Shri Vaishnav Institute of Technology & Science

PC Based Wirelesse Controll Appliances

Major project Submitted towards partial fulfillment of the

Degree of Bachelor of Engineering Year 2013-14

Department of Electrical and Electronics Engineering

Guided by Submitted byMiss Toshi Mandloi Akash Patidar (0802EX081004)

Dharmendra (0802EX081017) Prsson paul (0802EX091033) Satish Rathore (0802EX091046)

Shri Vaishnav Institute of Technology & Science, Indore

Department of Electrical & Electronics Engineering

CERTIFICATE

This is to certify that Akash Patidar,darmendra parmar,Prasson Paul andSatish Rathore have successfully and satisfactorily completed the projectwork titled “PC based wireless control appliances” towards the partialfulfillment of degree of Bachelor of Engineering in Electrical andElectronics awarded by Rajiv Gandhi Technical University Bhopalfor the academic year 2013-2014.

Project Guide Head of Department

Internal Examiner External Examiner

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Shri Vaishnav Institute of Technology & Science, Indore

Department of Electrical and Electronics Engineering

ACKNOWLEDGEMENT

We Acknowledge, with celerity and a deep sense of gratitude, the invaluable guidance given to us by Miss Toshi Mandloi (project guide) he suggestions and discussion were enlightened and a constant sourceof inspirations for us during our project work. We are indebted to her for helping us in acquiring knowledge of the practical applications of the concepts studied during the semester and answering to all our queries related to our project.

We express our heartfelt thanks to Mr. Anil K. Jain , Head of Department of Electrical and Electronics , for providing with an opportunity to do this project and giving invaluable encouragement in our endeavors .

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ABBREVIATION & NOTATIONS

HT12D Decoder ICHT12E Encoder ICCMOS Complementary Metal Oxide Semiconductor

EEPROM Electrically Erasable Programmable Read Only Memory

IC Integrated CircuitTE Transmitter Enable PinLCD Liquid Crystal DisplayMCU Microcontroller UnitPC Personal ComputerPCB Printed Circuit BoardRAM Random Access MemoryRF Radio FrequencyROM Read Only MemoryLED Light Emitting DiodeS1&S2 SwitchesAm Amplitude ModulatorIR InfraredGND Ground

Table 1 Abbrevation and Notation

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CONTENTS

Cover page I

Acknowledgement II

Certificate III

Abbreviations & Notations IV

Chapter N Subject Page No.

1. Design Objective...........................................,..........................06

2. Physical & Technical Specifications......................,,…..07-08

3. System Description.................................................,,,.......09-16

3.1 Introduction................................................,........................09

3.2 System Block Diagram & Description..........,,,…………10-13

3.3 PCB Construction.............................,,,,,.............................14

3.4 List of Components......................................,...,…………..15

3.5 Receiver&Transmitter Description..............,....................16

3.6 Flow chart of HT12D&HT12E……………,,…………..17&18

3.7 IC DM74LS138………………………………,,…………19

Application

Result

Future Suggestions & Enhancement

References

Annexure

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DESIGN OBJECTIVE

To design and implement PCB we have used eagle software. In this software we have first of all

design PCB layout on a glossy paper than layout applied on the PCB .

After the design of layout .

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PHYSICAL AND TECHNICAL SPECIFICATIONS

1] Physical Specifications:

1.a] Box Dimensions

Length: 25cm

Breadth: 12cm

Height: 06cm

1.b] PCB Dimensions

Transmitter Section: 10x 07cm

Receiving Section: 05 x 8 cm

1.c] Transformer

Length: 4 cm

Breadth: 2cm

Height: 4cm

1.d] PCB Material

Glass Epoxy Plate

Cu-Clad Plate

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2] Technical specifications:

2.1 Power Supply Requirements

2.1.1 Decoder IC HT12D 2.4V to 12V

2.1.2 Encoder IC HT12E 2.4Vto 12V

2.1.3 5V-12V single-supply operation

2.2 Power Source current drain for VCC of 5V and 12V

2.3 Operating Temperatures

2.3.1 Demultiplexer DM74LS138…………… 0C to 70

2.3.2 Storage Temperature ............................50C to 125C

2.3.3 Operating Temperature...........................20C to 75C

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SYSTEM DESCRIPTION

INTRODUCTION

The parallel port of the PC is a powerful platform of implementing projects dealing with the control

of the real world peripherals. It can be used to control home and other electronics appliances. The

computer program through the interface circuit controls the relays which in turn switch the appliance

on or off. Here we wirelessly control appliances from remote place by using the RF module. For this

“PC BASED WIRELESS CONTROL” system, Hardware as well as Software is required. The

parallel port of the PC used to control the appliances at the transmitter side. The RF interface is used

to control appliances within 150 meters range. The PC signals are transmitted from RF transmitter

&received by RF receiver

Remote control. For remote control, we have used the Holtek encoder-decoder pair of HT12E and

HT12D. Both of the seare 18-pin DIP ICs.  HT12E and HT12D are CMOS ICs with operating voltage range of 2.4V to 12V. Encoder HT12Ehaseight addresses and another four address/data lines. The data set on these twelve

lines (address and address/data lines) is serially transmitted when the transmitted able pin (TE) is taken low. The data output appears serially on DOUTpin.The data is transmitted four times in succession. It consists of differing lengths of positive pulses for ‘1’ and ‘0,’ the pulse-width for ‘0’ being twice the pulse width for ‘1.’ The frequency of these pulses may lie between 1.5 and 7 kHz depending on the resistor value between OSC1 and OSC2 pins.The internal oscillator frequency of decoder HT12D is 50 times the oscillator frequency of encoder HT12E. The values of the timing resistors connected between OSC1 and OSC2 pins of HT12E and HT12D, for a given voltage supply, can be found out from the graphs given in the data sheets of the respective chips. Here we have chosen the resistor values for approximately 3kHz frequency of the encoder (HT12E) and 150 kHz of the decoder (HT12D) at Vdd of 5V.The HT12D receives data from the HT12E on its DIN pin, serially. If the address part of the received data matches the levels on A0 through A7 pins four times in succession, the valid transmission (VT) pin goes high. The data on pins AD8 through AD11 of the HT12E appears on pins D8 through D11 of the HT12D. Thus the device acts as a receiver of the 4-bit data (16 possible codes) with 8-bit addressing (256 possible channels).Once the frequency of the pair is aligned, then on ground of any data pin on the

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encoder, LED1 on the decoder should light up. You can also check the data transfer on pins AD8through AD11, which is available on pins D8 through D11 of the decoder once TE pin is momentarily taken low by making it ground

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PCB LAYOUT OF TRANSMITTING SECTION

The RF transmitter TX-433 is AM/ ASK type and its circuit diagram(HT12E)

.

Signals from the Pc’s parallel port are interfaced to the RF transmitter through the RF encoder. The

encoder (HT12E) continuously reads the status of the opt coupler (MCT2E), passes the data to the

RF transmitter and the transmitter transmits the data. The RF receiver receives this data and gives it

to the RF decoder (HT12D). The decoder converts the single-bit data into four-bit data and presents

it to the decoder (74LS138). The output of the decoder controls the appliances with the help of flip-

flops (CD4013) and transistors. Now, relays perform the corresponding action i.e. switch the

appliances ‘on’ or ‘off.’

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PCB LAYOUT OF RECEIVING SECTION

The RF receiver receives this data and gives it to the RF decoder (HT12D).

The HT12D receives data from the HT12E on its DIN pin, serially. If the address part of the received data matches the levels on A0 through A7 pins four times in succession, the valid transmission (VT) pin goes high. The data on pins AD8 through AD11 of the HT12E appears on pins D8 through D11 of the HT12D. Thus the device acts as a receiver of the 4-bit data (16 possible codes) with 8-bit addressing (256 possible channels).

.

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PCB Construction

Fig.5:An actual-size, single-side PCB forthe transmitter circuit

Fig.7: Actual-size, single-side PCB forthe receiver and logic control section(on the left side of dotted line)

Fig.9: Actual-size, single-side PCB for the relay driver section(on the right side of dotted line)

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List of Components

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Transmitter.

Fig.3 shows the transmitter circuit for PC-based wireless appliance control. The receiver address to be transmitted can be set with the help of an 8-way DIP switch (DIP-SW1). If any switch is open the pin connected to that switch is at logic 1, and if it is closed the respective pin is at logic 0. The data pins are pulled high via resistors R2 through R5.

When pin 2 of the parallel port goes high, the internal LED of the optocoupler(MCT2E) glows to drive the internal phototransistor into saturation and its pin 5 goes low.

Pin 10 (AD8) of HT12E goes low through pin 5 of MCT2E and a ‘0’ is sent at that data position, while other data pins represent the logic-1 state. The logic circuitry at the receiver-decoder end decodes the data appropriately for controlling the switch of an appliance.

Receiver-cum-decoder.

Fig.4 shows the receiver circuit for PC-based wireless appliance control. Assuming that an identical address is selected on the encoder and decoder, when anyone of data pins D0 through D3 of the PC’s parallel port on the transmitter is high, the corresponding data pin of the demodulator goes low at the decoder (HT12D). The data outputs (D8 through D11) of HT12D are connected to inverters N1 through N4. The output of inverters N1, N2 and N3 are connected to address inputs A, B and C of decoder 74LS138, respectively. The outputs of inverters N4 and N5 enable the decoder to drive the flip-flop (CD4013).

IC CD4013 is configured as a toggle flip-flop. The output of the flipflop (IC9(A)) drives transistor T2 into saturation and relay RL1 energises. D7 through D14 are used as free-wheeling diodes. The relay contacts are used for  appliances. 

When any data is received, the valid transmission pin (VT) goes high to drive the transistor into saturation and LED1 lights up.

RF transmitter and receiver

The RF transmitter and receiver modules from Alpus India, Mumbai, have been employed for RF remote control.

The RF transmitter TX-433 is AM/ ASK type. It features:

1. 5V-12V single-supply operation2. On-off keying (OOK)/amplitude shift keying (ASK) data format3. Up to 9.6kbps data rate4. +9dBm output power (a range of about 200 metres)5. SAW-based architecture and For the antenna, a 45cm wire is adequateThe output power and current drain for VCC of 5V and 12V, respectively.

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Flow chart of IC HT12D

The 212 decoders are a series of CMOS LSIs for remote control system applications. They are paired withHoltek s212 series of encoders (refer to theencoder/decodercross reference table). For proper operation, apair of encoder/decoder with the same number of address Resand data format shouldbechosen.The decoders receive serial addresses and data from programmed 212 series of encoders that are transmittedby a carrier using an RFor an IR transmission medium.They compare the serial input data three times continuouslywith their local addresses. If no error or unmatched codes are found, the input data codes aredecoded and then transferred to the output pins. The VTpin also goes high to indicate a valid transmission.The 212 series of decoders are capable of decoding information that consist of N bits of address and 12_Nbits of data. Of this series, the HT12D is arranged to provide8 address bits and 4 data bits, and HT12F is used todecode 12 bits of address information.

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Flow Chart of IC HT12E

1~

~ `1

The 212 encoders are a series of CMOS LSIs forremote control system applications. They arecapable of encoding information which consists of N address bits and 12_N data bits. Each address/data input can be set to one of the twologic states. The programmed addresses/dataare transmitted together with the header bitsvia an RF or an infrared transmission mediumupon receipt of a trigger signal. The capabilityto select a TE trigger on the HT12E or a DATAtrigger on the HT12A further enhances the applicationflexibility of the 212 series of encoders.The HT12A additionally provides a 38kHz carrierfor infrared systems

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IC DM74LS138 General Description

These Schottky-clamped circuits are designed to be usedin high-performance memory-decoding or data-routingapplications, requiring very short propagation delay times.In high-performance memory systems these decoders canbe used to minimize the effects of system decoding. Whenused with high-speed memories, the delay times of thesedecoders are usually less than the typical access time ofthe memory. This means that the effective system delayintroduced by the decoder is negligible.The DM74LS138 decodes one-of-eight lines, based uponthe conditions at the three binary select inputs and thethree enable inputs. Two active-low and one active-highenable inputs reduce the need for external gates or inverterswhen expanding. A 24-line decoder can be implementedwith no external inverters, and a 32-line decoderrequires only one inverter. An enable input can be used asa data input for demultiplexingapplications.The DM74LS139 comprises two separate two-line-to-fourlinedecoders in a single package. The active-low enableinput can be used as a data line in demultiplexing applications.All of these decoders/ demultiplexers feature fully bufferedinputs, presenting only one normalized load to its drivingcircuit. All inputs are clamped with high-performanceSchottky diodes to suppress line-ringing and simplify systemdesign.

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Connection Diagram

Software

The source program for PC-based wireless appliance control is written in Visual Basic. To use the software on Win XP platform, the input32.dll file should reside in the same folder as the .exe file of the program. The main screen for PC-based wireless appliance control is shown in Fig.11.

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Fig.11: Main screen on PC

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Application

Now in our day to day life the PC plays such a vital role that without which the life would have been difficult in every aspect. For example in banks, firms, industries, etc PCs are needed to handle more than one operations. More and more PC based product sare being made and used in our day to day life. One of the project which will control the appliances through PC is done here to make our life simpler and we can control the appliances sitting at single location through PC. This project can be used where the control of different appliances is to be done with PC i.e. in some industries and firms in order to µon and off the different mechanisms and machines. This can also be used in some offices where different appliances like fans, tube lights, etc are needed to switch off and µon according to the need. Also this can also be used at home as comfort of life are increasing day to day and every electronic appliances are being remote operated so this can be used so that different appliance can be controlled with the help of PC .There is no need to go at different places to switch the appliances on and off, instead many of the appliances which are needed to on and off at regular interval can be interfaced with this circuit and we can control all the appliances from a single locatio

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RESULT

We have successfully developed a front panel in visual basic in software part and had

written a code in order to interface our transmitter circuit with PC. Then we interfaced

transmitter, receiver and relay driver circuit. Also we had connected the power supply

and given required voltages and have arranged the things in a manner they should be and

had run the project successfully. the arrangements we have done in order to run the project and

here we had only connected one device i.e we have only controlled a single device

LED. In the similar manner we can connect other devices so that it can be controlled with the help

of PC

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SUGGESTIONS & FUTURE ENHANCEMENTS

a) The aim of home automation is to control home devices from a central control point. In this paper, we present the design and implementation of a low cost but yet flexible and secure Internet based home automation system. The communication between the devices is wireless. The protocol between the units in the design is enhanced to be suitable for most of the appliances. The system is designed to be low cost and flexible with the increasing variety of devices to be controlled.

b) PC-Communication could be added with an aim to allow dumping of data

from device to compute where it can be stored with more fidelity and user

friendly interface.

c) Signals from the PC parallel port are interfaced to the RF transmitter through

the RF encoder. The encoder continuously reads the status of the opto-coupler

passes the data to the RF transmitter & the transmitter transmits the data.

The RF receiver receives this data & gives it to the RF decoder. The

decoders converts the signals/bit data into 4 bit data & present it to the

multiplexer decoder.The output of decoder controls the appliances with the

help of flip-flop & transistors now relay performs the corresponding action so

that switch the appliances on or off .

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REFERENCES

ANSHUMAN BEZBORAH AND ARUNAV KUMAR SINHA

1. Microcontroller Projects in C for 8051”

2. www.efy.com

3. www.electronics4you.com

4. www.efy.com/mag2009/intr

Pc based wireless home appliances control

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