The document discusses principles of variable output voltage using pulse width modulation (PWM) and provides examples of driving devices like fans and stepper motors using Arduino. It explains the role of sensors in detecting environmental changes and includes sample code for interfacing various sensors and controlling actuators. The document also outlines learning outcomes related to building mechatronic systems with Arduino components.

1. 1

2. SESSION 2
2

3. What is the principle behind variable
output voltage?
PWM Concept
3

4. What is PWM(Pulse width Modulation)?
4

5. PWM power control
5

6. Fan example
You can run the fan at
different speeds
How do you make the choice
of speed?
Table fan button
6

7. Keypad Module
7

8. Keypad Program
8

9. #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};
9

10. 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);
}
}
10

11. 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
11

12. Most used sensors for Arduino
1. Temperature + Humidity Sensor
This is a temperature/humidity sensor. It
monitors the ambient temperature or
humidity.
12

13. 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.
13

14. IR sensor Program
14

15. //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
{
15

16. digitalWrite(13, HIGH); // set the LED on
}
else
{
digitalWrite(13, LOW); // set the LED off
}
delay(1000); // wait for a second
}
Contd..
16

17. Do you remember which actuator was used in
this Access gate?
Stepper Motor
17

18. Working principle
18

19. • 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
19

20. • 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
20

21. Activity 2.1
Type : Team of 2 Duration : 30 Minutes
Write a program to run stepper motor in
clockwise direction
21

22. Stepper Motor Speed Control
22

23. /*
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);
23

24. 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
}
24

25. Topic Learning Outcomes
At the end of the topic you should be able to
1. Interface a sensor/s, device/s with Arduino
for data acquisition and display the data.
2. Interface Actuators with Arduino to Control
motion to build an application.
3. Build a mechatronic system using Arduino,
sensors, actuators and modules.
25