DIGITAL VOLTMETER USING 8051 MICROCONTROLLER
A PBL Report
On
MICROPROCESSORS AND MICROCONTROLLERS
LABORATORY
B.Tech, VII semester
(A3 Regulation)
Submitted by
B. SRINIVASA PARDHA CH. NARASIMHA
SARADHI NAIDU
(21331A0211) (21331A0220)
K. SRINU
(21331A0237)
Under the guidance of
Dr. SARAT KUMAR SAHU M.Tech., Ph.D
PROFESSOR
EEE
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
MVGR COLLEGE OF ENGINEERING (A)
Approved by AICTE, New Delhi Permanently Affiliated to JNTU - GV
Re-Accredited by NBA and NAAC, listed u/s 2(f) and 12(B) of the UGC Act
1956 Vizianagaram, Andhra Pradesh-535005.2023 – 2024
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Table of contents
S.NO Contents Page No
1. ABSTRACT 3
2. INTRODUCTION 4
3. THEORY 5
4. CIRCUIT DIAGRAM 6
5. SIMULATION 8
6. APPLICATIONS 9
7. RESULT ANALYSIS 10
8. CONCLUSION 10
9. REFERENCES 10
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ABSTRACT
Digital voltmeters play a crucial role in measuring voltage levels accurately
across various electronic circuits and systems. This project aims to design and implement a
Digital Voltmeter using the 8051 microcontroller, a widely used microcontroller in embedded
systems. The proposed voltmeter utilizes the microcontroller's analog-to-digital conversion
(ADC) capabilities to measure voltage inputs and displays the results digitally.
The project begins with interfacing the 8051 microcontroller with an analog
voltage sensor, typically a voltage divider circuit or a dedicated ADC module. The
microcontroller samples the analog voltage and converts it into a digital format using its
built-in ADC. The converted digital value is then processed to calculate the corresponding
voltage level based on calibration factors.
To provide a user-friendly interface, the digital voltmeter employs a liquid
crystal display (LCD) to present the measured voltage in a readable format. Additionally,
push buttons or a keypad may be integrated for user input, allowing features such as range
selection or calibration adjustments.
Simulation of the Digital Voltmeter is performed using a suitable simulation
tool such as Proteus or MPLAB X Simulator. The simulation process validates the
functionality of the voltmeter design, including ADC operation, voltage measurement
accuracy, and LCD display output. Through simulation, potential design flaws or errors can
be identified and rectified before hardware implementation, ensuring the reliability and
correctness of the final product.Overall, the Digital Voltmeter project offers a practical
demonstration of utilizing the 8051 microcontroller for voltage measurement applications,
providing a versatile and cost-effective solution for electronic enthusiasts, hobbyists, and
professionals alike.
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INTRODUCTION
In the realm of electronics, voltage measurement stands as a fundamental
aspect of circuit analysis, troubleshooting, and system monitoring. Digital Voltmeters
(DVMs) serve as indispensable tools for engineers and hobbyists alike, providing accurate
and reliable voltage readings across a wide range of applications. With the rapid advancement
of microcontroller technology, the integration of digital processing capabilities into voltmeter
designs has become increasingly prevalent, offering enhanced functionality and flexibility.
This project focuses on the design and implementation of a Digital
Voltmeter utilizing the 8051 microcontroller. The 8051, renowned for its versatility and ease
of use, serves as the cornerstone of countless embedded systems due to its robust architecture
and extensive peripheral support. By harnessing the capabilities of the 8051 microcontroller,
this project aims to develop a cost-effective and efficient solution for voltage measurement
tasks.
The proposed Digital Voltmeter system comprises both hardware and
software components, including an Analog-to-Digital Converter (ADC) for voltage signal
conversion, an LCD display for user-friendly output, and input protection circuitry to
safeguard the microcontroller from potential damage. Through careful integration and
programming, the 8051 microcontroller orchestrates the operation of these components,
ensuring accurate voltage measurement and display.
Furthermore, this project incorporates simulation as a crucial aspect of the
design process. Simulation offers a platform for testing and validating the functionality of the
Digital Voltmeter design in a virtual environment, allowing for iterative refinement and
optimization before hardware implementation. By leveraging simulation tools, potential
design flaws can be identified and addressed early in the development cycle, thereby
enhancing the reliability and performance of the final product.
In summary, the Digital Voltmeter using the 8051 microcontroller
represents a practical and versatile solution for voltage measurement applications. By
combining the computational power of the 8051 microcontroller with simulation-based
validation, this project aims to deliver a robust and efficient tool for voltage measurement
tasks, catering to the needs of electronics enthusiasts, students, and professionals alike.
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THEORY
1.Voltmeter:
Voltmeter is a measuring instrument, used to measure the voltage difference between
two points in electrical network. Generally there are two types of voltmeters – one is analog
voltmeter and the other one is digital voltmeter. In analog voltmeter a pointer moves on the
scale to represent the voltage. Digital voltmeter directly displays the voltage in digits with the
help of analog to digital converter.
2.Digital Voltmeter using 8051 Microcontroller :
This project measures the input voltage from 0V to 5V. Here, the input voltage should
be DC voltage to get the accurate output on LCD. If you apply AC voltage as input, then will
see the continuous running numbers on LCD as AC varies continuously.
The major components in this project are 8051 microcontroller and ADC0804. In this
project, we use analog to digital conversion process to display the voltage.
3.Analog to Digital Conversion:
In real world, mostly we find analog data. To manipulate this data using digital
systems, we need to convert analog data to digital, so that microprocessor or microcontroller
is able understand and manipulate the data.
1. Transducer: Transducer or sensor is used to convert the physical quantity to electrical
energy. Light dependent resistor, temperature sensor, humidity sensor, gas sensor etc.
are examples of transducers.
2. ADC (Analog to Digital Converter): ADC converts the input electrical voltage to
Digital value.
3. Digital System: this system reads input digital data and displays the physical quantity on
LCD for understanding purpose.
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Here ADC IC generates the output digital value based on the input electrical voltage. The
8051 microcontroller reads this digital value and displays it on LCD.
Digital Voltmeter using 8051 Microcontroller Circuit Diagram
Circuit Components:
1. AT89C51 micro controller
2. ADC0804 IC
3. AT89C51 programming board
4. Variable resistor
5. adaptor or DC battery
1.AT89C51 micro controller:
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer
with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device
is manufactured using Atmel’s high-density nonvolatile memory technology and is
compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip Flash
allows the program memory to be reprogrammed in-system or by a conventional nonvolatile
memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip,
the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-
effective solution to many embedded control applications.
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Fig 1.0
2.ADC0804 IC :
The ADC0804 is a CMOS 8-bit successive approximation A/D converters
that uses a differential potentiometric ladder – similar to the 256R products. These converters
are designed to allow operation with the NSC800 and INS8080A derivative control bus with
TRI-STATE? output latches directly driving the data bus. These A/Ds appear like memory
locations or I/O ports to the microprocessor and no interfacing logic is needed. Differential
analog voltage inputs allow increasing the common-mode rejection and offsetting the analog
zero input voltage value. In addition, the voltage reference input can be adjusted to allow
encoding any smaller analog voltage span to the full 8 bits of resolution.
Fig 1.2
3.AT89C51 programming board :
Fig 1.3
4.Variable resistor :
A resistor of which the ohmic resistance value can be adjusted. Either
mechanically (potentiometer, rheostat) or electronically (digital potentiometer).
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Fig 1.4
PROJECT STEPS :
1. Initially burn the program to the at89c51 microcontroller.
2. Now give the connections as per the circuit diagram.
3. Connect variable resistor at the input of probes to vary the input analog input voltage.
4. make sure that maximum analog input voltage should be less than 5V DC
5. Connect a digital multi meter at the Pot to measure the input voltage.
6. Now switch on the board supply.
7. Now observe both LCD and digital multi meter, both displays the same voltage.
8. Slowly increase the analog input voltage by varying the pot, now you can observe that
both multimeter and LCD displays the same voltages so that we can say that voltmeter
is working properly.
9. Switch of the board supply.
SIMULATION :
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OUTPUT :
APPLICATIONS
1. Electronics testing: Ensuring accurate voltage measurements for component analysis and
circuit debugging.
2. Battery monitoring: Providing real-time voltage readings to optimize battery performance
and prevent overcharging/discharging.
3. Industrial automation: Monitoring voltage levels in machinery and equipment for efficient
operation and preventive maintenance.
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4. Embedded systems development: Facilitating voltage measurement in microcontroller-
based applications such as sensor interfaces and motor control systems.
5. Education and training: Teaching principles of voltage measurement and microcontroller
interfacing in academic and vocational settings.
RESULT ANALYSIS
The Digital Voltmeter project employing the 8051 microcontroller has undergone thorough
result analysis, affirming its effectiveness and reliability in voltage measurement applications.
Through simulation testing, potential design flaws were identified and addressed, ensuring
the robustness of the final product. Upon hardware implementation, the Digital Voltmeter
demonstrated accurate and real-time voltage readings, proving its suitability for diverse
applications including electronics testing, battery monitoring, and industrial automation. The
project's success underscores the value of simulation-based validation and highlights the 8051
microcontroller's versatility in embedded systems development. Overall, the result analysis
confirms the Digital Voltmeter's efficacy in meeting voltage measurement needs across
various domains, contributing to advancements in electronic instrumentation and system
monitoring.
CONCLUSION
In conclusion, Digital Voltmeters based on the 8051 microcontroller offer versatile solutions
for voltage measurement across a multitude of applications. From electronics testing and
battery monitoring to industrial automation and education, these voltmeters play crucial roles
in ensuring system reliability, optimizing performance, and facilitating learning. By
providing accurate voltage readings and enabling real-time monitoring, they contribute to
enhanced efficiency, safety, and functionality in various electronic and electrical systems.
With their widespread applicability and ease of integration, Digital Voltmeters based on the
8051 microcontroller continue to be indispensable tools in diverse fields, driving innovation
and progress in the realm of electronics and embedded systems.
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REFERENCES
1. https://www.electronicshub.org/digital-voltmeter-using-8051-microcontroller/
2. https://www.youtube.com/watch?v=iJRmYLNbrkk
3. https://electronicsmaker.com/digital-voltmeter-using-8051-microcontroller
4. https://www.mathaelectronics.com/digital-voltmeter-using-8051-microcontroller/
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