INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303
A Smart Handheld Measuring and Testing Electronic Device with Touch Screen K.KrishnaPriya, M.Nivetha, M.Precilla Priyadharsini,
Ms.J.Rajeswari,M.E, Assistant Professor, Electrical and Electronics Engineering, Velammal College of Engineering and Technology, Madurai, Tamil Nadu Mail ID: j.rajeswari@vcet.ac.in
B.E, Electrical and Electronics Engineering, Velammal College of Engineering and Technology, Madurai, Tamil Nadu Mail.ID: kkpriya10@gmail.com
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.
———————————————————— 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.
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
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
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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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303 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, 1.2 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
Fig, 1.1 Block diagram of smart handheld measuring and testing electronic device with touch screen
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.
2.2 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.
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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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303 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.
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.
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.
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.
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 Fig, 1.4 LPCXpresso IDE Library
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.
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INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY VOLUME 5 ISSUE 2 – MAY 2015 - ISSN: 2349 - 9303 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.
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, 1.6Multipurpose handheld smart device Fig, 1.5Flash Magic Software
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4 RESULTS
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.
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
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