With Zigbee protocol, developed a distance measurement unit using an ultrasonic sensor, Arduino and X-bee trans-receiver for communication between displays and monitoring unit. Software used: Arduino

1. Distance Measuring Unit
Presented by:
Shanmugavel Ramani
Saima khan
Ankith kumar Hanumanthappa
Ashok Raj
Eshan gozarnoee
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2. Content:
2
• Introduction
• Aurdino board
• Zigbee
• X-ctu
• Ultrasonic Sensor
• Aurdino Software
• Program
• FT232RL Breakout Board
• Xbee Shield
• Result and Accuracy
• Conclusion

3. Project outline:
• Basically a unit which consists of ultrasonic sensor configured using a Arduino board.
• The sensors communicate using a Xbee trans-receiver which is also interconnected using the
Arduino board.
• The ultrasonic sensor here is used to detect objects and its distance from the measuring unit.
• The distance of the object is calculated using the basic principle of sonar where distance is
given by the formula
• Distance(d)=
𝟑𝟒𝟎.𝟐𝟖 𝒎/𝒔(𝒔𝒑𝒆𝒆𝒅 𝒐𝒇 𝒖𝒍𝒕𝒓𝒂𝒔𝒐𝒏𝒊𝒄 𝒔𝒐𝒖𝒏𝒅𝒊𝒏 𝒇𝒓𝒆𝒆 𝒔𝒑𝒂𝒄𝒆)∗𝒕𝒊𝒎𝒆 𝒕𝒂𝒌𝒆𝒏(𝑻)
𝟐
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4. FUNCTIONING OF THE SYSTEM: 4

5. ARDUINO BOARD:
 Description:
We used the Arduino PRO Wifi board! The board contains a WiFly RN-171 802.11b/g Serial
Module from Roving Networks connected to the Atmega328 through a SC16IS750 SPI-to-
UART chip.
The chip allows the RN-171 module to communicate with the atmega328 over the SPI bus
instead of the USART. By keeping the USART bus free, the board is able to communicate with
a PC using a standard USB to Serial Converter.
The Atmega328P is pre-flashed with the Arduino Pro bootloader running at 5V and 16Mhz;
which means it can be directly programmed with the Arduino IDE by just selecting Arduino
Pro 5v/16Mhz w/ Atmega328 during programming.
This board has the ability to server up a website, or act as a client to get information for the
world wide web! The possibilities are endless!
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6. SUMMARY :
Microcontroller ATmega328
Operating Voltage 3.3V or 5V
Input Voltage 5 - 12 V (5V versions)
Digital I/O Pins 14 (of which 6 provide PWM output)
Analog Input Pins 6
DC Current per I/O Pin 40 mA
Flash Memory
32KB (ATmega328) of which 2 KB used by
bootloader
SRAM 2 KB (ATmega328)
EEPROM 1 KB (ATmega328)
Clock Speed 16 MHz (5V versions)
Summary
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7. Memory
 The ATmega328 has 32 KB of flash memory for storing code (of which 2 KB is used for
the bootloader). It has 1 KB of SRAM and 512 bytes of EEPROM (which can be read and
written with the EEPROM library). The ATmega328 has 32 KB of flash, 2 KB of SRAM, and
1 KB of EEPROM
Communication
 The Arduino Pro has a number of facilities for communicating with a computer, another
Arduino, or other microcontrollers. The ATmega168 and ATmega328 provide UART TTL
serial communication, which is available on digital pins 0 (RX) and 1 (TX). The Arduino
software includes a serial monitor which allows simple textual data to be sent to and
from the Arduino board via a USB connection.
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8. Input and Output
 Each of the 14 digital pins on the Pro can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead()functions. They operate at 3.3 volts. Each pin
can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins have specialized
functions:
 Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the TX-0 and RX-1 pins of the six pin header.
 External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See
the attachInterrupt() function for details.
 PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.
 SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication, which, although provided by the underlying hardware, is not currently included in
the Arduino language.
 LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the LED is on, when the pin is LOW, it's off.
 The Pro has 6 analog inputs, each of which provide 10 bits of resolution (i.e. 1024 different values). By default they measure from ground to VCC, though is it possible
to change the upper end of their range using the AREF pin and some low-level code. Additionally, some pins have specialized functionality:
 I2C: 4 (SDA) and 5 (SCL). Support I2C (TWI) communication using the Wire library.
 There are a couple of other pins on the board:
 AREF. Reference voltage for the analog inputs. Used with analogReference().
 Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board.
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9. minimum number of connections –
power (3.3 V), ground, data in and data
out (UART), with other recommended
lines being Reset and Sleep. Additionally,
most XBee families have some other flow
control, I/O, A/D and indicator lines built
in. A version of the XBees called the
programmable XBee has an additional
onboard processor for user’s code. The
programmable XBee and a new surface
mount (SMT) version of the XBee radios
were both introduced in 2010.
XBee is the brand name from Digi International
for a family of form factor compatible radio
modules. The first XBee radios were introduced
under the MaxStream brand in 2005 and were
based on the 802.15.4-2003 standard designed
for point-to-point and star communications at
over-the-air baud rates of 250 kbit/s.
Two models were initially introduced a lower
cost 1 mW XBee and the higher power 100 mW
XBee-PRO. Since the initial introduction, a
number of new XBee radios have been
introduced and all XBees are now marketed
and sold under the Digi brand.
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12. What type of Modulation is used?
QPSK modulation is used for both XBee Series 1 and XBee-PRO series
1,however the emission designation is slightly different.
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13. Why QPSK?
QPSK uses two basis functions, a sine and a cosine whereas BPSK
uses just one. By varying the phase of each of these carriers we can
send two bits per each signal. The dimensionality of a modulation
is defined by the number of basis functions used . That make QPSK
a two dimensional signal . Not because it sends two bits per
symbol, but because it uses two independent signals (a sine and a
cosine) to create the symbols.
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17. 17

18. Ultrasonic Sensor:
1. How do humans sense distance?
Humans estimate distance using their eyes, which is usually not a
very accurate method.
2. How do bats sense distance?
Bats sense distance using sound. They emit sound waves and
receive back reflected waves. The time it takes to receive the waves
back provides them with a very good estimate of the distance. This
is exactly how ultrasonic sensors estimate distance.
3. Example for bats: calls made by mouth > ears hear reflected waves
> brain decides what to do > wing muscles move > flight path
changed, as needed. Bats use this same method to catch mosquitoes
too.
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19. Ultrasonic Sensor:
AN ULTRASONIC SENSOR HAS TWO PARTS:
• A TRANSMITTER THAT SENDS OUT A SIGNAL THAT HUMANS
CANNOT HEAR
• A RECEIVER THAT RECEIVES THE SIGNAL AFTER IT HAS BOUNCED
OFF NEARBY OBJECTS
THE SENSOR SENDS OUT ITS SIGNAL AND DETERMINES HOW LONG THE
SIGNAL TAKES TO COME BACK.
If the object is very close to the sensor, the signal comes back quickly
If the object is far away from the sensor, the signal takes longer to come back
If objects are too far away from the sensor, the signal takes so long to come back
(or is very weak when it comes back) .
The sensor sends a message back to the controller telling it the time taken for the
signal to return. Then it uses this info to compute how far away the object is.
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21. Echolocation
 Bats produce a very high-pitch sound (ultrasonic, beyond the human hearing
range greater than 20 KHZ). Those sound waves travel through air and bats
listen carefully to any echoes that return.
 By determining how long echoes take to return, bats estimate the distances of
the objects. Bats also determine how big objects are and in which direction
they are located. The bat brain processes the echoes similarly to human brains.
How does an ultrasonic sensor work?
 The ultrasonic sensor emits a sound pulse and measures the distance of the
object depending on the time taken by the echo to return back to the other
side.
 Electrical energy is converted to sound to send the pulse,
and then the sound received back is converted to electricity.
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22. How Can We Measure Distance?
The ultrasonic sensor sends out sound from one side and receives
sound reflected from an object on the other side.
The sensor uses the time it takes for the sound to come back from
the object in front to determine the distance of an object.
The “sonic” in ultrasonic refers to sound, and “ultra” means that
humans cannot hear it (but bats and dogs can hear those sounds).
The ultrasonic sensor can measure distances in centimeters and
inches. It can measure from 0 to 2.5 meters.
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23. Ultrasonic Sensor Application
Ultrasonic sensors have diversified functions including
 Detection
 Measurement
 Destruction
 Eye axis length
A probe applied to the surface of the cornea transmits an ultrasonic wave and receives the echo. From the
propagation time of the echo, the length of the eye axis (the distance between the surface of the eye (cornea) and
the back end of the eye (retina) = Diameter of the eyeball) can be determined.
 Cells
Applying ultrasonic energy into the human body will generate thermal energy, which causes a heating effect that
can destroy cells. This application is useful for treatment of cancer.
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24.  Level Measuring
Level measuring is used in a wide variety of applications. They
accurately monitor the fill level of silos or tanks used by dairies,
chemical plants, mineral companies, and many others.
 Vehicle detection in Barrier System
In car parking lots and parking garages, entry
is controlled using barrier systems. The barrier must not be
lowered when there is a vehicle underneath. Ultrasonic
sensors are particularly suitable for controlling this process.
 Spray Nozels
Using ultrasonic sensors can save on pesticides by detecting tree
gaps. As soon as one of these gaps is recognized, the spraying
process temporarily stops.
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25. Aurdino Software :
 The Arduino Integrated Development Environment (IDE) is a cross-platform application written
in Java.
 It easy to write code and upload it to the board.
 It includes a code editor with features such as syntax highlighting and brace matching
 Arduino programs are written in C or C++
 Users only need define two functions to make a runnable cyclic executive program:
 Setup()
 Loop()
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26. Program to find the Distance using sensor:
int Sig= 3;
void setup()
{
Serial.begin(9600);
}
void loop()
{
float dis;
int time;
pinMode(Sig,OUTPUT);
digitalWrite(Sig,HIGH);
delay(500);
digitalWrite(Sig,LOW);
pinMode(Sig,INPUT);
time= pulseIn(Sig,HIGH);
dis=(((time/2)*34.029)/1000));
Serial.write(dis);
Serial.print(" cm ");
Serial.print(‘n’);
delay(2000);
}
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27. FT232RL Breakout Board
 This is a breakout board also known as FTDI USB to UART IC (FT232RL)
 There are two options for communicating:
1) Virtual COM Port (VCP) drivers for RS-232 style serial ports.
• Virtual COM port (VCP) drivers cause the USB device to appear as
an additional COM port available to the PC
2) Special Dynamic Link Library (DLL) to directly control access to the USB
device and pin I/O
 Three LEDs telling you the status of RX (red), TX (green) and POWER (blue).
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28. FT232Rl Pin Description 28

29. FT232RL Breakout Board
Features:
• Implements full v2.0 USB protocol
• Needs no external crystal
• 14 I/O lines for use with RS-232, bit-bang, or special function modes
• Provides USB Bus power of 5V up to 500mA and regulated 3.3V up to 50mA
• Clock generator to drive microcontrollers (6, 12, 24, and 48 MHz)
• Easy logic level selection jumper
• All pins are labeled
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30. Bread board
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31. XBEE SHIELD 31

32. Significance of LED’S
LED LABEL LED COLOR OPERATIONS
PWR Red Power is present
DIO5 Green blinks when the XBee is associated with another
XBee.
DOUT Red Indicates wireless data is being received.
DIN Green Indicates wireless data is being transmitted.
RSSI Green
Indicates relative signal strength (RSSI) of last
received transmission.
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33. DIN and DOUT pins can be connected to either the UART pins
or any digital pin on the Arduino (D2 and D3 default)
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34. Result,Accuracy,Conclusion:
 We were able to find the distance between the Obstacle and Sensor
 Ultrasonic sensor is unable to measure the distance below 2cm
 The precision of the sensor is 2 cm to 2.6 metre under lab
condition
 We successfully transmitted the signal through Zigbee radio
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35. ANY QUERIES?
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37. Result and Accuracy:
 We were able to find the distance between the Obstacle and Sensor
 Ultrasonic sensor is unable to measure the distance below 2cm
 The precision of the sensor is 2 cm to 2.6 metre under lab
condition
 We successfully transmitted the signal through Zigbee radio
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38. Bibliography: 38
 www.wikipedia.com
 www.atmel.com
 Xp rf module
 Jconsystem1
 www.aurdino.com
 Building of WSN textbook