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PUT COIN AND DRAW POWER

PUT COIN AND DRAW POWER

ABSTRACT

We are aware of the problems we are going

to face in the future due to lack of resources

which helps us in the production of

energy.So, if we save energy which is

available today we can reduce the problem

to some extent.We don’t keep that interest

on such problems but if we link energy with

money we can limit or control unnecesssary

wastage of energy.Keeping this factor in

mind this equipment has been designed.This

can be used for payloads like lamps and air

conditioners on a private electrical line; it is

also useful for paying guest houses, hotels

and trains.

This paper consists of the complete detaills

of construction,working and areas of

application of this equipment.

1. INTRODUCTION

This proposed project helps us to draw

power with the help of coins (say Rs.1/-

,Rs.2/-,Rs.5/-) like a payphone.

It is an automatic coin collection device for

payloads. This system makes use of a sensor

for detecting the coin and a micro controller

which counts the coins and shows the count

on a 7-Segment display.

When you close the load switch

provided in the circuit, the relay energizes to

connect the load and the display of count

starts decrementing, when the count

decrements to zero, the relay de-energizes to

disconnect the load, This pulse is used by

the micro controller to display the coin

count.

2. CONSTRUCTION

List of Hardware Components Used:

Semiconductors:

IC1 - NE556

dual timer

IC2 -

AT89C2051 micro controller

IC3 - CD45117

7-segment decoder/driver

IC4 - 7805 5V

regulator

IC5 - 7806 6V

regulator

T1, T2 - BC337

NPN transistor

D1-D5 - IN4007

rectifier diode

LED1-LED5 - 5mm LED

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DIS1 - LTS543

common-cathode 7-segment display

Resistors (all ¼ -watt, ±5% carbon):

R1 - 220Ω

R2 - 33kΩ

R3 - 220kΩ

R4, R7, R9, R25 - 330Ω

R5, R8 - 1kΩ

R6 - 10kΩ

R10-R16 - 270Ω

R17-R24 - 4.7kΩ

VR1 - 2.2MΩ-

preset

Capacitors:

C1, C7 - 10µF, 16V electrolytic

C2, C3 - 0.01µF

ceramic disk

C4 - 100µF,

16V electrolytic

C5, C6 - 33pF

ceramic disk

C8 - 1000pF,

35V electrolytic

C9, C10 - 0.1µF

ceramic disk

Miscellaneous:

X1 - 230V AC

primary to 9V, 500mA secondary

transformer

RL1 - 6V, 1C/O

relay

LDR1 - 10mm

S1 - push-to-on

switch

S2 - On/off

switch

- coin

selection

assembly

List of Softwares used:

Kiel Software

Preload Software

In this project we are going to use micro

controller which is the heart of the circuit

and Kiel n Preload soft ware’s to run and

dump the object file into the micro

controller.

The source program is written in Assembly

language and assembled using Keil

software. The source program has been well

connected for easy understanding. It works

as per the flow-chart.

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First, the program initializes the

microcontroller’s registers, then it checks

whether memory register is zero. If register

r3 is zero, it goes for coin detection. Else, it

proceeds to count update and display. Coin-

counter register r3 is incremented by five

after insertion of one coin. When the load

switch is closed. Port pin P#.1 goes low. Port P1.1 goes high to energies relay R1.1. Port pin

P3.2 goes low five times then display number decrements by one.

Schematic diagrams:

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5

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Description:

Fig. 1 shows the put coin and draw power

circuit. It comprises micro controller

AT89C2051 (IC2), dual timer NE556 (IC1),

7-segment decoder CD4511 (IC3),

regulators 7805 and 7806(IC4 and IC5), and

few discrete components.

LED1 is used as the light source for

light-dependent resistor LDR1, which is

made of cadmium sulphide and acts as the

coin detector. Resistor R1 limits the current

through LED1. The light from LED1 falls

continuously on LDR1, whose resistance

decreases with increase in the incident light

intensity.

The NE556 dual monolithic timing

circuit is a highly stable controller capable

of producing accurate time delays. It is

basically a dual NE555. In the tie delay

mode of operation, the time is precisely

controlled by an external resistor and

capacitor. The two timers operate

independently of each other, sharing only

Vcc and ground. The circuits may be

triggered and reset on falling waveforms

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. One timer of NE556 is used for coin

detection.

LDR1, connected at trigger pin6 of

IC1, offers low resistance when light is

falling on it and its trigger input goes low to

set the flip-flop and make out-put pin5 of

IC1 high.

When a coin is inserted, it interrupts

the light falling on LDR1, and trigger pin6

of IC1 goes high to make output pin 5 low.

This high-to-low pulse is used by the micro

controller to display the coin count.

Micro controller AT89C2051 is the

heart of the circuit. It is low-voltage, high-

performance, 8-bit microcontroller that

features 2kB of flash, 128 bytes of RAM,15

input/output(I/O) lines, two 16-bit

timers/counters, a five-vector two-level

interrupt architecture , a full duplex serial

port, a precision analogue comparator, on-

chip oscillator and clock circuitry. A 12MHz

crystal is used for providing the basic clock

frequency. All I/O pins are reset to ‘1’ as

soon as RST goes high. Holding RST pin

high for two machine cycles, while the

oscillator is running, resets the device.

Power- on reset id derived from resistor R6

and capacitor C7. Switch S1 is used for

manual reset.

Coin-detection output pin 5 of

NE556 is interfaced with port pinP.0 of the

microcontroller (IC2). The microcontroller

program counts the coins inserted and the

count is shown on a 7-segment display.

The ‘A’ through ‘D’ inputs of 7-

segment decoder IC3 are interfaced with

port pins P1.4 through P1.7 of IC2. IC3

accepts the BCD input and decodes it to

show on the 7-segment display. Coin

detection is also indicated by LED2, which

is connected to pin P3.7 of the

microcontroller.

After inserting the coin, close load

switch S2. Port pin P1.1 of the

microcontroller goes high to drive transistor

T2 into saturation. Relay RL.1 energizes and

LED3 glows to indicate that the load is now

switched on. D1 acts as a free-wheeling

diode.

As power is drawn by the load (pin

P1.1 high), the count shown on the 7-

segment display (DIS1) decrements. Port pin

P1.0 of the micro controller triggers the

second timer of NE556. When trigger pin 8

of NE556 goes low, its output pin 9 goes

high for a time period decided by preset

VR1 and capacitor C4. The high output of

timer is inverted by transistor T1 and fed to

port pin P3.2 of the microcontroller receives

five pulses (indicated by glowing of LED4).

Fig.2 shows the power supply circuit.

The 230V Ac mains is stepped down by

transformer X1 to deliver the secondary

output is rectified by full-wave bridge

rectifier comprising diodes D2 through D5,

filtered by capacitor C8 and then regulated

by IC’s 7805(IC4) and 7806(IC5).

Capacitors C9 and C10 bypass the ripples

present in regulated 5V and 6V power

supplies. LED acts as the power ‘on’

indicator and resistor R25 limits the current

through LED5.

3.WORKING

As actual size, single-side PCB for

put-coin-draw-power circuit is shown in

fig.3 a component layout in Fig.4. Write the

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circuit on the PCB and check for proper

connections using a multimeter.

Take a 10cm long, hallow,

rectangular cuboids of plastic in which a

coin can be inserted easily. Drill holes on

opposite sides at the centre and fixes LED1

and LDR1 such that these are placed faced

to face. Align LED1 and LDR1 such that

light from LED1 falls on LDR1 directly.

Cover the coin-collection assembly to

maintain darkness, leaving only coin-

insertion and coin-release holes open.

Extend LED1 and LDR1 from PCB to the

coin assembly using wires.

When a coin inserted into the coin-

collection assembly, light falling on the

LDR is blocked as the coin comes in

between LED1 and LDR1. LDR1 offers

high resistance in the absence of light and

this is detected by one timer of NE556 and

indicted by LED2.

You can insert up to 9 coins and this

count is displayed on DIS1. When you close

the load switch S2, the relay energizes and

load turns on. The count displayed on DIS1

starts decrementing after LED4 blinks five

times. The relay de-energizes to turn the

load off when the count displayed on DIS1

becomes zero. Load-‘on’ duration can be

adjusted using preset VR1. Never insert the

coin without pressing the reset switch S1.

Proposed Budget:

Approximately Rs.300/-

4.CONCLUSION

In the above specified way this equipment

can be constructed and can be used for

payloads like lamps and air conditioners on

a private electrical line; it is also useful for

paying guest houses, hotels and trains.

In this way we can save our energy and we

can use energy to our required extent and we

can limit the wastage of energy as it is

linked with money because we don’t prefer

to waste money to energy.

Further advancement can be made in this

equipment by keeping a load sensing device

and making corresponding changes in the

design.

REFERENCES

Electronics for you magazine, august 2009 copy

India edition, The 8051 micro controller, 3rd

edition, AYALA

Tata McGraw Hill, Embedded systems

(architecture, programming and design), Second

edition, RAJ KAMAL

Low price edition, an embedded software

primer, DAVID E.SIMON

Computers as components, principles of

embedded computer system design, WAYNE

WOLF

Tata McGraw Hill, ELECTRONIC DEVICES

AND CIRCUITS, MILLMAN HALKIAS

Linear integrated circuits, New age publications,

ROY CHOWDHARY

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CRM.ASHOK