it will open automatically after sensing of a person

1. Automatic main gate controller
Contents
1. ABSTRACT
2. INTRODUCTION
3. DESIGN PRINCIPLE
4. CIRCUIT DESCRIPTION
Power Supply.
Light detector
Mother board
Bi-directional Motor Driver.
5. FUTURE EXPANSION
6. CONCLUSION

2. Description
In this project work, we attempt to construct a small and simple model of and
Automatic Gate System, which uses a simple motor operated gate, which uses
for car power window and circuitry to move the gate. The primary aim of this
project is to learn in details about how the automatic gate system works and to
understand to concepts involved. The secondary aim is to fabricate a simple
model to show how the system works. Although we had many hiccups during
the fabrication of the gate but we were able to learned a lot from this project
such as team work, innovation, the skill of arc welding and the ability to put into
practice what we have learned to achieve our desired outcome.

3. Design principle
The system is designed with one entry/exit gate. The entry gate will open only
when there is a person will be in front of the gate. There are Infra red
transmitter (Tx) and Infrared receiver (Rx) before and after each gate which
detect the arrival and departure of person and operate the Gates by issuing
control signal from the microcontroller. The microcontroller output is given to
the bidirectional motor driver to gate open close. The functional block diagram
is as shown in the above figure, it comprises Two IR transmitter, Two IR
detector modules, microcontrollers, 2 input NOR gate and a bidirectional
motor driver.

4. Block

5. Circuit description
Here 230V, 50 Hz ac signal is given as input to the primary of the
transformer and the secondary of the transformer is given to the bridge
rectification diode. The o/p of the diode is given as i/p to the IC regulator
(7805 &7812) through capacitor (1000mf/35v). The o/p of the IC
regulator is given to the LED through resistors.

6. Circuit
1k
0-12/1A
230V50Hz
POWER SUPPLY
2.2K
LED
LED
IN 4007 * 4 1000uF/35V
+5V
7812 +12V
7805

7. Light detector
The LDR sensing circuit is configured as a voltage divider circuit. At normal
condition, the source light filling on the LDR its resistance increases, so the
voltage decreases which is given to the non-inverting terminal of the op-amp
which is nothing but the reference voltage and the inverting terminal is
connected to a variable resistor (10k) through a Vcc. Here the op-amp is
configured as comparator, comparator is nothing but compares the two
voltages i.e. non-inverting to the inverting terminal. If the non-inverting (-)
terminal is greater than the inverting (+) terminal, the output of the
comparator goes to the –Vsat=0. Similarly, if the inverting terminal is greater
than the non-inverting terminal, the output of the comparator goes to the
+Vsat=1.

8. Circuit
BC547
68k
10k
10k
LED
330e
VCC
VCC
10k
LDR
-
+
LM393
3
2
1
84
15k

9. Mother board
The motherboard of this project is designed with a MSC –51 core
compatible micro controller. The motherboard is designed on a
printed circuit board, compatible for the micro controller. This board
is consisting of a socket for micro controller, input /output pull-up
registers; oscillator section and auto reset circuit.

10. Auto reset and crystal Circuit
RST
10uF
22pF
22pF
8.2k
4 - 12Mhz
VCC=+5vdc
AT89C51
9
18
19
29
30
31
1
2
3
4
5
6
7
8
21
22
23
24
25
26
27
28
10
11
12
13
14
15
16
17
39
38
37
36
35
34
33
32
RST
XTAL2
XTAL1
PSEN
ALE/PROG
EA/VPP
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
P2.7/A15
P3.0/RXD
P3.1/TXD
P3.2/IN T0
P3.3/IN T1
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
P0.0/AD0
P0.1/AD1
P0.2/AD2
P0.3/AD3
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
MICROCONTROLLER

11. The auto reset circuit is a RC network as shown in the mother board
circuit diagram. A capacitor of 1-10mfd is connected in series with a 8k2
resister the R-C junction is connected to the micro controller pin –9
which is reset pin. The reset pin is one when ever kept high (logic 1) the
programme counter (PC) content resets to 0000h so the processor starts
executing the programme. From that location. When ever the system is
switched ON the mother board gets power and the capacitor acts as short
circuit and the entire voltage appears across the resistor, so the reset pin
get a logic 1 and the system get reset, whenever it is being switched ON.
Auto reset circuit

12. Crystal oscillator
The 8051 family microcontroller contains an inbuilt crystal oscillator, but
the crystal has to be connected externally. This family of microcontroller
can support 0 to 24MHz crystal and two numbers of decoupling
capacitors are connected as shown in the figure. These capacitors are
decouples the charges developed on the crystal surface due to
piezoelectric effect. These decoupling capacitors are normally between
20pf to 30pf. The clock generator section is designed as above,

13. Pull-up resistors
The PORT0 and PORT2 of the MCS-51 architecture is of
open collector type so on writing logic 0 the pins are
providing a perfect ground potential. Where as on writing
logic 1 the port pins behaves as high impedance condition
so putting a pull-up resister enables the port to provide a
+5volt (logic 1). Port1 and Port3 are provided with
internal pull-ups. A pull-up resister is normally a 10K
resistance connected from the port pin to the Vcc (+5) volt.

14. Circuit
AT89C51
9
18
19
29
30
31
1
2
3
4
5
6
7
8
21
22
23
24
25
26
27
28
10
11
12
13
14
15
16
17
39
38
37
36
35
34
33
32
RST
XTAL2
XTAL1
PSEN
ALE/PROG
EA/VPP
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
P2.7/A15
P3.0/RXD
P3.1/TXD
P3.2/INT0
P3.3/INT1
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
P0.0/AD0
P0.1/AD1
P0.2/AD2
P0.3/AD3
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
10k
PORT-0
VCC=+5V

15. Bi-directional motor driver
Here we drive the PMDC motor in both the direction using transistor h-
bridge of ICs l293d . An H-bridge is an arrangement of transistors that
allows a circuit full control over a standard electric DC motor. That is, with
an H-bridge a microcontroller, logic chip, or remote control can
electronically command the motor to go forward, reverse, brake, and coast.

16. Circuit
5
6
16
9
L 293D
11
14
4
Bi-directional motor driver
M
12
15
Vcc
M
1
3
7 D
VCC
8
A
13
B 10
C2

17. Future expansion
The present project is designed for only automatic gate open close
system. Further it can be expanded for visitor counter system. And
also program using password based door open close system. This
design is a application of simple digital IC. This same design can be
computed using Microcontroller and many more facilities can be
incorporated in it.

18. Conclusion
The system is designed in the laboratory and tested in the
laboratory condition. It is observed that the system is
operating satisfactorily with a very minimum error which
is quit less than the experimental tolerance level. The
design is quite stable and economical.

19. --------------- Thank you ---------------