Visible light communication (sending data through light)

2
Acknowledgment:
This report could not be written to its fullest without [Doctor Jamal
Kharousheh], who served as my supervisor, as well as one who challenged and
encouraged me throughout my time spent studying under him. He would have
never accepted anything less than my best efforts, and for that, I thank him.
Also, we wish to thank everyone who helped us complete this dissertation.
Without their continued efforts and support, we would have not been able to
bring our work to a successfulcompletion. Dr. Mazen Rasekh and Dr. Falah
Mohammad.

3
Table of Contents (TOC)
Abstract………………………………………………………………….7
1. Introduction…………………………………………………………..8-01
1.1 statement of the problem……………………………………8
1.2 Motivation and Objectives………………………………..8
1.3 scope of the work …………………………………...........9
1.4 significance(importance) ……………………………..…..9-01
1.5 Organization of the Report…………………………….…01
2. Constraints and Standards……………………………………..00-16
2.1 Constraints………………………………………………00
2.2 Standards…………………………………………………00-12
2.3 Earlier course work…………………………………........12-16
3. Literature review………………………………………………17-21
3.1 The Visible Light Communication System Considered…..17
3.2 Traffic Light………………………………………………….18
3.3 Intelligent Transport System………………………………18-19
3.4 Visible Light Communication for Advanced Driver Assistant
Systems…………………………………………………………….19
3.5 Visible Light Communication Link for Video & Audio
Transmission……………………………………………………….21
4. Materials and Methods……………………………………………20-26
5. Results and Analysis……………………………………………….27-32
6. Discussion…………………………………………………………..33
7. Conclusions and Recommendations……………………………..34
7.1 Conclusions…………………………………………………34.
7.2 Recommendations…………………………………………..34
8. References………………………………………………………….35-36
9. Appendices………………………………………………………..37-53

4
List of Figures (LOC)
1. VLC system (Fig. 1.1)………………………………………………………………….8
2. VLC Advantages (Fig. 1.2)…………………………………………………………….9
3. How LED work (Fig. 2.1)………………………………………………………………13
4. Typical Led Characteristics (Fig. 2.2)………………………………………………….13
5. Phototransistor (Fig .2.3) ............................................................................…………….13
6. Arduino UNO pins (Fig.2.4) ……………………………………………………………14
7. Universal Serial Bus (USB) (Fig.2.5) …………………………………………………..14
8. 220 Ω resistor (Fig.2.6) ………………………………………………………………….15
9. 1 K Ω resistor (Fig.2.7) …………………………………………………………………15
10. Pin Configurations for opa847 (Fig.2.8)………..………………………………………15
11. Pin Configurations for opa358 (Fig.2.9) …………………….…………………………16
12. Arrangement of LEDs & receivers in an indoor system (Fig 3.1) ……………………17
13. Distribution of LEDs inside model room (Fig 3.2) ……………………………………17
14. Road-to-vehicle visible light communication (Figure 3.3)…………………………….. 18
15. Traffic lights and tail lights can be used as communication source (Fig3.4) ………….19
16. General architecture for a full duplex VLC system (Figure 3.5) ………………………19
17. Block diagram of real-time video/audio VLC transmission system (Fig.3.6) …………21
18. The VLC circuit (Fig.4.1)………………………………………………………………20
19. Experimental circuit (Fig.4.2)…………………………………………………………...22
20. The final transmitter circuit (Fig4.3)……………….……………………………………23
21. The final receiver circuit (Fig.4.4)………………………………………………………24
22. Transmitter application (Fig4.5)………………………………………………………..24
23. Receiver application (Fig.4.6)…………………………………………………………24
24. The Flowchart (Fig.4.7)……………………………………………………………….25
25. Testing result (Fig.5.1)…………………………………………………………………28

5
26. Transmission and Reception operations (Fig.5.2)…………………………………….29
27. Selecting Image (Fig.5.3)…………………………………………………………….31
28. Show receiving image (Fig.5.4)………………………………………………………30
29. Distance testing (Fig.5.5)……………………………………………………………..32

6
List of Tables (LOT)
Table 1: Comparison between VLC System and other Communication systems……....27
Table 2: Comparison between VLC System and RF ……………………..…………….28
Table 3: The Voltage at Photo transistor………………………………………...………29

7
Abstract:
The increase of mobile applications using radio frequencies (RFs) has
highlighted concerns about the adequate availability of RF bands and the limits
of transmission capacity in mobile telecom networks, as well as the data
security issues involved. Visible Light Communication (VLC) technology is
used as a medium for data transmission which is one of the most advanced
optical wireless communication technologies, in which light in the visible
region (375nm-780nm). This technology is more secure and achieves high data
rates as compared to conventional wireless technologies.

8
Chapter 1: Introduction
1.1 statement of the problem
Nowadays people are using several types of communication system such as
infrared, radio communication, Bluetooth …… etc. these types face some
problems including limited transmission power, security, limited data rates
…etc. in our project we are developing a new communication system that will
solve almost all these problem. This system is called visible light
communication.
Visible Light Communication (VLC): is free space optical communication,
and line of sight (LOS) is the common link between two points in optical
wireless communication system, where the transmitter directs the visible light
beam in a straight and unobstructed path to the receiver [1]. In this technology
LEDs are used as transmitter, the Air as a transmission medium and the
Photodiodes as a receiver.
Fig.1.1 VLC system. [2]
1.2 Motivation and Objectives
From our review of the literature, it became evident that work should be done to
look into the possibility of designing a new model that could fit the present
infrastructure for indoor applications [3]. Therefore, the objectives of the
research presented in this thesis can be summarized as follows:
 Build a circuit for VLC by using LED to LED.
 Test the circuit then take notes and discus the performance.

9
 Suggest a guideline for the design and implementation of future
development of the prototypes.
1.3 Scope of the work
we hope that the achievement of this project in reality will make everyone in
everywhere and at all times be able to send and receive text, image, audio and
video with lowest cost, reasonable rate and more security without using the
internet.
1.4 Significance (importance)
VLC Advantages:
Fig.1.2 VLC Advantages [4]
VLC System has many advantages over the other Communication Systems:
1- Security: VLC is use light communication and it's visible so in this case
it's easy to determine who can receive the message and it's impossible to
tap the communication without breaking the link.
2- Human Safety: VLC doesn't effect at the human body. Thus, the
transmission power can be kept high if needed.

10
3- Bandwidth: VLC has a bandwidth range from 430 THz to 750 THz and
this range is larger than the bandwidth in the RF Communications from 3
kHz to 300 GHz.
4- High Data Rates.
5- Unlicensed Spectrum: No company owns property rights for visible
light and thus no royalty fees have to be paid nor does expensive patent-
license have to be purchased in order to use visible light for
communication purposes [5].
6- Ubiquitous Nature: visible light is present in many places, so there is the
opportunity to combine light communication with lighting design to let
Visible Light Communication (VLC) coexist with the lighting setup
present in many offices, homes, or institutions.
1.5: Organization of the Report
Chapter 1 of this thesis serves to provide an overview of the basic concepts and
techniques in physics and engineering and also shows several designs that are
required for the implementation of VLC. Chapter 2 provides the constraints,
standards /codes and earlier course work. Chapter 3 literature review. Chapter 4
methodology .Chapter 5 results and analysis. Chapter 6 discussion the results.
Chapter 7 presents recommendations for improving the designs, as well as the
conclusion with suggestions for further improvements in the work.

11
Chapter 2:
2.1Constraints
The main problem was with dealing with the Arduino Where we encountered a
problem in writing the code. Also we had two problems with the hardware
circuit. The first one is LOS Communication which means that we need line
of sight communication. The second problem was the short Range i.e. this
technology usually works over a short distance range. Also we faced many
other problems such as:
1. Important elements of the circuit were unavailable in Palestine so we had
to order them from other countries. They took a lot of time to be available
in our hands and thus there was a very short time for the implementation
of the circuit.
2. The size of the elements is very small, so we needed special equipments
for the implementation.
3. Part of the project needed new software which required us to learn a new
software programs.
2.2Standards
 the Visible Light Communication Consortium was established
in 2003 by Japanese tech-companies
 aims to standardize VLC technology
 avoid fragmentation of different protocols and implementations
 two standards are proposed:
 JEITA CP-1221
 JEITA CP-1222
 also tries to raise public awareness for VLC and promote its
applications
 Standardization efforts for physical and media access layer are
also done by IEEE 802.15, Task Group 7.
 in 2007, the VLCC proposedtwo different standards:
 Visible Light Communication System Standard
 Visible Light ID System Standard
 JEITA (Japan Electronics and Information Technology
Industries Association) accepted these standards as JEITA
CP-1221 and JEITA CP-1222

12
JEITA CP-1221 (1/2)
 motivation:
 avoid fragmentation and proprietary protocols
 prevent interference
 light that is used for communication purposes must be within a
range of 380nm to 750nm emitted light must be within a particular range
with an accuracy of 1nm sub-carrier (SC) modulation is proposed (as
opposedto modulating the frequency of the actual light)
JEITA CP-1221 (2/2)
 there are three major frequency ranges:
 range 1 (15 kHz to 40 kHz):
- communication purposes
 range 2 (40kHz to 1 MHz):
- fluorescent lights cannot use this range
- they are too slow and generate too much noise
 range 3 (> 1 MHz):
- should only be used for vast data transmission with special LEDs19
JEITA CP-1222
 according to Shinichiro Haruyama (vice chairman of the VLCC)
the following recommendations are proposedbyJEITA CP-1222 :
 SC frequency: 28.8 kHz
 transmission rate: 4.8 kbps
 modulation: SC-4PPM(chosen to avoid flickering)
 cyclic redundancy checks (CRC) for error detection/correction .[5]
2.3 Earlier Coursework
In this project we made use in some subjects such as electronic, digital
communication,……. Etc.

13
*Light Emitting Diode (LED)
Fig.2.1 How LED work [6] Fig.2.2 Typical Led Characteristics [7]
*Phototransistor:
the st-1kla is a high-sensitivity phototransistor mounted in durable ,
hermetically sealed TO-18 metal can which provide years of reliable
performance even under demanding conditions such as use outdoors. It has two
leads. It can be used in various applications such as smoke detectors, infrared
sensor, optical switches and optical detectors. [8]
Fig .2.3 Phototransistor [9]

14
*Arduino UNO
Fig.2.4 Arduino UNO pins [10]
The Arduino Uno is a microcontroller board based on the ATmega328. It has 14
digital input/output pins (of which 6 can be used as PWM outputs), 6 analog
inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP
header, and a reset button. It contains everything needed to supportthe
microcontroller; simply connectit to a computer with a USB cable or power it
with an AC-to-DC adapter or battery to get started. The Uno differs from all
preceding boards in that it does not use the FTDI USB-to-serial driver [11]
* Universal Serial Bus (USB)
Used to communicate via the USB protocol with a host computer (for
programming or sending/receiving serial data).
Fig.2.5 Universal Serial Bus (USB)

15
*Resistors:
Resistor is an electrical component that reduces the electric current.
The resistor's ability to reduce the current is called resistance and is measured in
units of ohms (symbol: Ω).
Fig.2.6 220 Ω resistor Fig.2.7 1 K Ω resistor

16
OPA847
Fig.2.8 Pin Configurations for opa847 [12].
OPA358:
Fig.2.9 Pin Configurations for opa358 [13]

17
Chapter 3 Literature Review
This chapter provides an overview of the topics that supplied the ideas for this
report and the following sections examine the previous works which have been
done on implementing Visible Light Communication technology.
3.1 The Visible Light Communication System Considered
Fig 3.1: Arrangement of LEDs & receivers
In an indoor system [14]. Fig 3.2: Distribution of LEDs
Inside model room [14].
The final objective of VLC development is the application of off-the-shelf
LEDs in home environment wireless network to satisfy the needs of both
illumination and data transmission. An indoor visible light communication
system using white LEDs under consideration is shown in Fig. 3.1& 3.2[14].
All the lights in the room are replaced by LEDs. The LEDs are not only used for
illuminating the room but also for an optical wireless communication system.

18
3.2 Traffic Lights
Figure 3.3: Road-to-vehicle visible light communication [15].
The above Fig. 3.3 shows the basic usage of LED as a transmitter and
CAMERA as a Receiver. In this model, they mounted a camera before the front
end of the car. The Camera is used as the information receiver from traffic
signal lights. The advantage of using the camera is that multiple data can be
transmitted by the LEDs and received by High-speed cameras [15].
3.3Intelligent Transport System
This technology can be used to design an intelligent transport system to ensure
road safety. Nowadays, solid state lighting is widely used in traffic signals and
vehicle lights. So, these sources can also be used for both car-to-car and car-to-
traffic signal information communication.

19
Fig3.4 Traffic lights and tail lights can be used as communication source [16].
For instance it has been proposed a traffic light can be used to transmit the time
for which it would remain yellow to the vehicles as far as 50m away .In addition
to it, car –to car communication can be used for data logging at the time of
accident. This information can be used to investigate the nature of the accident
[16].
3.4 Visible Light Communication for Advanced Driver
Assistant Systems
Figure 3.5: General architecture for a full duplex VLC system [3].
Optical communications for outdoor communication has been discussed and
elaborated upon. Devices such as laptops and mobile phones can be used for
transmitting and receiving information, using transceivers, as shown in Fig. 3.5.
Transceiver systems use both LEDs and photodiodes. Intensity modulation was
implemented to reach the most viable modulation. Various important design
parameters were optimized by using intensive investigation based on gain
variation over 100m of transmission range [3].

20
3.5 Visible Light Communication Link for Video & Audio
Transmission
Fig.3.6 Block diagram of real-time video/audio VLC transmission system [1].
Video and audio signal captured by video camera are amplified by a self-
designed amplifier and then superimposed onto two LED lamps. Thus, the
output light rays changes in intensity corresponding to the variation in signal,
which however is insensitive to human eyes due to the rapid frequency response
of LED devices. The distance between two LEDs was about 10 cm in order to
avoid mutual interference caused by light sources. At the receiver, two highly
sensitive photodiodes are used to detect light transmitted over two separate
optical channels. And the directionality of the PDs is required to be aligned with
the most intense portion of the emitted light beams. After detection, optical
signals are converted into photo electric current proportional to the variation of
incident light which then is amplified and filtered by a low pass filter (LPF) [1].

21
Chapter 4 Materials and Methods
4.1 Designof VLC Prototype
Fig 4.1 The VLC circuit
VLC is typically implemented using white LED light bulbs at the transmitter.
These devices are normally used for illumination only by applying a constant
current. However, by fast and subtle variations of the current, the optical output
can be made to vary at extremely high speeds. This very property of optical
current is used in VLC setup. The operational procedure is very simple, if the
LED is on, you transmit a digital 1, if it’s off you transmit a 0. The LEDs can be
switched on and off very quickly, which gives nice opportunities for
transmitting data. Hence all that is required is some LEDs and an Arduino that
code data into those LEDs. All one has to do is to vary the rate at which the
LED’s flicker depending upon the data we want to encode. Further
enhancements can be made in this method, like using an array of LEDs for
parallel data transmission to transmit larger data like, videos, audios and
pictures.

22
After building the previous circuit that shown in Fig.4.1 and sending a message
from 5cm distance between the transmitter and receiver circuits we worked to
improve our VLC system in order to increase the distance and to send more
types of data in addition to the message such as images and voice.
At first, we tried to build the circuit shown in fig.4.2 but unfortunately it didn’t
work as we wanted.
Fig.4.2 Experimental circuit
Because of that we tried other ways to make the distance larger as:
1. Changing resistors values in the transmitter and receiver circuits and put
instead of old ones smaller values. So we put a 60Ω resistor at the
transmitter circuit and 20Ω resistor at the receiver circuit.
This increased the distance from 5cm to 30cm.
2. Put two convex lenses, one (30cm focal length) after the white LED and the
other (taken from car) before the photo transistor.
And this way increased the distance between the transmitter and the receiver
to 1.6m.

23
The final circuits that we achieved are shown in the figure below:
1. The final transmitter circuit :
We put the LED in the center of the convex lens to be sure that we use
all the light.
Fig4.3 The final transmitter circuit

24
2. The final receiver circuit:
The distance between the photo transistor and the convex lens is 15cm and we
chooseit after testing many distances.
Fig4.4 The final receiver circuit
4.2 Software Design
In order to send more data such as, images we designed a new applications
(transmitter and Receiver) using C sharp programme.
The figures below show the two applications:
Fig4.5 Transmitter application Fig4.6 Receiverapplication

25
4.3 Flow Chart
Fig 4.7 the Flowchart
Arduino
We used it to convert the input data into bits in order to transmit it into the LED.
Resistors
To protect the LED and Phototransistor from the high current.
LED:
It modulates the Bits received from the Arduino by converts the electrical
current into light pulses
Start
Insert Data to
Arduino
Bits are
modulated
inside the LED
Light pulses will
transmitted
through the light
Photo transistor
will receive the light
pulses
Light pulses will be
demodulated inside the
photo transistor
the Arduino will receive
the Bits
Bits will be converted
to sinusoidal signal
Convert data
into bits
End
TransmitterReceiver

26
Why we used LEDs ?
With LEDs, it is possible to control light brightness at a frequency much higher
than conventional light bulbs: LEDs can be switched on and off at very high
rates. As result, LED-based lighting can be used for wireless communication
services by modulating the intensity of the emitted light. Further, LEDs can also
be used as receivers just like photodiodes. We call this concept Visible Light
Communication (VLC) with LED-to-LED networking [17].
Phototransistor
In order for data transmission to have any significance there must be a way to
receive the signal at the other end of the design. This is the purpose of the
photodiodes as they react to the light emitted from the LEDs and allow for
current to flow to the rest of the receiver circuit. When there is no light emitted
from the LEDs the photodiodes do not allow current to flow through to the
Arduino on the receiver.
USB
It used to transmit the data from the device to Arduino.

27
Chapter 5 Results
After research we found that the VLC system is different from the other
Communication systems and we summarize these differences in the following
tables:
GPS RFID WIFI QR code Visible light
communication
Position
accuracy
Several
meters
Several
millimeters
to Several
meters
Several
meters to
Several
hundred
meters
Several
millimeters
to Several
meters
Several meters
Measurement
time
A few
minutes
Less than a
second
Several
seconds
Several
seconds
Less than a
seconds
Measurement
device
GPS
receiver
RFID reader WIFI
transceiver
Image
sensor
Visible light
receiver
Database Not
necessary
necessary necessary necessary Not necessary
The use of
indoor and
underground
impossible possible possible possible possible
Recognition
of building
floors
Impossible possible difficult possible possible
Applications Outdoor Inoutdoor Inoutdoor Inoutdoor Inoutdoor
Possibility of
widespread
use
Already
widely used
for outdoor
Need to
install RFID
tags all over
the place
Need to
install WIFI
base
stations all
over the
place
Need to
install QR
code
stickers all
over the
place
Need to install
Visible light
transmitters all
over the place
illumination
lights can be
used as
transmitter
Table 2: Comparison Between VLC System and other Communication system.

28
RFVLCProperty
NOYesVisibility
850-950nm400THZ-790THZFrequency
1-2 mb/s3.25 Gb/sData rate
Less comp. to VLCMoreSecurity
MediumRelative lowPower Consumption
MediumShortCoverage Distance
YesNOHarmless for human
body
Table 3: Comparison Between VLC System and RF.
After building the basic circuit of the VLC system we test it by connectthe
receiver to an oscilloscope and got the following result:
Fig.5.1 testing result

29
This result mean that the message was sent from the transmitter should be the
same at the receiver in order to make sure that the phototransistor receives data
from the LED.
Next, a measurement was made on the voltage at several distances in order to
know at what distance the receiver (phototransistor) will not receive any data
from the transmitter (LED). The results are showed in the following table:
Output Voltage (p)Distance
400 mv2cm
178 mv4cm
Table 1: The Voltage at Photo transistor
After measuring the voltage, the codewas downloaded into the arduino and a
text message was inserted into it then the transmission operation begun. The
photo below shows transmission and reception operations
Fig.5.2 Transmission and Reception operations

30
As we mentioned earlier we tried to send other types of data like images by
writing C# code.
The result we got is shown in the figures below:
Fig.5.3 Selecting Image

31
Fig.5.4 Show Receiving Image
Then after increasing the distance we test the circuit and we succeed to send
messages from 1.6m distance

33
Chapter6 Discussion
At the beginning of our project we hoped (or expected) that we will be able to
send and receive data through light with relatively high data rate and at
acceptable distance (at first we looked forward to send and receive data at least
at 3 meters). on one hand, we succeeded to send receive the data. But on the
other hand, there was a problem in the distance, i.e. the highest distance the
receiver was able to receive data from the transmitter with relatively low error is
5 cm. There were two suggested problems; the first problem is that the LED
needed relatively high power in order to send the data to high distance, the
second problem is that the light distract along high distances.
We solved these two problems by decreasing the resistors values in the
transmitter and receiver circuits and by adding two convex lenses after the white
LED and before the photo transistor.

34
Chapter7: Conclusion and Recommendation
At the end of this project we were able to send and receive text message through
led-to-led communication. This proved that at the future we will be able to send
and receive any kind of data using every light bulb everywhere like the Wi-Fi
hotspots.
In the future we hope to send and receive all kind of data such as video and
audio. In addition, we hope to have mobile-to-mobile communication instead of
computer-to-computer communication.

35
References
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[7] expertsmind, Light Emitting Diode Colors. [Online]Available from:
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[Last Access: 27th, November, 2014].
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[12] alldatasheet, Wideband, Ultra-Low Noise, Voltage-Feedback

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OPERATIONAL AMPLIFIER with Shutdown. [Online]Available from:
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38
Appendix A
Arduino Codes
Testing Code:
Transmitter code:
void setup()
{
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
// Clear Timer on Compare Match (CTC) Mode
bitWrite(TCCR1A, WGM10, 0);
bitWrite(TCCR1B, WGM12, 1);
// Toggle OC1A and OC1B on Compare Match.
bitWrite(TCCR1A, COM1A0, 1);
bitWrite(TCCR1A, COM1B0, 1);
// No prescaling
bitWrite(TCCR1B, CS10, 1);
OCR1A = 210;
OCR1B = 210;

39
Serial.begin(2400);
}
void loop()
{
Serial.println("testing testing testing");
delay(500);
}
Receivercode:
void setup()
{
Serial.begin(2400);
}
void loop()
{
// if incoming serial
if (Serial.available()) {
readSerial();
digitalWrite(13, HIGH);
} else {
digitalWrite(13, LOW);
}
delay(10);
}

40
void readSerial() {
char val = Serial.read();
Serial.print(val);
}

41
The final Code for Arduino:
Transmitter code:
#include <SoftwareSerial.h>
SoftwareSerial altSerial(2, 3); // RX, TX
//generates 38kHz carrier wave on pin 9 and 10
//sends data via TX every 500ms
void setup()
{
Serial.begin(2400);
altSerial.begin(2400);
pinMode(9, OUTPUT);
// Clear Timer on Compare Match (CTC) Mode
// Toggle OC1A and OC1B on Compare Match.

42
// No prescaling
OCR1A = 210;
OCR1B = 210;
}
void loop()
{
char c;
c = Serial.read();
altSerial.print(c);
altSerial.flush();
Serial.flush();
}
if (altSerial.available()) {
c = altSerial.read();
Serial.print(c);
}
}

43
Receiver code:
void setup()
{
Serial.begin(2400);
Serial.flush();
}
void loop()
{
// if incoming serial
readSerial();
// Serial.flush();
digitalWrite(13, HIGH);
} else {
// Serial.flush();
digitalWrite(13, LOW);
}
delay(2);
}
void readSerial() {
char val = Serial.read();
Serial.flush();
Serial.print(val);
}

44
Appendix B
C Sharp Code:
Transmitter Application code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.IO.Ports;
namespace CSharpEasySerial
{
public partial class frmSerial : Form
{
public string strFileName = "";
public static System.IO.Ports.SerialPort serialPort1;
private delegate void LineReceivedEvent(string line);
System.IO.FileStream _FileStream = new System.IO.FileStream("c:rcrc.txt",
System.IO.FileMode.Append, System.IO.FileAccess.Write);
public frmSerial()
{
InitializeComponent();

45
}
private void btnConnect_Click(object sender, EventArgs e)
{
System.ComponentModel.IContainer components = new
System.ComponentModel.Container();
serialPort1 = new System.IO.Ports.SerialPort(components); // Creating the new
object.
serialPort1.DataReceived += serialPort1_DataReceived;
serialPort1.PortName = "COM" + numCom.Value.ToString(); // Setting what port
number.
serialPort1.BaudRate = 2400; // Setting baudrate.
serialPort1.DtrEnable = true; // Enable the Data Terminal Ready
serialPort1.Open(); // Open the port for use.
btnConnect.Text = "Connected.";
btnConnect.Enabled = false;
numCom.Enabled = false;
}
private void btnSend_Click(object sender, EventArgs e)
{
try {
// Sends the text as a byte.
// serialPort1.Write(new byte[] { Convert.ToByte(txtDatasend.Text) }, 0, 1);
byte[] bytes = System.IO.File.ReadAllBytes(strFileName);
serialPort1.Write(bytes, 0, bytes.Length );

46
lblSucceed.Visible = true;
}
catch( Exception exc){
Console.WriteLine("Exception caught in process: {0}", exc.ToString());
}
}
private void btnSelect_Click(object sender, EventArgs e)
{
lblSucceed.Visible = false;
OpenFileDialog fd = new OpenFileDialog();
// string strFileName = null;
fd.Title = "Open File Dialog";
fd.InitialDirectory = "C:";
fd.Filter = "All files (*.*)|*.*|All files (*.*)|*.*";
fd.FilterIndex = 2;
fd.RestoreDirectory = true;
if (fd.ShowDialog() == DialogResult.OK)
{
strFileName = fd.FileName;
lblFileName.Text = lblFileName.Text + strFileName;
}
}

47
private void serialPort1_DataReceived(object sender,
System.IO.Ports.SerialDataReceivedEventArgs e)
{
int bytes = serialPort1.BytesToRead;
byte[] buffer = new byte[bytes];
serialPort1.Read(buffer, 0, bytes);
ByteArrayToFile("c:rcrc.txt", buffer);
//RxString = serialPort1.ReadExisting();
//this.Invoke(new EventHandler(DisplayText));
}
public bool ByteArrayToFile(string _FileName, byte[] _ByteArray)
{
try
{
// Open file for reading
// Writes a block of bytes to this stream using data from a byte array.
_FileStream.Write(_ByteArray,0, _ByteArray.Length);
// close file stream
_FileStream.Close();
return true;

48
}
catch (Exception _Exception)
{
// Error
Console.WriteLine("Exception caught in process: {0}", _Exception.ToString());
}
// error occured, return false
return false;
}
private void frmSerial_FormClosing(object sender, FormClosingEventArgs e)
{
if (serialPort1.IsOpen) serialPort1.Close();
}
}
}

49
Receiver application code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
namespace SimpleSerial
{
public partial class Form1 : Form
{
// Add this variable
System.IO.FileStream _FileStream = new System.IO.FileStream("c:rcrc.txt",
System.IO.FileMode.Append, System.IO.FileAccess.Write);
public Form1()
{
InitializeComponent();
serialPort1.DataReceived += serialPort1_DataReceived;
}
private void buttonStart_Click(object sender, EventArgs e)
{
serialPort1.PortName = "COM" + textBox2.Text ;

50
serialPort1.BaudRate = 2400;
serialPort1.Open();
if (serialPort1.IsOpen)
{
buttonStart.Enabled = false;
buttonStop.Enabled = true;
// textBox1.ReadOnly = false;
}
}
private void buttonStop_Click(object sender, EventArgs e)
{
if (serialPort1.IsOpen)
{
serialPort1.Close();
buttonStart.Enabled = true;
buttonStop.Enabled = false;
//textBox1.ReadOnly = true;
}
}
//private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
//{
// // If the port is closed, don't try to send a character.
// if (!serialPort1.IsOpen) return;

51
// // If the port is Open, declare a char[] array with one element.
// char[] buff = new char[1];
// // Load element 0 with the key character.
// buff[0] = e.KeyChar;
// // Send the one character buffer.
// serialPort1.Write(buff, 0, 1);
// // Set the KeyPress event as handled so the character won't
// // display locally. If you want it to display, omit the next line.
// e.Handled = true;
//}
private void DisplayText(object sender, EventArgs e)
{
// textBox1.AppendText(RxString);
}
private void serialPort1_DataReceived(object sender,
System.IO.Ports.SerialDataReceivedEventArgs e)
{
int bytes = serialPort1.BytesToRead;
byte[] buffer = new byte[bytes];
serialPort1.Read(buffer, 0, bytes);
ByteArrayToFile("c:rcrc.txt", buffer);

52
//RxString = serialPort1.ReadExisting();
//this.Invoke(new EventHandler(DisplayText));
}
public bool ByteArrayToFile(string _FileName, byte[] _ByteArray)
{
try
{
// Open file for reading
// Writes a block of bytes to this stream using data from a byte array.
_FileStream.Write(_ByteArray, 0, _ByteArray.Length);
// close file stream
_FileStream.Close();
lblfileRec.Text = "File Received";
return true;
}
catch (Exception _Exception)
{
// Error
Console.WriteLine("Exception caught in process: {0}", _Exception.ToString());
}
// error occured, return false
return false;

53
}
private void button1_Click(object sender, EventArgs e)
{
MemoryStream stream = new MemoryStream(File.ReadAllBytes(@"c:rcrc.txt"));
Image image = Image.FromStream(stream);
this.pictureBox1.Image = image;
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (this.serialPort1.IsOpen)
{
this.serialPort1.Close();
}
}
}
}

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