Hand in hand instrument replaces the old traditional way of measuring and testing in colleges and helps in easy way of understanding theoretical concepts based on practical knowledge. As there occurs shortage of instruments, long duration of calculation, large occupation of space, low accuracy, inconvenience come about in completing the work. A single Smart device which is a multipurpose handheld instrument overcomes the above difficulties and helps in measuring voltage, current, resistance, frequency, temperature, speed, sound and to observe waveforms for engineering students in the laboratories. In a single ARM Cortex M3 microcontroller all measurements are done and displayed within a fraction of time in the TFT graphical LCD display. The data and waveforms from oscilloscope can be saved and retrieved for future analyzing purpose which is done using a Micro SD memory card. The device is fully operated with touch screen and touch buttons. The device works with help of LPC1313, a powerful 32-bit ARM Cortex-M3 microcontroller from NXP Semiconductors.

1. INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY
VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303
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A Smart Handheld Measuring and Testing
Electronic Device with Touch Screen
K.KrishnaPriya, M.Nivetha, Ms.J.Rajeswari,M.E,
M.Precilla Priyadharsini, Assistant Professor,
B.E, Electrical and Electronics Engineering, Electrical and Electronics Engineering,
Velammal College of Engineering and Technology, Velammal College of Engineering and Technology,
Madurai, Tamil Nadu Madurai, Tamil Nadu
Mail.ID: kkpriya10@gmail.com Mail ID: j.rajeswari@vcet.ac.in
Abstract-Hand in hand instrument replaces the old traditional way of measuring and testing in colleges and helps in
easy way of understanding theoretical concepts based on practical knowledge. As there occurs shortage of
instruments, long duration of calculation, large occupation of space, low accuracy, inconvenience come about in
completing the work. A single Smart device which is a multipurpose handheld instrument overcomes the above
difficulties and helps in measuring voltage, current, resistance, frequency, temperature, speed, sound and to observe
waveforms for engineering students in the laboratories. In a single ARM Cortex M3 microcontroller all
measurements are done and displayed within a fraction of time in the TFT graphical LCD display. The data and
waveforms from oscilloscope can be saved and retrieved for future analyzing purpose which is done using a Micro
SD memory card. The device is fully operated with touch screen and touch buttons. The device works with help of
LPC1313, a powerful 32-bit ARM Cortex-M3 microcontroller from NXP Semiconductors.
Index Terms: LPC1313, ARM Cortex M3 microcontroller, NXP Semiconductor, Smart device.
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1 INTRODUCTION
An efficient multipurpose instrument is introduced to
measure and test electrical parameters and the output
waveforms of power electronics laboratoryexperiments
for easy access, accurate and reliable purpose.The
project deals with a smart portable handheld device. The
USB-UART device is used to have USB connectivity
for viewing of results and other measured values.
1.1Proposed System
The following are the features to be done:
Voltmeter
Ammeter
Ohmmeter
Tachometer
Audiometer
Logic Analyzer
3-axis motion monitor
Light Meter
Temperature Probe
Calculator
Hence, by interfacing all the above devices testing and
measuring of required electrical parameters can be done
in a single instrument using touch screen and touch
buttons.
2 SYSTEMDESCRIPTIONS
The system consists of several sensors, touch screen,
LCD TFT display and USB-UART which are interfaced
into a single ARM Cortex M3 microcontroller. The
block diagram of this multipurpose handheld device
with touch screen is shown in fig, 1.1.
2.1 ARM Cortex M-3
The Cortex-M3 processor, based on the ARMv7-M
architecture, has a hierarchical structure. It integrates
the central processor core, called the CM3Core, with
advanced system peripherals to enable integrated
capabilities like interrupt control, memory protection
and system debug and trace. These peripherals are

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highly configurable to allow the Cortex M3 processor
to address a wide range of applications and be more
closely aligned with the system requirements. The
Cortex-M3 core and the integrated components (Fig,
1.1) have been specifically designed to meet the
requirements of minimal memory implementation,
reduced pin count and low power consumption. The
main purpose of use of ARM Cortex is an efficient
memory usage for lower cost, low cost debugger and
trace, low latency interrupt handling scheme,
delivering in a field, reliable and secure automotive
and industrial control application, fine grain memory
protection, lower power consumption and faster access
to market.
Fig, 1.1 Block diagram of smart handheld measuring
and testing electronic device with touch screen
2.2 LPC1313
ARM Cortex M3 processor running at 72 MHz
frequency, 32Kb on chip program memory, 8kb
SRAM, Selectable boot up USB or UART and IIC
bus interface supporting full bus specification and
data rate with multiple address access and monitor
mode. Use of Integrated Power management unit
helps in minimumpower consumption during sleep,
deep sleepand deep power down mode. The
purpose of thewatchdog timer is to reset the
microcontroller within a reasonable amount of time
when it enters the erroneous state. Hence the debug
operation is perfectly done.
Fig, 1.2 LPC1313
2.3 Temperature Sensor
LM 35 series is an integrated circuit temperature
sensor whose output voltage is linearly proportional
to input temperature centigrade. It is more
advantageous than its predecessor as it generates
higher output voltage without any external
calibration It requires very low input current (60
Microampere) and maintains an accuracy of +/-
0.4ºC at room temperature and +/-0.8ºC over a
range of 0ºC to +100ºC. The main function of LM
35 is to convert the input temperature into an
analog electrical output which is given to the ADC
of microcontroller to convert it into digital data.
The digital value of temperature is then displayed
in the LCD display. It is rated for a range of -55ºC
to 150ºC.
2.4 Light-Dependent Resistor
A light dependent resistor also known as LDE,
photoresist, photoconductor or photocell is a
resistor whose resistance value always increases or
decreases depending on intensity of light. LDR
works both in light/dark circuits. It mainly works
on semi-conductive materials that are having high
resistance value. Materials have high resistance due
to the arrangement of electrons in crystal lattices.
Hence it is widely used in photographic light,
Alarm and event in street lights.
2.4 MEMS Accelerometer
LIS302DL is an ultra-compact, low power 3 axes
accelerometer. It includes IC interface and sensing
element. With the use of accelerometer, motion of

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objects can be detected and the data loss due to free
fall of the device can be restored again. Both
rotation and change of screen can be done using
accelerometer. Hence it is widely used in
touchscreen based devices such as mobile phones,
laptops and game controllers.
2.5 Current and Voltage Sensor
Conventionally current and voltage is measured
using ammeter and voltmeter respectively andthen
it leads to the development of Multimeter. Sensors
are now used to detect electrical signals into analog
or digital signals. These current and voltage signals
areinterfaced with ARM cortex M3 microcontroller
through I2C to measure voltage and current.
2.6 Buzzer
Buzzers are generally used to produce alarm when
there occurs over flow of supply or varying fault in
circuit. Once alarm gets produced we are capable of
finding fault position and then detecting them. They
are highly reliable in both electromagnetic as well
as piezoelectric model that is applicable to all
automotive applications. Early devices were based
on an electromechanical system identical to
an electric bell without the metal gong. Similarly,
a relay may be connected to initiate its own
actuatingcurrent, causing the contacts to buzz.
Often these units were anchored to a wall or ceiling
to use it as a sounding board. The word "buzzer"
comes from the rasping noise that
electromechanical buzzers make. A piezoelectric
element may be driven by an oscillating electronic
circuitry or another audio signal source, driven with
a piezoelectric audio amplifier. Sounds commonly
used to indicate that a button has been pressed are a
click, a ring or a beep.
2.7 Rotary Encoder
Rotary encoder is otherwise known as shaft
encoder, is an electromechanical device that
converts motion or rotation of shaft into analog or
digital signals. There are two types of rotary
encoder they are absolute and incremental.
Absolute is mainly used to specify the current
position of the shaft, whereas incremental encoder
is mainly to measure motion of shaft.Hence it is
widely used in applications like monitoring the
speed, position and number of rotations. Rotational
speed of motors is measured using Tachometer but
with the help of a rotary encoder, a portable device
helps in measuring speed.
Fig, 1.3 Rotary Encoder
3 SOFTWARE
Coding for interfacing the components with the
microcontroller is made in Embedded C language.
It is then converted into Hex code using
LPCXpresso IDE software and the coding is
burntinto the microcontroller using Flash Magic
software.
3.1 LPCXpresso IDE Software
It is a complete software chain tool which uses
Embedded C language for implementing NXP
microcontroller. LPCXpresso is an enhanced,
Eclipse based IDE development tool. It includes
GNC compiler, GDB debugger, linker and libraries.
LPCXpresso is implemented in two ways as Inbox
tool and starter kit. It performs all syntax coloring,
source formatting, function folding on and offline
actions.
Fig, 1.4 LPCXpresso IDE Library

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3.2Flash Magic Software
This software tool is used to burn the hex code
generated using LPCXpresso into the EEPROM of
ARM Cortex M3 microcontroller.
Fig, 1.5Flash Magic Software
4 RESULTS
The device has the following features built in:
Digital Signal Oscilloscope – used to monitor the
signals acquired through the inbuilt 10- bit A to D
converter. This device is a single channel, 100 KHz
bandwidth. The signals will be shown in color
waveforms 2GB Micro SD memory card.
Waveform Storage and Playback- used to generate
pulses at variable frequencies with added pulse
width control. Logic Analyzer is used to analyze
serial protocols such as UART. Voltmeter is used
to measure the input DC voltage. Ammeter is used
to measure the input DC current using current shunt
resistor drop. Ohmmeter is used to find the resistor
values, short circuits and components such as
diodes. Tachometer is used to measure the speed of
the rotating shaft of the motor using the Rotary
Encoder. Audiometer is used to monitor the audible
frequency signals sensed via Microphone circuitry.
3-axis Motion Monitor is used to measure
acceleration or tilt or motion on all three axis using
3-Axis MEMS Accelerometer. Light Meter is used
to measure the brightness of the incident light in
terms of Luminosity using Light Sensor.
Temperature Probe is used to measure the
atmospheric temperature or the temperatureof
anobject in degree Celsius. Calculator is used to
perform math calculations using touch screen
keypad.
Fig, 1.6Multipurpose handheld smart device
5 CONCLUSION
Electrical laboratory measuring devices and the
waveform storage device such as DSO are
combined in versatile equipment called smart scope
which facilitates the engineering students to use the
device even at lecture halls to study and analyze the
results of EDC, DLC and LIC laboratory
experiments. Use of a large number of equipment is
reduced, size is reduced, low power consumption,
more accuracy, helps students to use at any place
and cost is highly reduced compared to DSO and
multimeter.
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