kertas kerja seminar 2

8/4/2019 Kertas Kerja Seminar 2

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1.0 Abstract

Objects Location Tracking using Walkie-Talkie and Triangulation method is a

system which was designed to track location of an object in confines areas instead ofusing GPS (Global Positioning System). The project have four main objectives which are

to determine the appropriate triangulation formula, to find the relation of signal strength

sent from transmitter to the receiver with distance, to build a model to establish

triangulation method and lastly to display objects location using the LabVIEW

(Laboratory Virtual Instrumentation Engineering Workbench) software. The project

development was divided into two parts which are hardware implementation and

software development. For hardware implementation, a walkie-talkie was used

(Motorola P200) as transmitter (object) and three others as receivers, to determine the

triangulation area. By using triangulation method formula, the output from the receivers

was the input to the software development. For software development, LabVIEW was

being chosen for this project because of the software compatible with the hardware part.

Using C and graphical programming by LabVIEW, the object can be tracked and its

location automatically displayed on the monitor of personal computer.


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2.0 Methodology

For PSM 2, the methodologies continue with the hardware implementation and

software development. For hardware implementation as shown in Figure 4(a), the main

component is the four walkie-talkies (1 walkie-talkie acts as transmitter (object) and the

rest acts as receivers), National Instruments BNC-2110 and DAQ Card. At the top of the

receivers walkie-talkies, there is universal connector, [3]. The universal connector was

connected to the BNC-2110 by using CAT5 and crocodiles clips. The output of the

receivers walkie-talkies is voltage.

The test at the laboratory was done to identify which pins are suitable to get the

output voltage of the receiver. By using Pin 6(DATA) and Pin 5(GROUND), the

experiment is to test the effects of the output voltages of the walkie-talkies when placed

near and far to each other.

The results were as follows:

Table 1 Data from the oscilloscope.

Parameter Near Far

Vpp (mV) 832 672Time(ms) 19.94 20.04

Cycle RMS(mV) 268 211

Frequency(Hz) 50.15 49.90

Volt/div = 1V/division

Time/div = 5ms/division

Figure 1 Sine output

voltage of the receivers

walkie-talkie.


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From the test, when both walkie-talkies were placed near to each other, the output

voltage is higher than the further ones. So, Pin 6 is suitable to this project for finding the

output voltages.

Another test was assigned to know the voltages whether it proportional or not due

to the distances of the walkie-talkies. The results were as follows:

Table 2 Data from multimeter.

Distance(m)

Voltage(mV)

0 42.6

1 35.6

2 30.0

3 25.74 20.8

5 15.1

6 10.0

7 6.3

8 2.5

9 0.5

10 0.2

From this experiment, the voltages decreased proportionally to the increase of the

distances. Then, the graph is linear as Figure 2.


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Figure 2 Graph voltages (mV) versus distances (m).

Last step to the hardware implementation is to arrange the walkie-talkies based on

triangulation. The walkie-talkies were placed as Figure 3.

Figure 3 Walkie-Talkies were placed in triangulation position.

The locations of the receivers were fixed as below (in meter). Only the objectwas adjusted.

R1 = (0, 0)

R2 = (2.5, 5)

R3 = (5, 0)

For software part as Figure 4(b), there are three subparts programming using

LabVIEW. First subpart programming is to show the waveform and display the values of

output voltages from the receivers. Second is to display the values of the conversion of

the output voltages to signal strength in decibel. Last programming is to display the

location of the object.


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Figure 4(a) The flow chart of the hardware part.

Figure 4(b) The flow chart of the software part.


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3.0 Results and Analysis

3.1 Display Waveforms and Receivers Output Voltages Values

Figure 5 The Front Panel of subpart programming 1.

Figure 6 The Block Diagram of the subpart programming 1.


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Analysis

This Front Panel as shown in Figure 5 was built to display the waveforms and the

values of the output voltages of the receivers. At this panel, its represents of three

receivers walkie-talkies named as Receiver 1, 2 and 3. Voltage Rx icon (x=1, 2 and 3) is

for I/O Traditional DAQ Channel for Tag Constant which function as a constant input for

a tag and/or a VI. By clicking the arrow at it, the name of analog input channel was

selected. There are three analog input channel names as Voltage, Voltage1 and Voltage2.

This analog input channel was configured earlier at Data Neighborhood in Measurement

& Automation. Numeric Rx is Numeric Indicator which functions to display the digital

values of the receivers and the Waveform Graph is to display the voltage waveform of

the receiver. For Block Diagram as shown in Figure 6, all icons were placed in the While

Loop that repeats the subdiagram inside it. AI Acquire Waveform, was used to

acquire a specified number of samples at a specified sample rate from a single input

channel and the output were links to both of Waveform Graph and Numeric Rx.


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3.2 Display Values of the Conversion of Output Voltages to Signal Strength




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Analysis

This part is for conversion of the voltage to signal strength in decibel (dBm). At

Front Panel, there are two values displayed which are for receivers voltage and

receivers signal strength as shown in Figure 7. For the Block Diagram, the conversion

formula is placed in Formula Node. Its use as to evaluate mathematical formula and

expressions similar to C on the block diagram. Semicolon (;) must be placed at the end of

formula because the Formula Node is case sensitive as shown in Figure 8. The input and

output must be declared in order to avoid error. The input is receivers voltage is a

Numeric Control while the output is the receiver signal strength is a Numeric Indicator.

The function of the Numeric Control is to manually insert the receivers output voltage

value and the Numeric Indicator is use to automatically calculate the Numeric Control

value using the formula and display the value at the Front Panel.


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3.3 Display the Location of the Object




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Analysis

The last subpart of the programming using LabVIEW is to display the location of

the object. At Front Panel as shown in Figure 9, the object is in red symbol at Display

graph. Numeric Control for x, y and z are the output voltages from the receivers

while Numeric Indicator for a and b are the output after the calculation using

Triangulation Formula. The locations of the Receiver 1, 2 and 3 also displayed at the

Front Panel. At Block Diagram as shown in Figure 10, the Triangulation Formula is

placed in the Formula Node that case sensitive. For example, * symbol is used for the

multiplication operation to avoid any error. The inputs of the loop are x, y and z

while the outputs are a and b. For plotting the location of the walkie-talkie, the both

outputs were Bundle together. The Bundle use to assemble a cluster from individual

elements. Build Array, function as concatenates multiple arrays or appends elements to

an n-array was used to append the output cluster from the Bundle. Then, the output from

Build Array was connected to XY Graph (Display) that used for plotting the objects

location.


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5.0 Conclusion and Future Recommendation

As conclusion, Objects Tracking Using Triangulation Method is a project that

can track location of an object inside the building. This project is a compliment of GPS

System in which GPS has limitation of the satellites coverage area that does not cover

inside the buildings. To get the precise location of the object, this project needs at least

three receivers and applies it to the triangulation formula. The greater number of the

receivers, the precise the coordinate or the location of the object.

First objective of this objective is to determine the appropriate triangulation

formula, [1], the objective is successfully achieved. The formula is:

Forx-position,

x =

Fory-position,

y =

Where:

a = output voltage receives from Receiver 1, R1.

b = output voltage receives from Receiver 2, R2.

c = output voltage receives from Receiver 3, R3.


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Second objective is to find the relation of signal strength sent from transmitter to

the receiver with distance also has been achieved successfully. The walkie-talkie output

is in voltage and has to be converted to decibel value to get the receiver signal strength,

[2]. For the conversion, the formula is:

dBm = 20 log10 ( )

Where:

V= the output voltage from the receiver in mV.

Table 3 The values of Receivers signal strength in dBm.

Distance(m)

Receivers SignalStrength(dBm)

0 34.8

1 33.24

2 31.76

3 30.42

4 28.58

5 25.8

6 22.22

7 18.2

8 10.2

9 -3.81

10 -11.77

Figure 11 Graph Signal Strength (dBm) versus Distance (m).

From the graph as shown in Figure 11, the signal strengths decreased with the

increase of the distances. The graph is not linear because of the factor of logarithm.


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Third objective is to build a model to establish triangulation method also has been

completed successfully. The model is consisting of a walkie-talkie for an object or

transmitter, and three walkie-talkies for the receiver as shown in Figure 3.

The last objective of this project is to display objects location using the

LabVIEW software also successful as shown in Figure 9.

For future need, this project can be modified to be a better project. First, the

usage of walkie-talkie can be replaced to a light or simple RF that has the same function

as walkie-talkie. The simple and light RF is easy to carry and portable.

This project can only track an object at any one time. For the future

recommendation, multiples objects can be tracked easily in a display on the monitor. The

operator can manage the situation easily and all the problems can be overcome in a short

time. This project is suitable to the dangerous and risky places such as in an oil and gas

plant.

Other than that, this project is manually input the output voltages of the receivers

by the user to get the values of signal strength and to display the objects location. For

future recommendation, this project can be better when the output voltages of the

receivers are automatically input to the programming. This can make this system running

smoothly and decreased the time needed.

Lastly, the display on the monitor that displays the location of the object can be

improved by integrating the display with the map of the area.


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Appendix

1. Object Tracking using Triangulation Method has several objectives:

a) Determine the appropriate triangulation formula.

b) To find the relation of signal strength sent from transmitter to the receiver

with distance.

c) Build a model to establish triangulation method.

d) To display objects location using the LabVIEW (Laboratory Virtual

Instrumentation Engineering Workbench) software.

2. Generally, the scopes of this project are:

a) Design a programming system to find location from the signal strength

among object (transmitter) to receiver to use in triangulation method

formula by using the LabVIEW software in C programming.

b) Build a hardware system that can detect an object in the confined area,

which consists of transmitter and receiver.


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References

1. Inderjit Singh (2007), Real-time Object Tracking with Wireless Sensor

Networks Lule University of Technology, Prague: Master Thesis.

2. http://www.sengpielaudio.com/calculator-volt.htm

14th February 2008, 8 pm.

3. Portable Radios Service Manual Radius P200, Motorala Inc.
http://www.sengpielaudio.com/calculator-volt.htmhttp://www.sengpielaudio.com/calculator-volt.htm

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