1. N. Anju Latha, B. Rama Murthy, U. Sunitha / International Journal of Engineering Research
and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1440-1444
Design And Development Of A Microcontroller Based System For
The Measurement Of Blood Glucose
N. Anju Latha1*, B. Rama Murthy1, U. Sunitha2,
1. Department of Instrumentation, Sri Krishnadevaraya University, Anantapur, A.P., INDIA
2. Department of Electronics, Sri Krishnadevaraya University, Anantapur, A.P., INDIA
Abstract
Diabetes Mellitus is a group of metabolic diabetes, so lifelong treatment is the only alternative
diseases characterized by high blood sugar with continuous monitoring with diet control. Blood
(glucose) levels which results from defects in glucose of a person has also been routinely
insulin secretion. In the present study, a measured at medical checkups. There are different
microcontroller based system for the methods of in blood glucose measurement,
measurement of blood glucose is designed and Amperometric method, Spectroscopic method,
developed. It is based on the Amperometric Calorimetric method. In self measurement blood
method. A PIC 18F4520 microcontroller is used Glucose meters amperometric method is mainly
in the present study. LCD module is used to used [6]. Glucose measurement technique used
display measured values of blood glucose oxidation method. The whole operation is
glucose.The MAX232 is a dual line very simple with enzymes oxidation, which transfers
driver/receiver, converts signals from an RS- electrons to electrodes.
232 serial port to TTL compatible signals is There is evidence that the chorionic
interfaced with the microcontroller. Software is complications of diabetes are related to the duration
developed in C language using MPLAB IDE for and severity of hyperglycemia (diabetes control and
the Microchip Technology, due to the inherent complications Trial Research group 1993, UK
language flexibility, the extent of support and its prospective diabetes study group 1998). However
potential for portability across a wide range of good diabetic control is very difficult to achieve in
hardware. The instrument is tested and results many diabetic patients and frequent blood glucose
are found to be satisfactory. The instrument is testing is needed to detect hyper and
handheld, rugged, low cost, low energy hyperglycemia[7]. The most investigated technology
consumption, wearable and cost effective for in vivo glucose monitoring is based on
compared to the other commercially available. implanted Amperometric enzyme electrodes [2]
(Mastrototaro, 2000, sachedina and Pick up, 2003).
Keywords: Blood glucose measurement,
Amperometric method, PIC 18F4520 Tight control of blood glucose levels
microcontroller, RS232 level translator and achieved through frequent blood glucose monitoring
MPLAB embedded workbench IDE for microchip. has been shown to be effective in reducting
complicatins such as Retinopathy, Nephropathy and
I. INTRODUCTION Neuropathy [3,4]
The blood glucose is an important criterion
to discriminate the health condition of patients in Principle:
clinical field. Blood glucose of a patient is measured In the present paper, we measure the blood
3-4 times per a day in constant timer interval. glucose based on Amperometic method. The
Diabetes is a disease where the body doesn‟t glucose sensor [5] is an electrochemical diagnostic
properly use or produce insulin [1]. Insulin is a strip which used glucose oxidase enzymes. When
hormone produced in the human body which is need blood sample is applied, the enzyme becomes
for the conversion of sugar, starches and other food catalytically active and mediator compound transfer
into energy. Without insulin the body would not be electrons to the electrode. The electrical signal is
able to receive the amount of energy needed to then processed, amplified and converted into display
function, which is why diabetes is such a serious by microcontroller.
disease. There are two types of diabetes Type I and
Type II. Type I diabetes is where an individual‟s Glucose Oxidase
body doesn‟t produce insulin. Type II diabetes is Gluconic
where an individual body doesn‟t properly use Glucose + acid +
insulin combined with a relative insulin shortage O2 + H2O H2O2
within the body. Type II diabetes is the more GOD
common type with about 90% of people with
diabetes having this form. There is no cure for
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2. N. Anju Latha, B. Rama Murthy, U. Sunitha / International Journal of Engineering Research
and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1440-1444
II Experimental
A. Hardware Design
The block diagram of the microcontroller
based system for the measurement of blood glucose
is shown in fig 1. An Illustrative schematic diagram
is shown in fig2.
Liquid Crystal Display
Glucose Test Glucose detection Personal
Stripe circuit Computer
PIC 18F4520
Micro
Controller
Filter circuit MAX 232
A/D conversion
Fig1: Block Diagram of Design and Development of Microcontroller based system for the measurement of
Blood Glucose.
R1 R2
22K 1K
R3 -5V
LM358 VCC
R4
1 100K +5V X2
1 2 2K 1 8 1
2 3 2 1 8 7 U1
MAX232 6
11
32
4 3 3 2 7 6 7 2
5 4 4 3 6 5 2 25 10 T2OUT 7
VDD
VDD
5 -5V 4 5 3 RA0/AN0 RC4/TX 26 9 T2IN 8 3
4 RA0/AN1 RC4/RX R2OUT R2IN C7 8
5 RA0/AN2 R18 1 4
sensor 6 RA0/AN3 1K 2 1 1 9
7 RA0/TCLK 3 2 C+ 3 5
33 RA0/AN5 40 R19 100 4 3 11 C1- 4 C4 10uf
34 RB0/INT RB7/PGD 39 5 4 13 T1IN C2+ 5
35 RB1 RB6/PGC 38 6 5 14 R1IN C2- 2
36 RB2 RB5 19 7 6 12 T1OUT V+ 6 C6
37 RB3/PGM RD0/PSP0 20 8 7 R1OUT V- 10uf
RB4 RD1/PSP1 8 5V
R5 23 21 9
10K 18 RC4/SDI RD2/PSP2 22 10 9 C5
C1 17 RC0/SCK RD3/PSP3 27 11 10 10uf
R9 13 RC0/CCP1 RD4/PSP4 28 12 11 10uf
22K 14 OSC1/CLKIN RD5/PSP5 29 13 12
OSC1/CLKOUT RD6/PSP6 13
5MHz
30 14
R6 C4 C2 1 RD7/PSP7 15 14
1K C7 47nF ~MCLR/VPP 5V 16 15
1UF 24 16
15 RC4/SDO
RC0/TIOS0 8
R7 R10 16 RE0/RD 9
LCD
22K 2.2K RC0/TIOS1 RE1/WR 10
RE2/CS
TL072CP 31
VSS
-5V R8 C6 5V 12
33K 100nF 1 8 VSS
C8 2 1 8 7
3 2 7 6
4 3 6 5
PIC18F4520
4 5
47nF
C3
100nF C5
100nF
+5V
R13 10K
LM358 R11
10K
R12 1 8 R14
2 1 8 7
3 2 7 6
100 4 3 6 5 220
4 5
7486 +5V
14
1 14 13
R15 1K 2 1 13 12
3 2 12 11
4 3 11 10
5 4 10 9
6 5 9 8
+5V R16 1K 7 6 8
7
R17 1K
Figure 2: Schematic diagram of Design and Development of Microcontroller based system for the measurement
of Blood Glucose.
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3. N. Anju Latha, B. Rama Murthy, U. Sunitha / International Journal of Engineering Research
and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1440-1444
Sensor unit with Biosensor Biosensor is connected to amplifier LM358 and
According to the American diabetes ADC.
Association (ADA) [8], the term diabetes mellitus
describes a metabolic disorder of multiple aetiology Signal conditioning unit
characterized by chronic hyper glycaemia with In general any Instrumentation system
disturbances of carbohydrate, fat and protein consists of various units staring from sensors to data
metabolism resulting from defects in insulin representation units, among that signal conditioning
secretion, insulin action, or both. The effects of is a vital process. The glucose measurement
diabetes mellitus include long– term damage, originates as a small current generated by the
disfunction and failure of various organs. Diabetes chemical reaction occurring in the test strip. The test
mellitus may present with characteristic symptoms strip contains glucose oxidase, a chemical that binds
such as thirst, polyuria, blurring of vision, and to D-glucose to start a redox reaction. The redox
weight loss. reaction breaks down the glucose and releases
A biosensor is a sensor that makes use of electrons. The flow of electrons is known as current
biological or living material for its sensing function. and is collected by electrodes built-in to the test
There are three main parts of a biosensor: (i) strip. The current is converted to voltage through the
biological detection elements, which recognize the use of a current-to-voltage converter.
substance of interest, (ii) a transducer, which When test stripe is inserted PIC micro
converts the biorecognition event into a measurable controller sense the presence of the strip. The
signal and (iii) a signal processing system, which current output from the glucose test strip is
converts the signal into a workable form. connected to inverting input of the LM358 [9]. The
The basic operation of glucose biosensor is LM358 dual operational amplifier, low power drain,
based on the fact that the enzyme glucose oxidase a common mode input voltage range extending to
(GOD) catalyses the oxidation of glucose to ground/VEE, eliminating the necessity for external
gluconic acid. The enzyme acts as a biorecognition biasing components. The current is converted to a
element, which recognizes glucose molecules. These voltage in LM358.A current-to-voltage converter is
enzyme molecules are located on an electrode simply an op amp with a feedback resistor. The op
surface, which acts as a transducer. As soon as the amp is used as a high impedance source that forces
enzyme recognizes the glucose molecules, it acts as all of the current to flow through the resistor. The
a catalyst to produce gluconic acid and hydrogen average current I produced by the glucose test strip
peroxide from glucose and oxygen from the air. The is 20μA. V is chosen to be 2 volts, then R = 100000
electrode recognizes the number of electron transfer Ohms
due to hydrogen peroxide/oxygen coupling. This The output of LM 358 is given to the filter
electron flow is proportional to the number of circuit. The filter circuit uses a TL072 [10] Low
glucose molecules present in blood. The glucose Noise JFET Input Operational Amplifier and is
sensor is an electrochemical diagnostic strip which configured as a 100 Hz Sallen-Key Low Pass
uses glucose oxidase enzymes in conjunction with Butterworth filter. The glucose measurement is
three electrically conductive electrodes. Two of taken from a single acquisition from the analog-to-
these electrodes are „working‟ electrodes meaning digital converter. When a sample is applied to the
they are the measured electrodes, and the third is a test strip the voltage jumps to a peak value and then
reference electrode as shown in fig 3. begins to decay linearly between 1 and 5 seconds.
The voltage reading is taken after 2 seconds the
sample is applied. Fig 4 shows a typical voltage
curve for glucose.
Fig 4: Glucose voltage curve.
The voltage level is then converted to a
glucose concentration using equation
Concentration = (voltage)
x922.23− 22.9
Fig 3: Schematic layout of a biosensor and test The Micro controller PIC 18F4520 is used
stripe to connect each component of the meter. The
The signals from glucose sensor are transmitted to processor is responsible for the analog-to-digital
next stage of signal condition unit. The output of the conversion, LCD control, user interface, and
communication with a serial device. The
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4. N. Anju Latha, B. Rama Murthy, U. Sunitha / International Journal of Engineering Research
and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1440-1444
microcontroller uses a 5 MHz clock. The analog-to-
digital converter is configured with two control
registers, ADCON0 and ADCON1. ADCON0 is
used to configure the conversion clock, the input
channel. The analog-to-digital converter is set up to
use an Fosc/8 conversion clock, read channel 0, and
turn the module on. The maximum device frequency
is 5 MHz.
Microcontroller
In the present study, we have used
PIC18F4520 [11] microcontroller for the
measurement of blood glucose. PIC18F4520 is an
Enhanced Flash Microcontroller with Power
Managed Modes. The PIC microcontrollers have
high computational performance with the addition
of high endurance, Enhanced Flash program
memory. The PIC18F4520 introduces design
enhancements that make these microcontrollers a
logical choice for much high performance, power
sensitive applications. it consists of Three
programmable external interrupts, Four input
change interrupts, Enhanced
Capture/Compare/PWM (ECCP) module, Master
Synchronous Serial Port (MSSP) module supporting
3-wire SPI and I2C Master and Slave Modes,
Enhanced Addressable USART module, 10-bit, 13-
channel Analog-to-Digital Converter module, Dual
analog comparators with input multiplexing, High-
current sink/source 25 mA/25 mA
RS-232 (Recommended Standard 232) is a standard
for serial binary data signals connecting between a
DTE (Data Terminal Equipment) and a DCE (Data
Circuit-terminating Equipment). It is commonly Figure 5: Flowchart for design and development of
used in computer serial ports. Here, we use MAX microcontroller based system for the measurement
232 (RS-232) for serial communication in between of blood glucose.
microcontroller and personal computer [12]. The PC is the standard computing device
for the „C‟ compiler. [14]. to development of C
programs for an PIC18F4520 executing on a PC is
Display unit
now familiar with MPlab IDE for Microchip [15].
The measured Blood Glucose data are
The flowchart of the program is presented in Figure
displayed on the Liquid Crystal display. In present
work we are using LM16200 [13] (16 x 2 character) 5. A software method of digitally sampling the
LCD display. The LCD connects to the concentration of glucose levels is described. The
micro controller program controls the external
microcontroller using 14 pins. There are eight
devices and measures the input signals from the
parallel pins used for data transfer, three pins for
sensor and displays the output. Figures 5 contain the
enable, instruction/register select and read/write
flow chart for the present designed instrument used
control. The data and instructions are sent through
to determine the blood glucose. When we insert a
D0-D7 lines of LCD screen.
glucose test stripe in the meter, the microcontroller
Lcd displays requires less power and it is
used display any alpha-numeric and symbols. The automatically detect the presence of stripe, when we
display has a built in controller with synchronous drop blood sample, it measure the glucose
concentration and display the output blood glucose.
serial and parallel interfaces. The display has a
lifetime of about 10,000hours.
III. RESULTS AND OBSERVATION
B. Software The performance of the microcontroller
„C‟ programme language is used for the based system for the measurement of blood glucose
development of Blood glucose meter. The „C‟ is designed, developed and tested. Blood glucose
programming language is growing in importance values are illustrated on the two lines of the display
and has become the standard high level language for and transfer values to personal computer. Constant
real-time embedded applications. attention has been made on applying blood sample 1
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5. N. Anju Latha, B. Rama Murthy, U. Sunitha / International Journal of Engineering Research
and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1440-1444
micro liter of blood is the required for testing. The Ilse Milants, R.N., Mona Eerdekens, R.N.,
blood sample is applied correctly in a reaction zone; Pieter J. Wouters, Bart De Moor, and Greet
the enzyme becomes active and mediator compound Van den Berghe, Journal of Diabetes
transfer electrons to the electrode. Low power Science and Technology Volume 2, Issue
consumption, long shelf life, and environmental 6, November 2008
operating characteristics (least affected by 2. “Fluoresence based glucose sensor”, John
temperature, humidity, and pressure), were very .C.Pick up, Faeiza Hussain,Nicholas D
important considerations in component and design Evan, olaf J. Rolinski,David J.S. Birch, Bio
selection. The blood glucose measurements were sensors & Bio electronics, 20 (2005),Pg
tested and the results are shown in Table 1. 2555-2565.
S. Actual Blood ACCU CHEK Present designed 3. The UKDS study group: Intensive blood
No Glucose values blood glucose Blood glucose glucose control with sulphonylueas or
mg/dl meter mg/dl meter mg/dl Insulin compared with conventional
1 93 93 92 treatment and risk of complications in
2 136 134 135 patients with type 2 diabetes (UKPDS33),
3 213 211 212 Lancet 1998;352:837-853
4 183 182 182 4. The diabetes control and complications
5 149 148 149 trial (DCCT): The effect of intensive
Table 1: Blood Glucose values treatment of diabetes on the development
and progression of long term complications
The results of the present study are in good in insulin dependent diabetes Mellitus: the
agreement with the standard blood glucose meters New England Journal of Medicine 1993;
(ACCU CHEK & One Touch Ultra instruments). In 3299140:977-986
the present study, a microcontroller based system, 5. “Electrochemical biosensors – principles
which converts the glucose concentration in the and applications”, Miroslav Pohanka1, Petr
blood sample into voltages compatible with Skládal2, Journal of APPLIED
microcontroller input requirements. The BIOMEDICINE ,57–64, 2008,ISSN 1214-
microcontroller software determines the validity of 0287
the voltage and analyze. Once the test stripe has 6. Worthington, D. (1990). "Use of models in
inserted in the meter, the glucose concentration the self-management of insulin-dependent
corresponding to the applied blood sample is diabetes mellitus," Computer Methods and
displayed as blood glucose. We got good accuracy Programs in Biomedicine, vol. 32(3-4), pp.
when compared to YSI 2300 glucose analyzer [11]. 233-239.
7. Gabir MM, Hanson RL, Dabelea D,
IV. SUMMARY Imperatore G, Roumain J, Bennett PH,
The hardware and software features of a Knowler WC. Plasma glucose and
microcontroller based system for the measurement rediction of microvascular disease and
of blood glucose are described. The necessary mortality: evaluation of 1997 American
software is developed in C, using MPlab IDE for Diabetes Association and 1999 World
Microchip. The system is quite successful for the Health Organization criteria for diagnosis
measurement of blood glucose with an accuracy of of diabetes. Diabetes Care. 2000 Aug;
less than ± 2%. Our instrument protects data in the 23(8):1113-1118
event of power loss and does not require periodic 8. Definition, Diagnosis and Classification of
refreshing. This feature would enable the health care Diabetes Mellitus and its Complications,
team to use the recorded data to perform diabetes Part 1: Diagnosis and Classification of
mellitus variability studies. In the present paper, we Diabetes Mellitus World Health
used test strips designed for the One Touch Ultra Organization Department of
glucose meter made by Life scan, PIC Noncommunicable Disease Surveillance
microcontroller, RS232 for transferring data to Geneva WHO/NCD/NCS/99.2
personal computer for further processing and LCD 9. LM358 datasheet, www.national.com
to display which operated with Less power and 10. TL072 datasheet, www.ti.com
more bright. These are the novel parts when 11. PIC micro controller 18f4520 datasheet ,
compared to others. http://www.microchip.com(2008)
12. IC MAX 232 datasheet, www.maxim-
Reference ic.com (2006).
1. “Blood Glucose Measurements in Arterial 13. Lcd datasheet www.lampex.com
Blood of Intensive Care Unit Patients 14. RC-51 ANSI-C Compiler for the 8051
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