Design of wireless sensor network for building management systems

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CHAPTER 1
INTRODUCTION
1.1 Problem overview and motivation:
Is it possible to introduce wireless technology into building automation systems? If so,
how can it be done in a standardized way so that the least amount of effort is needed, both
in the wireless sensor network and in the building automation system?
1.2 Objective:
The primary objective of such a system is to achieve an optimal level of control of
occupant comfort while minimizing energy use. Monitoring temperature, pressure,
humidity occupancy and flow rates are key functions of modern building control systems.
A BMS has to be properly installed and commissioned for optimal operation and to realize
potential savings. Energy efficiency can be optimized by a combination of scheduling,
controlling temperature and using system economizer functions. Sensors out of calibration
can lead to enormous energy waste. Integration of other auxiliary functions such as fire
detection and suppression and security and occupancy detection can result in substantial
cost savings.
1.3 Basics:
Complete autonomous control of an entire facility is the goal that any modern
automation system attempts to achieve. The distributed control system - the computer
networking of electronic devices designed to monitor and control the mechanical, security,
fire, lighting, HVAC and humidity control, and ventilation systems in a building or across
several campuses.
The Building Automation System (BAS) core functionality is to keep building
climate within a specified range, light rooms based on an occupancy schedule, monitor

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performance and device failures in all systems and provide malfunction alarms.
Automation systems reduce building energy and maintenance costs compared to a non-
controlled building. Typically they are financed through energy and insurance savings and
other savings associated with pre-emptive maintenance and quick detection of issues.
A building controlled by a BAS is often referred to as an intelligent building or
"smart building". Commercial and industrial buildings have historically relied on robust
proven protocols like BACnet.
Almost all multi-story green buildings are designed to accommodate a BAS for the
energy, air and water conservation characteristics. The electrical device demand response
is a typical function of a BAS, as is the more sophisticated ventilation and humidity
monitoring required of "tight" insulated buildings. Most green buildings also use as many
low-power DC devices as possible, typically integrated with power over Ethernet wiring,
so by definition always accessible to a BAS through the Ethernet connectivity. Even a
Passivhaus design intended to consume no net energy whatsoever will typically require a
BAS to manage heat capture, shading and venting, and scheduling device use.
Fig 1.1 A simple example of building automation system

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CHAPTER 2
LITERATURE SURVEY
Literature Survey:
A Survey on an Efficient IOT Based Smart building proposes an efficient
implementation for IoT for monitoring and automation system and it uses portable devices
as a user interface.
Portable devices can communicate with the home automation network through an
Internet gate, employing low power communication protocols like Zigbee, Wi-Fi, etc.
This also describes how to provide a fully smart environment and condition
monitoring by various sensors like Temperature, Humidity, Light, and Level for providing
necessary data to automatic detection and resolution of any problem in the devices.
The goal of this master thesis is to investigate if it is possible to make a successful
integration of interconnecting wireless sensor network technology into building
automation systems. For the integration to be successful the solution should be designed
and constructed in a standardized way. The key points with making a standardized
integration are that the solution will fit into, and make use of, existing infrastructure;
provide data exchange in a vendor-independent way, and increase the potential of
expanding the solution to other functional domains such as security, light control, and fire
alarms. The solution should make use of standardized communication protocols or at least
be able to communicate with standardized communication protocols. The thesis should end
up in a measurable proof of concept design and implementation of a wireless sensor
networking node with building automation capabilities.

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CHAPTER 3
BLOCK DIAGRAM & FLOW CHART
3.1 BLOCK DIAGRAM
Main Station:
Fig 3.1 Block diagram of the transmitter
Receiversection:
Fig 3.2 Block diagram of the receiver
5V
Node
MCU
RF
5V Power
Supply
RF
Arduino
DHT 11 Sensor
DC Fan
LED
LDR
Smoke Sensor
Android application

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3.2 Flowchart:
Transmitter:
Fig 3.3 Transmitter Flowchart
Receiver:
Fig 3.4 Receiver Flow chart

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CHAPTER 4
HARDWARE DESCRIPTION
4.1 Hardware Components:
Hardware components are
1. Arduino Nano
2. Power Supply
3. LDR
4. DC Fan
5. DHT 11 Sensor
6. LED
7. Smoke Sensor
8. Node MCU
9. RF Module

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4.1.1 Arduino Nano:
Fig 4.1 Arduino Nano
The Arduino microcontroller is an easy to use yet powerful single board computer
that has gained considerable traction in the hobby and professional market. The Arduino is
open-source, which means the hardware is reasonably priced and development software is
free. Arduino nano differs from other Arduino as it very small so it suitable for small-sized
projects and it supports breadboards so it can be plugged with other components in only
one breadboard.

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Table 4.1 Specifications
In the Arduino Nano 2.x version, it still used ATmega168 microcontroller while
the Arduino Nano 3.x version already used ATmega328 microcontroller. ATmega168 is
a low-power CMOS 8-bit microcontroller based on the AVR® enhanced RISC
architecture.
Microcontroller Atmel ATmega168 or ATmega328
OperatingVoltage (logiclevel) 5 V
Input Voltage(recommended) 7-12 V
Digital I/O Pins 6-20 V
Analog Input Pins 14 (of which6 provide PWMoutput)
Dc CurrentPer I/O Pins 8
Flash Memory 40 mA
SRAM 16 KB (ATmega168) or 32 KB (ATmega328) of
which 2 KB usedby bootloader
EEPROM 1 KB (ATmega168) or 2 KB (ATmega328)
Clock Speed 16 MHz
Dimensions 0.73” x 1.70”
Length 45 mm
Width 18 mm
Weight 5 g

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Fig 4.2 Arduino Nano Pin Configuration
The Serial Peripheral Interface (SPI) IN PINS 7,8,13,14 AND 15
Serial Peripheral Interface (SPI) is a synchronous serial data protocol used by
microcontrollers for communicating with one or more peripheral devices quickly over short
distances. It can also be used for communication between two microcontrollers.
With an SPI connection, there is always one master device (usually a microcontroller)
that controls the peripheral devices. Typically, there are three lines common to all the
devices:
 MISO (Master In Slave Out) - The Slave line for sending data to the master,
 MOSI (Master Out Slave In) - The Master line for sending data to the peripherals,
 SCK (Serial Clock) - The clock pulses which synchronize data transmission generated
by the master and one-line specific for every device:

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 SS (Slave Select) - the pin on each device that the master can use to enable and disable
specific devices.
When a device's Slave Select pin is low, it communicates with the master. When it's
high, it ignores the master. This allows you to have multiple SPI devices sharing the same
MISO, MOSI, and CLK lines.
4.1.2 Power Supply:
The input to the circuit is applied from the regulated power supply. The a.c. input
i.e., 230V from the mains supply is step down by the transformer to 12V and is fed to a
rectifier. The output obtained from the rectifier is a pulsating d.c voltage. So to get a pure
d.c voltage, the output voltage from the rectifier is fed to a filter to remove any a.c
components present even after rectification. Now, this voltage is given to a voltage
regulator to obtain a pure constant dc voltage.
4.1.3 Light Dependent Resistor:
LDRs or Light Dependent Resistors are very useful, especially in light/dark sensor
circuits. Normally the resistance of an LDR is very high, sometimes as high as 1,000,000
ohms, but when they are illuminated with light, the resistance drops dramatically.
Thus in this project, LDR plays an important role in switching on the lights based
on the intensity of light i.e., if the intensity of light is more (during daytime) the lights will
be in off condition. And if the intensity of light is less (during nights), the lights will be
switched on.

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Fig 4.3 LDR
This is an example of a light sensor circuit: When the light level is low the resistance
of the LDR is high. This prevents current from flowing to the base of the transistors.
Consequently, the LED does not light. However, when light shines onto the LDR its
resistance falls and current flows into the base of the first transistor and then the second
transistor. The LED glows. The preset resistor can be turned up or down to increase or
decrease resistance, in this way it can make the circuit more or less sensitive.
4.1.4 Driver Circuit Fan:
Digital systems and microcontroller pins lack sufficient current to drive the circuits
like relays, buzzer circuits, DC fans, etc. While these circuits require around 10milli amps
to be operated, the microcontroller’s pin can provide a maximum of 1-2milli amps current.
For this reason, a driver such as a power transistor is placed in between the microcontroller
and the device.
The operation of this circuit is as follows:
The input to the base of the transistor is applied from the microcontroller port pin
P1.0. The transistor will be switched on when the base to emitter voltage is greater than
0.7V (cut-in voltage). Thus when the voltage applied to the pin P1.0 is high i.e., P1.0=1
(>0.7V), the transistor will be switched on and thus the fan will be ON.

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When the voltage at the pin P1.0 is low i.e., P1.0=0 (<0.7V) the transistor will be
in off state and the fan will be OFF. Thus the transistor acts as a current driver to operate
the fan accordingly.
Fig 4.4 DC Fan
4.1.5 DHT 11 Sensor:
DHT11 Temperature & Humidity Sensor features a temperature & humidity sensor
complex with a calibrated digital signal output. By using the exclusive digital-signal-
acquisition technique and temperature & humidity sensing technology, it ensures high
reliability and excellent long-term stability. This sensor includes a resistive-type humidity
measurement component and an NTC temperature measurement component, and connects
to a high-performance 8-bit microcontroller, offering excellent quality, fast response, anti-
interference ability, and cost-effectiveness.
Fig 4.5 DHT 11 Sensor

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Each DHT11 element is strictly calibrated in the laboratory that is extremely
accurate on humidity calibration. The calibration coefficients are stored as programs in the
OTP memory, which are used by the sensor’s internal signal detecting process. The single-
wire serial interface makes system integration quick and easy. Its small size, low power
consumption, and up-to-20 meter signal transmission making it the best choice for various
applications, including those most demanding ones. The component is a 4-pin single row
pin package. It is convenient to connect and special packages can be provided according to
users’ request.
4.1.6 LED:
Fig 4.6 LED
The most important requirement that a light source has to meet to serve
communication purposes is the ability to be switched on and off repeatedly in very short
intervals. By utilizing the advantage of fast switching characteristics of LED‟s compared
with the conventional lightning, the LED illumination is used as a communication source.
Since the illumination exists everywhere, it is expected that the LED illumination device
will act as a lighting device and a communication transmitter simultaneously everywhere
shortly.

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Typically, red, green, and blue LEDs emit a band of spectrum, depending on the
material system. The white LED draws much attention to the illumination devices.
Comparing the LED illumination with the conventional illumination such as fluorescent
lamps and 14 incandescent bulbs, the LED illumination has many advantages such as high
efficiency, environment-friendly manufacturing, design flexibility, long lifetime, and
better spectrum performance.
LEDs emit light when energy levels change in the semiconductor diode. This shift
in energy generates photons, some of which are emitted as light. The specific wavelength
of the light depends on the difference in energy levels as well as the type of semiconductor
material used to form the LED chip.
The solid-state design allows LEDs to withstand shock, vibration, frequent
switching i.e; electrical on and off a shockand environmental i.e; mechanical shocks
extremes without compromising their famous long life typically 100,000 hours or more.
The basic LED consists of a semiconductor diode chip mounted in the reflector cup of a
lead frame that is connected to electrical (wire bond) wires and then encased in a solid
epoxy lens. The architecture of the LED is shown in Fig.
Fig 4.7 LED Architecture

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4.1.7 Smoke Detector:
Fig 4.8 Smoke Detector
The H21A1, H21A2 and H21A3 consist of a gallium arsenide infrared emitting
diode coupled with a silicon phototransistor in a plastic housing. The packaging system is
designed to optimize the mechanical resolution, coupling efficiency, ambient light
rejection, cost and reliability. The gap in the housing provides a means of interrupting the
signal with an opaque material, switching the output from an “ON” to an “OFF” state.
Features:
• Opaque housing
• Low cost
• .035” apertures
• High IC(ON)
1. Derate power dissipation linearly 1.33 mW/°C above 25°C.
2. RMA flux is recommended.
3. Methanol or isopropyl alcohols are recommended as cleaning agents.
4. Soldering iron tip 1/16” (1.6mm) minimum from the housing.

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This sensor is used to detect any fire accidents. Whenever a fire accident occurs
some smoke is generated. This sensor detests that smoke and gives the response to the
microcontroller. The arrangement of this sensor in our sensor board is as shown below.
Fig 4.9 Arrangement of Sensor in Sensor Board
4.1.8 Node MCU:
NodeMCU is an open-source IoT platform. It includes firmware that runs on the
ESP8266 Wi-Fi SoC from Espressif Systems, and hardware which is based on the ESP-12
module. The term “NodeMCU” by default refers to the firmware rather than the DevKit.
The firmware uses the Lua scripting language. It is based on the eLua project and built on
the Espressif Non-OS SDK for ESP8266. It uses many open source projects, such as lua-
cjson, and spiffs.
Fig 4.10 Node MCU

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Specifications:
 Breadboard Friendly
 Light Weight and small size.
 3.3V operated, can be USB powered.
 Uses wireless protocol 802.11b/g/n.
 Built-in wireless connectivity capabilities.
 Built-in PCB antenna on the ESP-12E chip.
 Capable of PWM, I2C, SPI, UART, 1-wire, 1 analog pin.
 Uses a CP2102 USB Serial Communication interface module.
 Arduino IDE compatible (extension board manager required).
 Supports Lua (alike node.js) and Arduino C programming language.
Fig 4.11 Node MCU Pin Configuration

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Pin Functions:
Pin numbers in the Arduino IDE correspond directly to the ESP8266 GPIO pin
numbers. pinMode, digitalRead, and digitalWrite functions work as usual, so to read
GPIO2, call digitalRead(2) or its alias name digitalRead(D10).
At startup, pins are configured as INPUT. Digital pins 0-15 can
be INPUT, OUTPUT or INPUT_PULLUP. Pin 16 can
be INPUT, OUTPUT or INPUT_PULLDOWN_16 and is connected to the build-in LED.
It can be addressed with digitalRead(D0), digitalRead(16) or digitalRead
(LED_BUILDIN).
Pins may also serve other functions, like Serial, I2C, SPI. These functions are
normally activated by the corresponding library. The diagram above shows the pin
mapping for the popular ESP8266 NodeMcu module.
Pin interrupts are supported through attachInterrupt, functions. Interrupts may be
attached to any GPIO pin, except GPIO16. Standard Arduino interrupt types are
supported: CHANGE, RISING, FALLING.
Reserved Pins:
GPIO pins 6—11 are not shown on this diagram because they are used to connect
flash memory 'chips on most modules. Trying to use these pins as IOs will likely cause the
program to crash.
Note that some boards and modules (ESP-12ED, NodeMCU 1.0) also break out
pins 9 and 11. These may be used as IO if flash chip works in DIO mode (as opposed to
QIO, which is the default one).
Vin, 3V3, GND:
Vin is the NodeMcu's voltage input that is connected to its internal voltage regulator
allowing an input voltage range of 4.75V to10V. It will be regulated to 3.3V. Alternatively,
an external voltage source of 3.3V can be directly connected to the Node MCU's 3V3 pins.
The 3V3 pin can be also a voltage source to other components such as LEDs. GND is the
common ground of the board.

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Analog Input:
ESP8266 has a single ADC channel available to users. It may be used either to read
voltage at ADC pin or to read module supply voltage (VCC).
To read external voltage applied to ADC pin, use analogRead(A0).
The input voltage range is 0 — 1.0V.
To read VCC voltage, use ESP.getVcc() while the ADC pin must be kept
unconnected. Additionally, the following line has to be added to the sketch:
ADC_MODE(ADC_VCC);
This line has to appear outside of any functions, for instance right after
the #include lines of your sketch.
Analog Output:
analogWrite(pin, value) enables software PWM on the given pin. PWM may be
used on pins 0 to 16. Call analogWrite(pin,0) to disable PWM on the pin. the value may be
in the range from 0 to PWMRANGE, which is equal to 1023 by default. A value of 0, 512
and 1023 sets the PWM duty cycle to 0%, 50% and 100%, respectively. Optionally, the
PWM range may be changed by calling analogWriteRange(new_range).
PWM frequency is 1kHz by default. Call analogWriteFreq(new_frequency) to
change the frequency. The unit representation is in [Hz].
4.1.9 RF Module:
An RF module is a small size electronic device, that is used to transmit or receive
radio signals between two devices. The main application of the RF module is an embedded
system to communicate with another device wirelessly. This communication may be
accomplished through radio frequency communication. For various applications, the
medium of choice is radiofrequency since it does not need a line of sight. The applications
of RF modules mainly involve in low volume and medium volume products for consumer
applications like wireless alarm systems, garage door openers, smart sensor applications,
wireless home automation systems, and industrial remote controls.

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Main requirements for RF communication are:
 RF transmitter
 RF receiver
RF transmitter:
An RF transmitter module is a small size PCB capable of transferring a radio wave and
modulating radio waves to carry data. RF transmitter modules are usually applied along
with a microcontroller, which will offer data to the module which can be transmitted. These
transmitters are usually subject to controlling requirements that command the maximum
acceptable transmitter power o/p, band edge and harmonics requirements.
RF Receiver
An RF receiver module takes the modulated RF signal to demodulate it. There are two
kinds of RF receiver modules, namely the super-regenerative receivers and super-
heterodyne receivers. Usually, super-regenerative modules are low power designs and low
cost using a series of amplifiers to remove modulated data from a carrier wave. These
modules vary, generally inaccurate as their operation of a frequency significantly with
power supply voltage and temperature. The main advantage of Superheterodyne receiver
modules is a high performance over super-regenerative. They offer increased stability and
accuracy over a large temperature and voltage range. This stability comes from a stable
crystal design which in turn leads to a relatively more expensive product.
Fig 4.12 RF Transmitter & Receiver

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RF transceiver module is used in a particular device where both the transmitter and
receiver housed in a single module. Such devices transmit and receive RF signals, so that
is named as RF Transceiver. RF Transceiver module design is made up of amplifiers, RF
Mixers, pads & other RF components using microstrip technology. The transmitter and
Receiver parts in the RF transceivers called RF Upconverter and RF Downconverter.
Applications of RF Transceiver:
 RF transceiver module is used in wireless communication. The main application of
this transceiver is to make information in the form of data/voice/video apt to be
transmitted over the wireless medium.
 The main intention of this device is to alter IF frequency to RF frequency and vice
versa.
 RF transceiver module is used for radio transmission, satellite communication, for
television signal transmission, reception and in Wimax or WLAN, Zigbee or ITE
networks.

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CHAPTER 5
SOFTWARE DESCRIPTION
5.1 SOFTWARE COMPONENTS:
Software components involved in this project are:
1. Arduino IDE compiler
2. MIT app inventor
5.1.1 Arduino IDE compiler:
Arduino is an open-source electronics platform based on easy-to-use hardware and
software. Arduino boards can read inputs - light on a sensor, a finger on a button, or a
Twitter message - and turn it into an output - activating a motor, turning on an LED,
publishing something online. You can tell your board what to do by sending a set of
instructions to the microcontroller on the board. To do so you use the Arduino
programming language (based on Wiring), and the Arduino Software (IDE), based on
Processing.
Over the years Arduino has been the brain of thousands of projects, from everyday objects
to complex scientific instruments. A worldwide community of makers - students,
hobbyists, artists, programmers, and professionals - has gathered around this open-source
platform, their contributions have added up to an incredible amount of accessible
knowledge that can be of great help to novices and experts alike.
Arduino was born at the Ivrea Interaction Design Institute as an easy tool for fast
prototyping, aimed at students without a background in electronics and programming. As
soon as it reached a wider community, the Arduino board started changing to adapt to new
needs and challenges, differentiating its offer from simple 8-bit boards to products for IoT

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applications, wearable, 3D printing, and embedded environments. All Arduino boards are
completely open-source, empowering users to build them independently and eventually
adapt them to their particular needs. The software, too, is open-source, and it is growing
through the contributions of users worldwide.
Fig 5.1 Arduino IDE
Fig 5.2 Using Arduino IDE app

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The advantages of Arduino IDE application are
1. Inexpensive
2. The simple clear programming environment
3. extensible software and hardware
5.1.2 MIT App inventor:
MIT App Inventor lets you develop applications for Android phones using a web
browser and either the connected phone or an on-screen phone emulator. The MIT App
Inventor servers store your work and help you keep track of your projects.
Fig 5.3 Building blocks of MIT app inventor

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Fig 5.4 Architecture of MIT inventor app
You build apps by working with:
 The App Inventor Designer, where you select the components for your app.
 The App Inventor Blocks Editor, where you assemble program blocks that
specify how the components should behave. You assemble programs visually,
fitting pieces together like pieces of a puzzle.
Your app appears on the phone step-by-step as you add pieces to it, so you can test
your work as you build. If you don't have an Android phone, you can build your apps
using the Android emulator, software that runs on your computer and behaves just like
the phone.
The App Inventor development environment is supported for Mac OS X,
GNU/Linux, and Windows operating systems, and several popular Android phone
models. Applications created with App Inventor can be installed on any Android phone.

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Before you can use App Inventor, you need to set up your computer and install the App
Inventor.
Requirements to build an app:
1. Wi-Fi connection
2. Computer
3. Android device
To get the app:
1. It usually takes a few minutes to set up any app development environment. You
need not download anything to your computer.
2. On your phone or tablet, open the Google Play Store and find and install the MIT
AI2 Companion app. The Companion app is just an Android App that lets you test
the apps you build as you're building them.
3. Back in your computer's browser (Chrome, Firefox or Safari), open app inventor
by going to ai2.appinventor.mit.edu. Create a new project. The project name
should be typed without any spaces.
4. In the top menu, click on 'Connect' and 'Connect to Companion'. A QR code will
appear. Scan this QR code with the MIT AI2 Companion. The app should be seen
now.
Steps to build an android app:
Step 1: DESIGNER:: How your app looks
Step 2: BLOCKS:: How your app behaves
Step 3: TEST:: Testing while you are building
Step 4: BUILD:: Building your first app

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Step 1 : DESIGNER: How your app looks:
Design the App's User Interface by arranging both on- and off-screen components.
Fig 5.5 DESIGNER: How your app looks
Step 2: BLOCKS: How your app behaves:
Program the app's behaviour by putting blocks together.
Fig 5.6 BLOCKS: How your app behaves

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Step 3: TEST: Testing while you are building:
 MIT App Inventor Companion App
 Same Wi-fi
Fig 5.7 TEST: Testing while you are building
Step 4: BUILD:: Building your first app:
 Start new project, like project New, from scratch
 Import project (.aia-file) form a repository
 Gallery
 Import project (.aia-file) form my computer
 Export and share your app in an executable (.apk-file) form that can be installed
on a device
Required options are to be chosen to appropriate components used in the project.

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CHAPTER 6
WORKING PRINCIPLE
In this project, we used Arduino Uno ATMEGA 358 microcontroller to which a
2.4 GHz radio frequency wireless module has been serially attached. Using this, the system
will monitor light using a Light Dependent Sensor (LDR), humidity using the DHT11
sensor, smoke using MQ2 sensor and temperature using a temperature sensor. All the
sensor's values are continuously monitored and transmitted to the base station through the
RF module. This section will control the fan and light of the building based on the sensor's
threshold values.
On the base station, a NODE MCU ESP32 Wi-Fi Enabled controller is used and
connected to our mobile phone 4g hotspot. An RF module receiver is connected to the
serial to this module that will receive the data from the transmitter section and upload the
data to the server and can be used to control the devices. Using MIT App inventor an
android app is designed, which will connect to the central server that is used to view the
building parameters and also can control the light and fan from anywhere in the world
using IoT protocol.

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CHAPTER 7
PROJECT DESCRIPTION
This chapter explains how components are interfaced with each other using a schematic
diagram.
Fig 7.1 Schematic Diagram of the Transmitter

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Fig 7.2 Schematic Diagram of the Receiver

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CHAPTER 8
RESULT
In our project, we designed and implemented an application of building
automation with different sensors. All these sensor's values are continuously monitored
and transmitted from the main station to the base station. The base station prosses the
information received from the main station and uploads the data to the server.
Using MIT app inventor, we created an android app that is connected to the
central server and is used to view the building parameters and to control the light and fan
from anywhere.
Fig 8.1 Result

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Fig 8.2 Building Parameters in the Android App

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CHAPTER 9
ADVANTAGES AND APPLICATIONS
Any commercial building is expensive to operate and maintain. Heating, ventilation,
and air conditioning (HVAC), as well as lighting, make up 59% of commercial building
energy costs. Energy usage can be cut by 40% by using the latest, more advanced HVAC
and lighting controls. Thus, operating costs for older buildings can be lowered by
retrofitting equipment and controls. However, the cost of rewiring is often prohibitive.
That’s where wireless sensor networks (WSNs) can help. The further advantages are as
follows.
9.1 Advantages:
Fewer electricity bills:
As the amount of energy being consumed is reduced, the amount of electricity
associated with that energy consumed will also be decreased. This results in the saving of
both energy and electricity since the equipment is only operated when and where needed.
Easy Installation:
Adding a WSN to an existing building can lead to a double-digit percentage
decrease in operating costs over a period of years. Not only do energy costs decline
significantly, but wiring costs and hassles become a thing of the past.
Safety and Security:
Safety and security are the other benefits of a wireless sensor network. Wireless
sensor network systems are incredible in security, thereby ensuring the safety of the people
residing in the building.

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Comfort:
By more closely monitoring temperature, humidity, and ventilation, environmental
control helps improve comfort level depending on the number of people involved. One
study indicated a 3% increase in employee productivity when optimizing the comfort level.
9.2 Applications:
In a wireless sensor network, there are device sensors wirelesses capable of sending
information to another sensor device in a mesh network, however, most applications just
involve the delivery of data and information from each sensor device to a central data
collection point. Emerging wireless sensor technology promises to enable enhanced
conditions monitoring in and around buildings, not only because of the ease and the low
cost by which the sensors can be deployed, but also due to the true self-reconfiguration of
a system without any rewiring that becomes possible as ever didn’t before.
They play an important role in the flexibility and self-reconfiguration systems.
Wireless sensors could be placed on critical pieces of equipment in buildings to help detect
and diagnose faults. Some of the applications are listed below.
Fire/Smoke Detection and Alarm:
In hazardous situations such as fires, deployment of wireless sensors could provide more
information about the conditions within and around a building for first responders.
Energy Information Management:
An energy management information system (EMIS) is a performance management system
that enables individuals and organizations to plan, make decisions and take effective
actions to manage energy use and costs.

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Flood Management Assistance:
Sensors collect data from multiple sources such as rain gutters, sewer systems and pump
stations, to monitor fluctuations in water levels and water quality. If an alert triggers,
having a network camera in proximity to visually verify the situation helps responders
determine the best course of action.
Lighting systems:
Smart lighting is to cover the automation of lamp responses, such as dimming or on/off
control to enhance user comfort and save energy. An ambient light sensor (ALS) can be
used to detect the amount of natural light available, allowing a lamp's output to be adjusted
accordingly.
Parking Assistance:
Working in conjunction with weight sensors network cameras can count vehicles coming
into and leaving a lot or garage and verify when the facility has reached capacity. License
plate recognition and video analytics can be used to ascertain that a vehicle entering a
reserved parking space doesn’t match the credentials and vehicle attributes in the database.

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CHAPTER 10
CONCLUSION & FUTURE SCOPE
10.1 Conclusion:
This project demonstrated how wireless sensors and actuators can be integrated into
the existing Building Management System framework. An integrative architecture that can
be combined with legacy systems will allow the deployment of future systems, provided
that power for perimeter sensor nodes can be scavenged, or battery life extended into
multiple years, meaning that these networks will have to be rigorously energy efficient.
Our results are preliminary and further experimentation is required to successfully validate
our hypothesis of the benefit of using an ad hoc multiple sensor architecture that provides
a benefit of higher energy conservation and added thermal comfort.
10.2 Future Scope:
It is important that any further work in developing the technology core in the field of
sensor networks is done keeping in mind the potential users of these networks, and what
their needs are. This project is based on Wi-Fi but can be further continued by adding
advanced technologies like Zigbee and GSM. Low-power design should be the mantra at
all levels, be it hardware or software. Especially, in a field like BMS, where control and
monitoring networks already exist, any change in the status quo will only come about if
there are obvious benefits in bringing about the change.

38
REFERENCES
Websites:
www.arduino.cc
www.electronicshub.org
www.circuitdigest.com
ieeexplore.ieee.org
Books:
Automation Systems in Smart and Green Buildings (Modern Building Technology) by V
K Jain
Home Automation For Dummies by Dwight Spivey

39
APPENDIX
#include <SoftwareSerial.h>
SoftwareSerial mySerial(A0, A1); // RX, TX
#include "DHT.h"
float t;
float h;
int soilpin = 2;
int buzzerpin = 3;
int fanpin = 4;
int ldrpin = 5;
int ledpin = 6;
int motorpin = A4;
#define DHTPIN 7 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT 11
DHT dht(DHTPIN, DHTTYPE);
String incomingdata;
int ldrpinvalue;
int soilval;
int ledoperstatus;
int fanoperstatus;
int motoroperstatus;
int modeoperstatus;
String rtempraturevalue;

40
String rhumidvalue;
String rldrvalue;
String rsoilvalue;
String ledbitval;
String fanbitval;
String motorbitval;
String modebitval;
String soilvalue;
#include <SimpleTimer.h>
SimpleTimer updatetimer;
SimpleTimer sensorstimer;
void setup() {
Serial.begin(9600);
mySerial.begin(9600);
pinconfigs();
dht.begin();
updatetimer.setInterval(1000, udpate);
}
void loop() {
updatetimer.run();
sensormon();
temphumidcalc();
if (mySerial.available() > 0) {
incomingdata = mySerial.readString();
Serial.print("Read:"); Serial.println(incomingdata);

41
if (incomingdata.startsWith("*")) {
Serial.println("--- STAR LIGHT CAME");
incomingdata.remove(0, 1);
Serial.print("AFTER REMOVE UPDATE INCOMING DATA:");
Serial.println(incomingdata);
}
else if (incomingdata.startsWith("#")) {
Serial.print(" ASH CAME");
incomingdata.remove(0, 1);
Serial.print("AFTER REMOVE UPDATE INCOMING DATA:");
ledbitval = getValue(incomingdata, '/', 0); Serial.print(F("LIGHT VALUE : "));
Serial.println(ledbitval);
fanbitval = getValue(incomingdata, '/', 1); Serial.print(F("FAN VALUE : "));
Serial.println(fanbitval);
motorbitval = getValue(incomingdata, '/', 2); Serial.print(F("MOTOR VALUE :
")); Serial.println(motorbitval);
modebitval = getValue(incomingdata, '/', 3); Serial.print(F("MODE VALUE: "));
Serial.println(modebitval);
recvdata();
}
}
}
void udpate() {

42
Serial.println(F("### SENDING DATA TO NODEMCU ###"));
mySerial.print("#");
mySerial.print(rtempraturevalue);
mySerial.print("/");
mySerial.print(rhumidvalue);
mySerial.print(rsoilvalue);
mySerial.print(rldrvalue);
delay(500);
}
String getValue(String data, char separator, int index)
{
int found = 0;
int strIndex[] = { 0, -1 };
int maxIndex = data.length() - 1;
for (int i = 0; i <= maxIndex && found <= index; i++) {
if (data.charAt(i) == separator || i == maxIndex) {
found++;
strIndex[0] = strIndex[1] + 1;
strIndex[1] = (i == maxIndex) ? i + 1 : i;
}
}
return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
}

43
void pinconfigs() {
pinMode(fanpin, OUTPUT);
pinMode(ledpin, OUTPUT);
pinMode(buzzerpin, OUTPUT);
pinMode(soilpin, INPUT);
pinMode(ldrpin, INPUT_PULLUP);
digitalWrite(buzzerpin, 0);
digitalWrite(ledpin, 0);
digitalWrite(fanpin, 0);
}
void ledon() {
}
void ledoff() {
}
void fanon() {
}
void fanoff() {
}
void motoron() {
digitalWrite(motorpin, 1);
}

44
void motoroff() {
digitalWrite(motorpin, 0);
}
void buzzerpining() {
delay(1000);
}
void temphumidcalc() {
delay(2000);
h = dht.readHumidity();
t = dht.readTemperature();
if (isnan(h) || isnan(t) ) {
Serial.println(F("Failed to read from DHT sensor!"));
return;
}
// Serial.print(F("Humidity: "));
// Serial.print(h);
// Serial.print(F("% Temperature: "));
// Serial.print(t);
// Serial.print(F("°C "));
rtempraturevalue = String(t);
rhumidvalue = String(h);
Serial.println();

45
Serial.print(F("TEMPERATURE VALUE : ")); Serial.println(rtempraturevalue);
Serial.print(F("HUMIDITY VALUE : ")); Serial.println(rhumidvalue);
}
void sensormon() {
ldrpinvalue = digitalRead(ldrpin);
soilval = digitalRead(soilpin);
// Serial.print(F("----MOTION PIN : ")); Serial.println(ldrpinvalue);
// Serial.print(F("----LDR PIN : ")); Serial.println(ldrpinvalue);
if (ldrpinvalue == 1) {
rldrvalue = "LOW";
}
else {
rldrvalue = "HIGH";
}
if (soilval == 1) {
rsoilvalue = "DRY";
}
else {
rsoilvalue = "WET";
}
Serial.print(F("SOIL VALUE : ")); Serial.println(rsoilvalue);
Serial.print(F("LDR VALUE : ")); Serial.println(rldrvalue);
}
void recvdata() {

46
ledoperstatus = ledbitval.toInt();
fanoperstatus = fanbitval.toInt();
motoroperstatus = motorbitval.toInt();
modeoperstatus = modebitval.toInt();
Serial.println("+++++++++++++++++++++++++++++++++++");
Serial.print("LED INT:"); Serial.println(ledoperstatus);
Serial.print("FAN INT:"); Serial.println(fanoperstatus);
Serial.print("MOTOR INT:"); Serial.println(motoroperstatus);
Serial.print("MODE INT:"); Serial.println(modeoperstatus);
Serial.println("++++++++++++++++++++++++++++++++++++");
if (modeoperstatus == 0) {
Serial.println("**************** MANUAL MODE ********************");
if (ledoperstatus == 1) {
ledon();
}
else if (ledoperstatus == 0) {
ledoff();
}
if (fanoperstatus == 1) {
fanon();
}
else if (fanoperstatus == 0) {
fanoff();
}
if (motoroperstatus == 1) {
motoron();

47
}
else if (motoroperstatus == 0) {
motoroff();
}
}
else if (modeoperstatus == 1) {
Serial.println("**************** AUTO MODE ********************");
if (ldrpinvalue == 1) {
ledon();
}
else {
ledoff();
}
if (soilval == 1) {
motoron();
}
else {
motoroff();
}
if (t > 40) {
fanon();
}
else {
fanoff();
}
}
}

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