DIGITAL OBJECT COUNTER

Digital object counter is a device which is designed to count the object which is passing from above it or by touching it or whatever depending upon the method of getting signal from the transducer. But main work of digital object counter is the counting of things or objects. It can be done by using LDR or THERMISTOR .

Its one of the 8051 based microcontroller from ATMEL.

Using a microcontroller greatly reduces the component count while providing more features that could be found using dedicated logic IC’S

By using this IC cost is also lowered.

INTRODUCTION TO AT89C2051

89C2051 FEATURES• It’s a low voltage, high performance CMOS

8-bit micro-computer.• its compatible with the MCS51.• 2K bytes of Flash programmable and

erasable read only memory.• 2.7 – 6V operating range.• 15 I/O lines.• two 16-bit timer/counters.• 6 interrupt sources.• On-chip Analog Comparator.

COMPONENT EXPLANATION

CDS ELEMENTS (LDR)Some components can change

resistance value by changes in the amount of light hitting them.

Power supply It is a 3 terminal voltage regulators, which provide the required +5V. Regulators IC LM7805 (U3) provides regulated 5V power supplies, for Micro controller.

LM7805 (3 TERMINAL VOLTAGE REGULATER)

CRYSTAL OSCILLATORAn 11.0592MHz(X1) crystal provides a stable clock frequency.

SEVEN SEGMENT LED DISPLAY

• We can now interface a four digit 7-Seg to the micro controller.

• We use Scanning (Multiplex) Principle where one 7-seg is displayed after another but this process is very fast hence the flickering cannot be seen by human eye.

• When interfacing more than one 7-seg display ,the segment's( A to G) of all displays are connected together whereas their ANODE are switched ON one after another.

BLOCK DIAGRAM OF DIGITAL OBJECT COUNTER

Light Source

Laser torch or any other light source

LDR LDR

det

ecto

r

LM55

5

MIC

ROCO

NTR

OLL

ER

Power supply

LED Display

VCC

Q1 Q4Q3 Q2

COM

COM

COM

COM

12

131415

1716

18

9

8

19

11

7

R8

R11

R10

R9

R1 R2 R3 R4 R5 R6 R7

R12

P1.0/AIN0 P1.1/AIN1

P1.2P1.3P1.4P1.5P1.6P1.7

P3.7P3.5/T1P3.4/T0

P3.3/INT1

vcc

RST/VPP

P3.2/INT0

P3.0/RXD

P3.1/TXD

GND

XTAL

2

XTAL

1

4 5x1

c2 c3

2

3

R1

VCC

20U1

1

6

10

C1

SW1 RESET

VCC

R2

OUT

CV

5

7

R6DIS

CHG

GN

D

TRG

1R5 L

DR

R4

R3

VCC

4 8

U2

THR

VC

C

3

DIGITAL OBJECT COUNTER

in outGnd

D1

R7

PWR L1

C5C4 C6

VCCU3

9 TO 12 Dc in

CN3

• Digital object counter can be installed at the entry gate to count the total number of people entering any venue.

•For example, it can be used at the railway stations or bus stands to count the people arriving per day or week.

Application