The document discusses the second part of a project aimed at creating a smart bunk bed child monitoring system that uses various sensors to relay information to a mobile application via Bluetooth. It details the components required, including Arduino, multiple types of sensors, and the working principle of the system, which allows parents to monitor their child's status in real-time. The project emphasizes the transition from wired to wireless communication between the sensors and the mobile application for enhanced monitoring capabilities.

1. SMART BUNK BED CHILD MONITORING SYSTEM |
BABY MONITORING SYSTEM BY ANDROID
APPLICATION(PART-2)
This is a second part of project. We have already discussed about to 1st part of this
project. If you did not read article of part-01. So click on link. We told all about the
part-1. We told about to know all sensors. So today we are going to expand the
project of part -1. Which is our second part (part-2). Before this, we saw in part-1
that all the types of sensors we had in our bunk bed , through which we were
monitoring. All these sensors were connected to arduino board and the data that was
received by all the different types of sensors used to send that the data through the

2. microcontroller(atmega328) and the microcontroller used to turn on buzzer for alerts
parents. All the data processes with wired. All sensors,buzzer and arduino
communicate to each other only with wired. In this second part(part-2) of the project,
we will transfer the data ,received by all the connected sensors through the arduino.
Direct sensor's data transfer Arduino to android application of smartphone with
wireless.
COMPONENT REQUIRED
1.)Arduino uno.
2.)Mq2 gas sensor.
3.)Wet sensor.
4.)Piezo electric sensor.
5.) HC-SR04 Ultrasonic sensor.
6.)DHT11 Temperature module.
7.)HC-05 Bluetooth module.
8.)12v, 1 amp power supply adapter.
9.)Plywood for frame(Bunk bed).
10.) Some wires.
ARDUINO UNO

3. The Arduino Uno is an open-source microcontroller board based on the Microchip
ATmega328P microcontroller and developed by Arduino.cc. The board is equipped with sets
of digital and analog input/output (I/O) pins that may be interfaced to various expansion
boards (shields) and other circuits.[ The board has 14 digital I/O pins (six capable of PWM
output), 6 analog I/O pins, and is programmable with the Arduino IDE (Integrated
Development Environment), via a type B USB cable. It can be powered by the USB cable or
by an external 9-volt battery, though it accepts voltages between 7 and 20 volts. It is similar
to the Arduino Nano and Leonardo. The hardware reference design is distributed under a
Creative Commons Attribution Share-Alike 2.5 license and is available on the Arduino
website. Layout and production files for some versions of the hardware are also available.
Mq2 GAS SENSOR

4. Mq2 gas sensor is a type of sensor.Which detects Smoke or Gas in the air. This is
made metal oxide semiconductor (MOS) . We know as Chemiresistor .When a
smoke or gas comes into contact with gas sensor . The MOS material is heated then
stars causing the resistance value change according to concentration of gas or
smoke. And the resistance value level of sensor is changed depend up on the type
of gases presents in the atmosphere of Mq2 sensor.
There are following types of gases detect by Mq2 Gas sensor
● LPG.
● Propane.
● Methane.
● Butane.
● CO.
● Alcohol.
● Hydrogen etc.
Mq2 gas sensor works on 5v dc and draw at least 800 mW. Smoke sensor has a potentiao
meter .We can adjust the sensitivity of gas sensor module and one Digital output voltage

5. pin(D0) and one Analog output voltage pin (A0) for read data from the sensor. and it has
power led for Indication voltage.and final last output data indication led.
WET SENSOR OR SOIL MOISTURE SENSOR
Soil moisture sensor or wet sensor an electronic sensor. Which is used in the irrigation
system or any wet or dry detect . Soil sensor measure the volumetric water content in the
soil. sensor is low cost, less power consume and easy to interface to Arduino. Sensor operate
to 3.3V to 5V DC power supply.
PIEZO ELECTRIC

6. A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in
pressure, acceleration, temperature, strain, or force by converting them to an electrical charge.
The prefix piezo- is Greek for 'press' or 'squeeze'.
ULTRASONIC SENSOR

7. The HC-SR04 Ultrasonic sensor distance is distance measuring sensor. This
sensor uses sonar to determine distance to any object, It provide a some
no-contact range detection with high accuracy. You can easy-to-use and low
power consume and buy low cost ultrasonic use common in robotic. And other
automation field. Ultrasonic range is detect object within 2 cm to 400 cm but
sensor get better result within 10 cm to 250 cm.
There are Three sections of HC-SR04 ultrasonic sensor:-
1.Transmitter
2.Receiver
3.Circuit of HC-SR04
DHT-11

8. DHT11 sensor module is a type of sensor. Which measures the temperature and
humidity of the environment in single wire. It has a restive humidity sensor and NTC
(Negative Temperature Coefficient) temperature sensor or Thermistor sensor and
8-bit microcontroller chip, that are providing cost effectiveness, anti-interfacing ability,
excellent quality and also fast response. There is a 3 pin dht11 sensor and 4 pin
dht11 sensor available in the market, so you can buy either of them. These are both
same. 3 pin dht11 to 1. GND 2. VCC 3. Signal pin. And the 4 pin sensor has 1. GND
2. VCC 3. Signal pin 4. NC (no connection) pin. When you interface with arduino,
only 3 pins of dht11 use GND, VCC and signal pins of dht11 sensor module.
HC-05 Bluetooth Module

9. HC-05 Bluetooth module is a wireless module. It is a specially designed for wireless
data transfer and receiver.
It has 6 pin
1.)EN Pin.
2.)TXD Pin.
3.)RXD Pin.
4.)VCC Pin(3.3v To 5v)
5.)GND Pin.
6.)State Pin.

10. PIN OUT:-
HC-05 ARDUINO UNO
VCC +5V
GND GND
TX RX
RX TX
HC-SRO4 ARDUINO UNO
VCC +5V
GND GND
TRIG D2
ECHO D3
MQ2 ARDUINO UNO
VCC +5V
GND GND
DO D4
WET SENSOR ARDUINO UNO

11. VCC +5V
GND GND
DO D5
BUZZER ARDUINO UNO
+ D6
GND GND
DHT-11 SENSOR ARDUINO UNO
VCC +5V
GND GND
DO D7
PIEZO ELECTRIC ARDUINO UNO
+ A0
- GND
WORKING PROCEDURE

12. Download app
The working principle of this project is very simple. How do parents know
if their child is in the bed of the children's bedroom without enter. You
can easily monitor by the mobile app. All sensors live data transfer by
Bluetooth to your mobile Bluetooth for witch you can easily monitor in
app from anywhere. Bunk bed has attached 4 sensors hc-sro4

13. ultrasonic sensor,mq2 gas sensor, soil moisture or wet sensor and piezo
electric sensor ,dh11 temperature sensor and buzzer. All these sensors
are connected to arduino board and all sensors and arduino board
operates by 5 volt dc power supply . When the children go to sleep on
the bed or through the stair , the ultrasonic sensor detects the children
and the data transfer Arduino's Bluetooth to mobile and show live status
in app .it is detected . So that parents can easily know that their children
are inside the bed or not. Whenever children come in the bed, it detects
the piezo inside the bed due to electric pressure and sends a signal to
the arduino and arduino send data through the hc-05 bt to your app as
soon as it is detected. So this is how parents know that their on the bed.
And when the child spills water in the bed or urinates suddenly while
sleeping, so the wet sensor in the bed makes sensor sens and live
status show your mobile app .so that the parents know that the bed is
wet And changes the bed sheet in time so that infection can be easily
avoided. And when there is a gas leakage due to some reason or
burning of something than the gas sensor in the bunk bed detects then
show data in app so that the parents know easily So this kind of smart
bunk bed child monitoring system works.
There is some processes for witch you can all sensors data see in
your mobile app.

14. First of all the project's Bluetooth(hc-05) should be turned on when
bluetooth is on then bluetooth continuously starts blinking. And as soon
as the hc-05 bluetooth is connected to the bluetooth of our mobile
hc-05's led blinking stop.

15. 1.)We have to give dc power supply our project for witch hc-05 bluetooth
provided 5v dc.
2.)Then after we have to go our mobile settings just click on settings

16. then after will show Bluetooth icon just click on it.
3.)Then we have to on the bluetooth device. Off to On and after on bt
then starts showing all available bluetooth devices in our around. We
have to only find out hc-05 bluetooth. When we will get hc-05 bt
of project then click on.

18. 4.)After click on then we have to pair hc-05 bluetooth so we
have to put 1234 number and ok then successfully paired
bt.

20. 5.)Then after we have to download apk file after downloaded
apk file then click on and install apk file simply

21. 6.)After install app then open application of baby monitoring
system.

22. After as soon as you open the application, you will get to see
some interface like this. So right now you won't see any live
status of sensors of bunk bed because mobile bluetooth is not
yet connected to hc-05 bluetooth of project. So we have to
connect the bluetooth for witch send data from arduino through
in our mobile.

23. 7.)Just click on bt list of app and show paired device so we have to find out hc-05
name and click on and as soon as we click on hc-05 bt and connect, then as soon as
it is connected, Live data of all the sensors in the bunk bed starts showing.
8.)So some data look like this when sens the sensors.

31. In this way show all sensor's data status in our mobile app.
SCHEMATICS DIAGRAM

32. CODE
//ultrasonic sensor
int trigPin=2;
int echoPin=3;
int duration;
int distance;
//gas sensor
int mq2 =4;
int val1;

33. //piezo sensor
int piezo= A0;
int val2;
//wet sensor
int wet = 5;
int val3;
// Buzzer
int buzzer=6;
//Temperature sensor
#include "DHT.h"
#define DHTPIN 7 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT 11
DHT dht(DHTPIN, DHTTYPE);
void setup()
{
// put your setup code here, to run once:
Serial.begin(9600);
dht.begin();
// Serial.println(F("DHTxx test!"));

34. pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
pinMode(buzzer,OUTPUT);
pinMode(mq2,INPUT);
pinMode(piezo,INPUT);
pinMode(wet,INPUT);
}
void ultrasonicsensor()
{
digitalWrite(trigPin, HIGH);
digitalWrite(trigPin, LOW);
int duration = pulseIn(echoPin, HIGH);
int distance = (duration/2) / 29.1;
Serial.print(distance);
Serial.print("/");
}
void mq()
{
val1=digitalRead(mq2);
Serial.print(val1);
Serial.print("/");

35. }
void piezo_sensor()
{
val2=analogRead(piezo);
Serial.print(val2);
Serial.print("/");
}
void wet_sensor()
{
val3=digitalRead(wet);
// Serial.print("Wet=");
Serial.print(val3);
Serial.print("/");
}
void temperature()

36. {
// delay(2000);
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(true);
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t) || isnan(f)) {
Serial.println(F("Failed to read from DHT sensor!"));
return;
}
// Compute heat index in Fahrenheit (the default)
float hif = dht.computeHeatIndex(f, h);
// Compute heat index in Celsius (isFahreheit = false)
float hic = dht.computeHeatIndex(t, h, false);
// Serial.print(h);
Serial.print(t);
Serial.print("/");
delay(1000);
// Serial.print(f);

37. }
void loop() {
// put your main code here, to run repeatedly:
ultrasonicsensor();
//wet_sensor();
piezo_sensor();
mq();
wet_sensor();
temperature();
}