The document discusses keypad and sensor modules for Arduino. It provides code to read input from a 4x4 keypad and display it on the serial monitor. It then defines different sensors like temperature, humidity, and IR sensors. It provides an IR sensor code to detect objects and toggle an LED. It also discusses stepper motors and provides code to control the speed and direction of a stepper motor.

1. Keypad Module
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2. Keypad Program
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3. #include <Keypad.h>
const byte ROWS = 4;
const byte COLS = 4;
char hexaKeys[ROWS][COLS] = {
{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6};
byte colPins[COLS] = {5, 4, 3, 2};
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4. Contd..
Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins,
ROWS, COLS);
void setup(){
Serial.begin(9600);
}
void loop(){
char customKey = customKeypad.getKey();
if (customKey){
Serial.println(customKey);
}
}
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5. SENSORS
What is a sensor?
“A sensor is an object whose purpose is to detect events
or changes in its environment, and then provide a
corresponding output”.
Why do we need sensor?
• A sensor is the guy who provides data to the a system
via its input.
• We need sensor to feed data to the system and tells
the controller when to take action
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6. Most used sensors for Arduino
1. Temperature + Humidity Sensor
This is a temperature/humidity sensor. It
monitors the ambient temperature or
humidity.
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7. 2. IR Sensor:
• This is a multipurpose infrared sensor which can
be used for color detection.The sensor provides a
digital as well as analog output. An on board LED
is used to indicate the presence of an object. This
digital output can be directly connected to an
Arduino, Raspberry Pi or any other
microcontroller to read the sensor output.
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8. IR sensor Program
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9. //IR sensor with digital input at pin no. 2
const int IR_Sensor=2;
void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED on Arduino boards:
pinMode(13, OUTPUT);
//Pin 2 is connected to the output of IR_Sensor
pinMode(IR_Sensor,INPUT);
}
void loop() {
if(digitalRead(IR_Sensor)==HIGH) //Check the sensor output
{
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10. digitalWrite(13, HIGH); // set the LED on
}
else
{
digitalWrite(13, LOW); // set the LED off
}
delay(1000); // wait for a second
}
Contd..
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11. Do you remember which actuator was used in
this Access gate?
Stepper Motor
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12. Working principle
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13. • Stepper motors are called as Digital motor
– It takes digital input to move by a step.
• Stepper motor is specified by step angle of say
200 steps per revolution
– 1.8 degree per step
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14. • To move a step we need to provide a digital
input sequence to windings.
• The sequence for bipolar/unipolar is
1000 // 1st step
0100 // 2nd step
0010 // 3rd step
0001 // 4th step
1000 // repeat of sequence for 5th step
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15. Stepper Motor Speed Control
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16. /*
Stepper Motor Control - one revolution
This program drives a unipolar or bipolar stepper motor.
The motor is attached to digital pins 8 - 11 of the Arduino.
The motor should revolve one revolution in one direction, then
one revolution in the other direction.
*/
#include <Stepper.h>
const int stepsPerRevolution = 200; // change this to fit the number of steps per
revolution
// for your motor
// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);
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17. Contd..
void setup() {
// set the speed at 60 rpm:
myStepper.setSpeed(60);
// initialize the serial port:
Serial.begin(9600);
}
void loop() {
// step one revolution in one direction:
Serial.println("clockwise");
myStepper.step(stepsPerRevolution);
delay(500);//Without delay stepper motor will rotate continuosly
}
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