reads the value of the potentiometer (value between 0 and 1023)
val = map(val, 0, 1023, 0, 179); // scale it to use it with the servo (value between 0 and 180)
myservo.write(val); // sets the servo position according to the scaled value
delay(15); // waits for the servo to get there
}
