Sensors and Actuators in Arduino, Introduction

Input/Output (Sensor and Actuators)
Workshop on Arduino

Input/Output (Sensor and Actuators)
• Input and Output
 State Input Output
 Data Input Output
• Sensors
• Actuators

Input/Output
• Example Code
// Switch test program
int ledPin = 12; // LED is connected to pin 12
int switchPin = 2; // Switch connected to digital pin 2
int val; // variable for reading the pin status
void setup() {
pinMode(ledPin, OUTPUT); // Set the LED pin as output
pinMode(switchPin, INPUT); // Set the switch pin as input
}
void loop(){
val = digitalRead(switchPin); // read input value and store it in val
if (val == HIGH) { // check if the button is pressed
digitalWrite(ledPin, HIGH); // turn LED on
}
if (val == LOW) { // check if the button is not pressed
digitalWrite(ledPin, LOW); // turn LED off
}
}

State input
• Pull Down and Pull up

State input
• Example code
/* * Switch and LED test program */
int ledPin = 12; // LED is connected to pin 12
int switchPin = 2; // switch is connected to pin 2
int val; // variable for reading the pin status
void setup() {
pinMode(ledPin, OUTPUT); // Set the LED pin as output
pinMode(switchPin, INPUT); // Set the switch pin as input
}
void loop(){
val = digitalRead(switchPin); // read input value and store it in val
if (val == LOW) { // check if the button is pressed
digitalWrite(ledPin, HIGH); // turn LED on
}
if (val == HIGH) { // check if the button is not pressed
digitalWrite(ledPin, LOW); // turn LED off
}
}

Input/Output
Data Input Output

Data Input Output
#include <dht.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
dht DHT;
#define DHT11_PIN 2
void setup() {
lcd.init();
lcd.clear();
lcd.backlight(); // Make sure backlight is on
}
void loop() {
DHT.read11(DHT11_PIN);
int current_temp = DHT.temperature;
int current_humi = DHT.humidity;
lcd.setCursor(0, 0);
lcd.print("Temp: ");
lcd.print(current_temp);
lcd.print((char)223); //Shows degrees
character
lcd.print("C");
lcd.setCursor(0, 1);
lcd.print("Humidity: ");
lcd.print(current_humi);
lcd.print("%");
delay(1000);
}

Serial Library
/* * Hello World! *
* This is the Hello World! for Arduino.
* It shows how to send data to the computer
*/
void setup() // run once, when the sketch starts
{
Serial.begin(9600); // set up Serial library at 9600 bps
}
void loop() // run over and over again
{
Serial.println("Hello world!"); // prints hello with ending line break
delay(1000);
}

Serial Communication (UART communication)

Serial Communication
/* * Hello World! *
* This is the Hello World! for Arduino.
* It shows how to send data to the computer
*/
{
}
{
Serial.println("Hello world!"); // prints hello with ending line break
delay(1000);
}

/* * Math is fun! */
int a = 5;
int b = 10;
int c = 20;
{
Serial.println("Here is some math: ");
Serial.print("a = ");
Serial.println(a);
Serial.print("b = ");
Serial.println(b);
Serial.print("c = ");
Serial.println(c);
Serial.print("a + b = "); // add
Serial.println(a + b);
Serial.print("a * c = "); // multiply
Serial.println(a * c);
Serial.print("c / b = "); // divide
Serial.println(c / b);
Serial.print("b - c = "); // subtract
Serial.println(b - c);
}
void loop() {
}

/* * Drive size calculator! */
int drive_gb = 5;
int drive_mb;
{
Serial.print("Your HD is ");
Serial.print(drive_gb);
Serial.println(" GB large.");
drive_mb = 1024 * drive_gb;
Serial.print("It can store ");
Serial.print(drive_mb);
Serial.println(" Megabytes!");
}
void loop() // we need this to be here even though its empty
{
}

Type Size
(bits)
Size (bytes) Minimum Value Maximum Value
unsigned byte 8 1 0 255
byte 8 1 -128 127
unsigned int 16 2 0 65535
int 16 2 -32768 32767
unsigned long 32 4 0 4294967295
long 32 4 -2147483648 2147483647

/* * Drive size calculator! */
int drive_gb = 100;
long drive_mb;
long drive_kb;
long real_drive_mb;
long real_drive_kb;
{
Serial.print("Your HD is ");
Serial.print(drive_gb);
Serial.println(" GB large.");
drive_mb = drive_gb;
drive_mb = drive_mb * 1024;
drive_kb = drive_mb * 1024;
Serial.print("In theory, it can store ");
Serial.print(drive_mb);
Serial.print(" Megabytes, ");
Serial.print(drive_kb);
Serial.println(" Kilobytes.");
real_drive_mb = drive_gb;
real_drive_mb = real_drive_mb * 1000;
real_drive_kb = real_drive_mb * 1000;
Serial.print("But it really only stores ");
Serial.print(real_drive_mb);
Serial.print(" Megabytes, ");
Serial.print(real_drive_kb);
Serial.println(" Kilobytes.");
Serial.print("You are missing ");
Serial.print(drive_kb - real_drive_kb);
Serial.println(" Kilobytes!");
}
{
}

Serial Communication (UART communication)
//Transmitter and Recevier
int button = 7;
int LED = 8;
char message; // message character
void setup() {
Serial.begin(9600); // start communication
pinMode(button, INPUT); // input button 1
pinMode(LED, OUTPUT); // input button 2
}
void loop() {
digitalWrite(LED,LOW);
if (Serial.available()) // while message received
{
message = Serial.read(); // read message
if (message == '1') // if the message contain character one
{
digitalWrite(LED, HIGH); // switch led one ON
}
}

if (digitalRead(button)==HIGH) // while button is pushed
{
Serial.write('1'); // send this Character
}
delay(20); // delay before sending next message
}

I2C Communication
// Master Code
#include <wire.h>
int x = 0;
void setup() { // Start the I2C Bus as Master
Wire.begin();
}
void loop() {
Wire.beginTransmission(9); // transmit to device #9
Wire.write(x); // sends x
Wire.endTransmission(); // stop transmitting
x++; // Increment x
if (x > 5) x = 0; // `reset x once it gets 6
delay(500);
}

I2C Communication
// Slave Code
#include <Wire.h>
int LED = 13;
int x = 0;
void setup() {
pinMode (LED, OUTPUT); // Define the LED pin as Output
Wire.begin(9); // Start the I2C Bus as Slave on address 9
// Attach a function to trigger when something is received.
Wire.onReceive(receiveEvent);
}
void receiveEvent(int bytes) {
x = Wire.read(); // read one character from the I2C
}
void loop() {
if (x == '0') { //If value received is 0 blink LED for 200 ms
digitalWrite(LED, HIGH);
delay(200);
digitalWrite(LED, LOW);
delay(200);
}

//If value received is 3 blink LED for 400 ms
if (x == '3') {
digitalWrite(LED, HIGH);
delay(400);
digitalWrite(LED, LOW);
delay(400);
}
}

SPI Communication (Serial Peripheral Interface)

// Master Code
#include <SPI.h>
void setup (void) {
Serial.begin(115200); //set baud rate to 115200 for usart
digitalWrite(SS, HIGH); // disable Slave Select
SPI.begin ();
SPI.setClockDivider(SPI_CLOCK_DIV8);//divide the clock by 8
}
void loop (void) {
char c;
digitalWrite(SS, LOW); // enable Slave Select // send test string
for (const char * p = "Hello, world!r" ; c = *p; p++) {
SPI.transfer (c);
Serial.print(c);
}
digitalWrite(SS, HIGH); // disable Slave Select
delay(2000);
}

// Slave Code
#include <SPI.h>
char buff [50];
volatile byte indx;
volatile boolean process;
void setup (void) {
Serial.begin (115200);
pinMode(MISO, OUTPUT); // have to send on master in so it set as output
SPCR |= _BV(SPE); // turn on SPI in slave mode
indx = 0; // buffer empty
process = false;
SPI.attachInterrupt(); // turn on interrupt
}
ISR (SPI_STC_vect) // SPI interrupt routine {
byte c = SPDR; // read byte from SPI Data Register
if (indx < sizeof buff) {
buff [indx++] = c; // save data in the next index in the array buff
if (c == 'r') //check for the end of the word
process = true;

}
}
void loop (void) {
if (process) {
process = false; //reset the process
Serial.println (buff); //print the array on serial monitor
indx= 0; //reset button to zero
}
}

Some Arduino Projects
1) Arduino-based Home Automation System
2) Smart Irrigation Project
3) Human Following Robot
4) Fire Fighter Robot
5) Medicine Reminder using Arduino
6) Arduino-based Weather Station
7) Digital Thermometer using Arduino
8) Arduino-based Security System
9) LED Light Device using Arduino
10) Soil Moisture Monitoring Arduino
1. Automation Systems using Arduino
2. Arduino-based Clock with Alaram
3. Door Lock System with Arduino
4. Arduino Nano BLE 33 Sense Game Controller
5. Color Detection using TCS-3200 and LCD Display
6. Touch Dimmer circuit
7. Precise Motor speed measurement
8. Gas Detector Arduino project
9. Security System using Ultrasonic Sensor
10.Water flow and volume measurement

Sensors and Actuators in Arduino, Introduction

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