A MINI PROJECT REPORT
ON
Battery level indicator using lm3914 using proteus software
SUBMITTED
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF
BACHELOR OF TECHNOLOGY
IN
ELECTRICAL AND ELECTRONICS ENGINEERING
By
B. Manoj Kumar
(18761A0257)
UNDER THE GUIDANCE OF
Mr. A.V. Ravi Kumar
(Assistant Professor)
DEPARTMENT OF ELECTRONICS&INSTRUMENTATION ENGINEERING
LAKIREDDY BALI REDDY COLLEGE OF ENGINEERING (AUTONOMOUS)
Approved by AICTE, New Delhi, Affiliated to JNTU, Kakinada,
Accredited by NAAC & NBA , Certified by ISO 9001-2015
L.B. Reddy Nagar, Mylavaram-521230,
Andhra Pradesh
October 2021
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CERTIFICATE
This is to certify that the Mini Project report entitled Battery level indicator
using lm3914 using proteus software that is being submitted by B. Manoj
Kumar bearing Regd. No.18761A0257 in partial fulfillment for the award of the
Degree of Bachelor of Technology in Electrical and Electronics Engineering is a
record of the project work carried out by her under my guidance and
supervision.
Signature of Guide Head of Department
Mr. A.V. Ravi Kumar Dr. J. Siva Vara Prasad
( Assistant Professor) (Professor)
ACKNOWLEDGEMENTS
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The Satisfaction that accompanies the successful completion of any task
would be incomplete without the mention of people whose ceaseless co-
operation made it possible, whose constant guidance and encouragement
crown all efforts with success.
First and foremost, I would like to thank management for providing
excellent infrastructure and learning environment to carry out my mini
project work in the campus.
I humbly express my thanks to our Principal Dr. K. Appa Rao for
extending his support and for providing us with an environment to
complete mini project successfully.
I deeply indebted to our Head of the Department, Dr. J. Sivavara Prasad
who modeled us both technically and morally for achieving greater
success in life.
I extremely thankful to my guide Mr. A.V. Ravi Kumar, Department of
Electrical and Electronics Engineering, for her excellent guidance, timely
and valuable suggestions and encouragement that enabled the
completion of the mini project.
I also equally thankful to Mini Project Co-ordinators for their
motivational guidance and timely support that helps a lot in completion
of mini project in stipulated period.
I would like to thank all the teaching and non-teaching staff members of
Electrical and Electronics Engineering, who have extended their full co-
operation during the course of my mini project.
I would like to express my heartfelt thanks to my parents for their
unflinching support and constant encouragement throughout the period
of my mini project work for making it a successful one.
I thank all my friends who helped me sharing knowledge and by
providing material to complete the mini project in time.
B. Manoj Kumar
(18761A0257)
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INDEX
CONTENTS PAGE
NO:
ABSTRACT
05
INTRODUCTION
06
LM3914
07
Lm3914 pin configuration
07
Specifications 08
Proteus Design Suite 09
Circuit diagram
10
Circuit components
10
How to operate Battery level indicator circuit
11
Advantages 12
Applications
12
Limitations
12
Conclusion
13
References
14
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ABSTRACT
Technology on batteries has advanced over the years as a result of the need
to power portable devices that have risen in numbers in the last decade.
Just like primary cells, rechargeable batteries work in the same way, only
their chemical reactions are reversible. This project aimed at building a
system that would indicate the capacity level of a Nickel Metal Hydride
battery upon charging and discharging. The Nickel Metal Hydride battery
was selected in this project due to its preference among consumers.
However, since the principle behind the rechargeable battery technology is
similar, the system can be used to test other types of batteries. System
implementation involved designing and building a battery charger circuit
and a discharge circuit. Software design then followed, after which testing
was performed. The project uses a LM3914 driver IC use to drive 10 leds by
passing through it sufficient amount of current. Brightness of leds are
controlled by reference adjustable pin and reference out pin. The project
goal was achieved and results were presented through numeric figures,
charts and indicators. The system is expected to help in planning with
batteries to avoid halt of devices during operation. The results gathered
during testing point to possible reduced battery wastage. A better way to
handle batteries to conserve capacity has also been highlighted.
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INTRODUCTION
Battery level indicator is a circuit that is used to check the battery life. We
can easily recognize the battery level with the help of LED’s. It uses a
LM3914 driver IC use to drive 10 leds by passing through it sufficient
amount of current. Brightness of leds are controlled by reference adjustable
pin and reference out pin. A variable resistor is also deployed in the circuit
to have variable input voltage at pin 5 of the driver IC. Since the driver IC
has two modes of operation which is bar graph mode and dot mode, it
enables us to have indication of the battery life either in bar form or in dot
form. We can have colored leds to indicate state of the batteries like first
three leds will indicate low battery. Green leds will indicate full battery.
Thus by using various colored leds representation of battery life will be
made easy to understand. Cascading the driver ICs we can increase the
range of battery input in terms of voltage. In the below given block diagram
we have 4 blocks. One is the power supply. other is the driver IC itself. We
will have a led block and an input block. A reference input for comparison
purpose. Leds will glow according to the input given and the reference Input
present.
Power supply is ranging around 12 to
18V. Reference voltage is pre decided which is 1.25mV. Any dc signal lying
in the range of the power supply is judged and the level is indicated by the
leds. The current through the leds is controlled by the internal adjustment.
The battery level indicator consists of very less component and thus
occupies very little space of the surrounding. Since only DC input voltage
levels are indicated, components which work in AC supply can be used to
detect AC levels. Since AC voltage having continuously varying amplitudes
the leds will turn ON and OFF continuously making a good looking pattern.
Thus our battery level indicator can be used for decoration purpose also.
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LM3914
INTRODUCTION
LM3914 is an analog controlled LED driver IC, launched by the national
semiconductor in 1980. It can control 10 LED lights based on an analog
input voltage. It is best to alternate microcontroller ic where 10 LEDs have
to control so it reduces the hardware.
FEATURES
Internal voltage reference from 1.2 to 12v DC.
Programmable output current 2mA to 30mA.
LED driver outputs are current regulated.
No multiplexing interaction between outputs.
It supports wide range of temperature from 0 to 70 degree Celsius.
For bar graph display – connect 9th pin of IC to the supply
For dot display – leave the 9th pin of IC
LM3914 IC Pin Configuration
Pin1: (LED1, LED2, LED3,..LED10): These pins are allied to
LEDs.
Pin2: (Ground or V-): GND pin of the LM3914 IC
Pin3: (Vcc or V+): DC voltage from 3V to 18V as supply
Pin4: (RLO): Low-level voltage used for potential divider
Pin5: (Signal): Analog signal input based on which the LED is
controlled.
Pin6: (RHI): High-level voltage for potential divider
Pin7: (Ref Out): Reference voltage of Output
Pin8: (Ref Adj): Adjust pin
Pin9: (Mode): Choose among Bar or Dot mode
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Specifications
Its is Analog Controlled LED Driver IC
Controllable for LEDs: 10
3V to 18V Operating Voltage:
Analog Input voltage range: 1.2V to 12V
LED sink current: 2mA to 30mA
Both Bar/Dot mode available
More IC can be used to control up to 100 LEDs
Available in 18-pin DIP
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Proteus Design Suite
The first version of what is now the Proteus Design Suite was called PC-B
and was written by the company chairman, John Jameson, for DOS in
1988. Schematic Capture support followed in 1990, with a port to the
Windows environment shortly thereafter. Mixed mode SPICE Simulation was
first integrated into Proteus in 1996 and microcontroller simulation then
arrived in Proteus in 1998. Shape based autorouting was added in 2002 and
2006 saw another major product update with 3D Board Visualisation. More
recently, a dedicated IDE for simulation was added in 2011 and MCAD
import/export was included in 2015. Support for high speed design was
added in 2017. [1]Feature led product releases are typically biannual, while
maintenance based service packs are released as it is required.
The PCB Layout module is automatically given connectivity information in
the form of a netlist from the schematic capture module. It applies this
information, together with the user specified design rules and various design
automation tools, to assist with error free board design. PCB's of up to 16
copper layers can be produced with design size limited by product
configuration.
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CIRCUIT DIAGRAM
Circuit Components
LM3914 IC
LED’s -10 (Red – 3, Yellow – 4, Green – 3)
SPST Switch
Resistors – 18KΩ, 4.7KΩ, 56KΩ
Potentiometer – 10KΩ
12V Battery (to test)
Connecting wires
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How to Operate Battery Level Indicator Circuit?
Connect battery to be tested to the input of the circuit.
Now adjust the pot RV1 so that LED D1 just starts glowing.
Now increase the input Dc voltage slowly and observe the LED’s
First led will glow for 1.2V and second LED is for 2.4 V and so on.
With a little modification we can use this circuit to measure other voltage
ranges also. For this remove the resistor R2 and connect upper voltage level
to the input. Now vary the resistance of Pot RV1 till the D10 LED glows. Now
remove upper voltage level at the input and connect lower voltage level.
Connect a high value variable resistor in the place of resistor R2 and vary it
till the D1 LED glows. Now disconnect the pot, measure the resistance
across it and connect resistor of same value in place of R2. Now the circuit
is ready to monitor other voltage ranges.
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ADVANTAGES:
This IC can drive LED’s, LCD or vacuum fluorescent display.
You can cascade more IC’s up to 100 steps.
This IC can also work on 3V power supply.
In this we do not require resistor with the LED’s because current drive
to LED’s is regulated and programmed.
It will support wide temperature range from 0 degree to +70 degree
Celsius
APPLICATIONS:
We can use this circuit to measure car battery level.
This circuit is used to calibrate inverter status.
Limitations of the Circuit
This battery level indicator works only for small voltages.
This circuit is theoretical and may require some changes to work in
practical.
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CONCLUSION:
Battery level indicator will let you know the status of battery of a
device just by glowing the number of LED's.
For example four LED's are glowing means battery capacity is 40
percent.
LM3914 is a monolithic integrated circuit which senses the analog
voltage and derives 10 LED's providing a linear analog display.
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REFERENCES:
1. https://ieeexplore.ieee.org/document/7916544
2. https://youtu.be/OhwQmaCmDnM
3. https://tazabollywoodnews.000/VLCO6v
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