17-01-2010, 12:04 AM
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INTRODUCTION
Background
Before giving any explanation of INTERACTIVE VOICE RESPONSE SYSTEM this project mainly depends on the embedded system and microcontroller.
1.1 Basics of embedded system:
An embedded system is a special-purpose system in which the computer is completely encapsulated by or dedicated to the device or system it controls. Unlike a general-purpose computer, such as a personal computer, an embedded system performs one or a few predefined tasks, usually with very specific requirements. Since the system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product. Embedded systems are often mass-produced, benefiting from economies of scale.
Personal digital assistants (PDAs) or handheld computers are generally considered embedded devices because of the nature of their hardware design, even though they are more
Examples of Embedded Systems:
¢ Avionics, such as inertial guidance systems, flight control hardware/software and other integrated systems in aircraft and missiles
¢ Cellular telephones and telephone switches
¢ Engine controllers and antilock brake controllers for automobiles
¢ Home automation products, such as thermostats, air conditioners, sprinklers, and security monitoring systems
¢ Handheld calculators
¢ Handheld computers
¢ Household appliances, including microwave ovens, washing machines, television sets, DVD players and recorders
¢ Medical equipment
¢ Personal digital assistant
¢ Videogame consoles
¢ Computer peripherals such as routers and printers.
¢ Industrial controller for remote machine operation
1.2 Introduction about micro controller:
A Micro controller consists of a powerful CPU tightly coupled with memory, various I/O interfaces such as serial port, parallel port timer or counter, interrupt controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog converter, integrated on to a single silicon chip. If a system is developed with a microprocessor, the designer has to go for external memory such as RAM, ROM, EPROM and peripherals. But controller is provided all these facilities on a single chip. Development of a Micro controller reduces PCB size and cost of design.
One of the major differences between a Microprocessor and a Micro controller is that a controller often deals with bits not bytes as in the real world application. Intel has intro uced a family of Micro controllers called the MCS-51.
1.3 Introduction to IVRS
INTERACTIVE VOICE RESPONSE SYSTEM (also known as Computer Telephony Integration Systems) are gaining wide acceptance in a large number of application areas like Department of Telecom, airlines / Railway reservation systems, Banks and Various other organizations. IVR systems provide access to computer databases through normal telephones. A user can access a remote computer data base by dialing a specified IVR system number and obtain the required information by dialing the specified digits as informed by the computer. The desired information can be recorded and stored in the PC using a microphone, which will be informed to the user on dialing the specified Number.
SYSTEM APPLICATIONS
¢ Airline / Railways / Bus Stations Arrival/Departure timings Reservation Status Telebooking.
¢ Banks/Financial Institutions Auto attendant Account status Balance Amount in the account Loan information etc.
¢ Telemarketing Market divisions of Industrial units
¢ Telesurvey Market research organizations
¢ Hotels Auto attendant Reservation Room availability status
¢ Retail stores Teleordering / Teleinformation
¢ Stock market Shares information
¢ Voice messaging Voice Mail
1.4 FEATURES
Wireless operation of electronic switches.
Interactive system
Acknowledgment is provided
On/off all electronic appliances
Accessing more number switches with ease
Security code to activate the system
User friendly system Wireless operation of electronic switches.
1.5 Block diagram
1.6 Block diagram description:
1.6.1 Hardware components:
Power supply
Micro controller
DTMF decoder
Voice processing unit
devices
1.6.2 Power supply:
In this system we are using 5V power supply for microcontroller of Transmitter section as well as receiver section. We use rectifiers for converting the A.C. into D.C and a step down transformer to step down the voltage. The full description of the Power supply section is given in this documentation in the following sections i.e. hardware components.
1.6.3 Microcontroller (89S51):
In this project work the micro-controller is playing a major role. Micro-controllers were originally used as components in complicated process-control systems. However, because of their small size and low price, Micro-controllers are now also being used in regulators for individual control loops. In several areas Micro-controllers are now outperforming their analog counterparts and are cheaper as well.
The purpose of this project work is to present control theory that is relevant to the analysis and design of Micro-controller system with an emphasis on basic concept and ideas. It is assumed that a Microcontroller with reasonable software is available for computations and simulations so that many tedious details can be left to the Microcontroller. The control system design is also carried out up to the stage of implementation in the form of controller programs in assembly language OR in C-Language.
1.6.4 DTMF (DUAL TONE MULTI FREQUENCY):
A DTMF is used to decode the frequency and to give the instructions to microcontroller.
1.6.5 Devices:
Here devices or Appliances are interfaced with the micro controller .based on the input instruction the particular appliance is operated.
1.6.6 Voice processing unit:
Voice processing unit is used to give voice instructions, which is done with the help of voice IC.
Chapter 2
SCHEMATIC
2.1 Schematic Explanation:
The main aim of this power supply is to convert the 230V AC into 5V DC in order to give supply for the TTL. This schematic explanation includes the detailed pin connections of every device with the microcontroller.
This schematic explanation includes the detailed pin connections of every device with the microcontroller. The pin no 23 and 25 are grounded in such a way that voice record and play back will be possible. The mobile will be connected to the speaker pins.
Let us see the pin connections of each and every device with the microcontroller in detail.
2.1.1 Power Supply:
In this process we are using a step down transformer, a bridge rectifier, a smoothing circuit and the RPS.
At the primary of the transformer we are giving the 230V AC supply. The secondary is connected to the opposite terminals of the Bridge rectifier as the input. From other set of opposite terminals we are taking the output to the rectifier.
The bridge rectifier converts the AC coming from the secondary of the transformer into pulsating DC. The output of this rectifier is further given to the smoother circuit which is capacitor in our project. The smoothing circuit eliminates the ripples from the pulsating DC and gives the pure DC to the RPS to get a constant output DC voltage. The RPS regulates the voltage as per our requirement.
2.1.2 Microcontroller:
The microcontroller AT89S51 with Pull up resistors at Port0 and crystal oscillator of 11.0592 MHz crystal in conjunction with couple of capacitors of is placed at 18th & 19th pins of 89S51 to make it work (execute) properly.
2.1.3 Motor:
The motor is one of the output devices. This is connected to the port P3.6 of the Microcontroller through the transistor circuitry as shown in the above schematic.
2.1.4 Device:
Here the device to be controlled is connected to the port p3.7 of the micro controller by using relays.
2.1.5 DTMF:
This is nothing but a Dual Tune Multiple Frequency. This receives the signals from the mobile and sends it to the microcontroller.
2.1.6 Voice decoder:
This device will receive the signal of human voice through mike. It is having 28 pins on its IC. It consists of 8 message lines (or channels) to which we can give a voice message and it can operate in any one of two modes (recording and playback).
The supply pins are connected to power supply circuit. Analog (AGND) and digital ground (DGND) pins of voice decoder IC are connected to VSS of power supply. Analog power supply
2.2 Schematic Diagram
Figure 2 schematic diagram
2.3 PROJECT IMPLEMENTATION
Ivrs idea is taken from Computer Telephony Integration Systems. Ivrs mainly consists of five blocks. First block is power supply, it is constant 5 volts dc power supply taking input from 230 volts AC. It is converted 5 volts Dc by using a step down transformer, a bridge rectifier, a smoothing circuit and the RPS. 5 volts DC is connected VCC ( pin 40 of microcontroller ).
2.3.1 INTERFACINGS OF DTMF
User mobile phone generates different frequency when we dial the numbers. These frequencies are transmitted to mobile phone which is connected kit which is already in auto answer mode. It is interfaced with help of headset connected to the input pins (pin 1&2.
Figure 3 INTERFACING OF DTMF TO MOBILE
Figure 4 DIAL TONE FREQUENCY STANDARD
For example to activate ivrs we have to dial ˜0™. After dialling ˜0™ a dual tone frequency [1336+941] is sent. Functionality of dtmf is to decode dual tone frequency to digital data.
Figure 5 INTERFACING OF DTMF WITH MICROCONTROLLER
Digital output is taken from pins (pin 11 to 14) of dtmf which are connected to port 2 (p2.0 to p2.3) of microcontroller.
Functionality of DTMF block it is an IC DTMF8870 which converts dual tone frequency given by mobile phone to digital information. It is connected in single ended input configuration. In a single-ended configuration, the input pins are connected as shown in the Single - Ended Input with the op-amp connected for unity gain and VREF biasing the input at 1/2VDD. The Differential Input Configuration in FIGURE below permits gain adjustment with the feedback resistor R5. We have steering circuit connected to st/et and est pin to select minimum time period of a valid signal. We have grounded pin 5& 6 because we are not using extra keys and power down mode. Why I have selected DTMF8870 because it most commonly used and successful worldwide.
Figure 6 single ended input configuration
F LOW F HIGH Key (ref.) OE Q4 Q3 Q2 Q1
697 1209 1 H 0 0 0 1
697 1336 2 H 0 0 1 0
697 1477 3 H 0 0 1 1
770 1209 4 H 0 1 0 0
770 1336 5 H 0 1 0 1
770 1477 6 H 0 1 1 0
852 1209 7 H 0 1 1 1
852 1336 8 H 1 0 0 0
852 1477 9 H 1 0 0 1
941 1336 0 H 1 0 1 0
L = logic low, H = logic high, Z = high impedance
Table 1 M8870 PIN FUNCTION
Figure 7 TIMING DIAGRAM OF 8870
Explanation of Events
(A) Tone bursts detected, tone duration invalid, outputs not updated.
(B) Tone #n detected, tone duration valid, tone decoded and latched in outputs.
© End of tone #n detected, tone absent duration valid, outputs remain latched until next valid tone.
(D) Outputs switched to high impedance state.
(E) Tone #n + 1 detected, tone duration valid, tone decoded and latched in outputs (currently high impedance).
(F) Acceptable dropout of tone #n + 1, tone absent duration invalid, outputs remain latched.
(G) End of tone #n + 1 detected, tone absent duration valid, outputs remain latched until next valid tone.
Explanation of Symbols
VIN DTMF composite input signal.
EST Early steering output. Indicates detection of valid tone frequencies.
St/GT Steering input/guard time output. Drives external RC timing circuit.
Q1 - Q4 4-bit decoded tone output.
STD Delayed steering output. Indicates that valid frequencies have been present/absent for the required guard time, thus constituting a valid signal.
OE Output enable (input). A low level shifts Q1 - Q4 to its high impedance state.
Third block is microcontroller block in this block we are using AT89S51. We have programmed it embedded c software. A Micro controller consists of a powerful CPU tightly coupled with memory, various I/O interfaces such as serial port, parallel port timer or counter, interrupt controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog converter, integrated on to a single silicon chip.
If a system is developed with a microprocessor, the designer has to go for external memory such as RAM, ROM, EPROM and peripherals. But controller is provided all these facilities on a single chip
Functioning of microcontroller, it takes input from DTMF ic in form of parallel bits from pins (pin 11 to 14) of dtmf which are connected to port 2 (p2.0 to p2.3) of microcontroller and controls the output devices like voice processing unit and output devices.
For example, to start IVRS system we have to dial ˜0™. That means we are giving DTMF ˜1010™ parallel bits has input to microcontroller. It takes that parallel data and computes the data with stored instruction. Our given instruction is if input is 1010 then set 1.1 of port1 to active low which is connected to m1 message (pin 1) of APR9600. Since m1 is given active low signal it plays recorded voice signal.
After listening to message signal, we come to know that to ˜on™ light we have to dial ˜1™.then we have to dial ˜1™ to light that means we are giving an ˜0001™ has input to the microcontroller .as per given instruction it makes 3.7 active high. Which activate transistor gate and ˜on™ light.
Reasons for selecting AT89S51 are it contains watchdog timer circuit internally and logic high is up to 5.5volts so that it can have protection Microcontroller from deflection in voltage.
Fourth bock is voice processing block in which we have a voice processing IC APR9600. This device will receive the signal of human voice through mike. It is having 28 pins on its IC. It consists of 8 message lines (or channels) to which we can give a voice message and it can operate in any one of two modes (recording and playback).
The supply pins are connected to power supply circuit. Ana log (AGND) and digital ground (DGND) pins of voice decoder IC are connected to VSS of power supply. Ana log power supply. Here it is used has simple recorded voice playing circuit. This is capable of storing 60 seconds voice.
2.3.2INTERFACINGS OF APR9600 VOICE PROCESSING IC
Figure 8 INTERFACING OF APR9600 WITH MICROCONTROLLER
Pin 1 /m1 of APR9600 is connected to port 1.0 of microcontroller.
Figure 9 INTERFACING OF APR9600 WITH MOBILE PHONE
Pins (14 & 15) sp+ and sp- are connected to mobile phone voice cable.
Pin 1 /m1 of APR9600 is connected port 1(p1.0) and pins (14 & 15) sp+ and sp- are connected to mobile phone voice cable. Whenever microcontroller applies input logic high to /m1 pin them ic will play the recorded voice signal. APR9600 is selected our requirement is only 60 seconds voice recording only so we are using this particular IC. refer to figure 18 for pin diagram.
Table 2 PIN FUNCTION OF APR9600
It operates in different modes they are
Table 3 MODES OF APR9600
MSEL1 MSEL2 -M8 Function Keys Functions
0 0 0 or 1 -M1, -M2 to select 1st and 2nd sound tracks. CE to stop Parallel mode, 2 sections, 30 seconds for each
1 0 0 or 1 -M1 to “M4 to select a sound track, CE to stop Parallel mode, 4 sections, 15 seconds for each
1 1 1 -M1 to “M8 to select a sound
track, CE to stop Parallel mode, 8 sections, 7.5 seconds for each
1 1 1 -M1 to “M8 to select a sound
track, CE to stop Pressing and hold down a key from “M1 to M8 to play the selected sound track repeatedly
0 0 1 -M1 and CE Serial mode, allow up to 256 sound tracks to be
recorded and played. Sound tracks are played from
1st to N in order after “M1 is toggled. Press CE to
play from the 1 st sound track.
0 0 0 -M1,-M2 and CE Serial mode, Press “M1 to replay one sound track.
Toggle “M2 once to move to the next sound track.
Press CE to play sound from the 1 st sound track
Here we are using serial mode of operation because here we will play single voice. So we have selected last mode of operation. Selecting of 7th pin resistance depends on time period of the signal.
Table 4 OSCR RESISTACES AND ITS SAMPLING FREQ.
Here we are using 40 seconds of voice message so we have selected 38k resistance
Replay sound tracks with forward control
Now make RE=1 (switched to Left-hand side of the mode selection switch) while keep other
Switches at the same location. Toggle “M1 (press key and release) causes the 1st sound track to be played once. Toggle “M1 again and again will still play the 1st sound track. Once “M2 is toggled, the sound track counter is incremented and the next sound can be played. Press CE to reset the sound track counter to zero.
Fifth block is output devices. In my project I am using two devices, one is dc fan which is connected port 3.6 (pin 16) and another 230 volts Ac bulb which is connected to port 3.7.
2.3.3 INTERFACING OF OUTPUT DEVICES
Figure 10 INTERFACING OF OUTPUT DEVICES
INTERFACING OF DC MOTOR
It is connected to port 3.6 which is bit wise opera table. When microcontroller makes 3.6 pin high logic level voltage. This is connected to base of transistor. Transistor acts as short circuit which forms a closed loop. So voltage is applied to dc motor.
Figure 11 INTERFACING OF DC MOTOR
INTERFACING OF LIGHT
It is connected to port 3.7 which is bit opera table .here port 3.7 is connected to relay by which it is Ëœonâ„¢ and Ëœoffâ„¢ operation is performed.
Figure 12 INTERFACING OF LIGHT
FLOW CHART OF PROGRAM TO ËœONâ„¢ AND ËœOFFâ„¢ LIGHT
Figure 13 FLOW CHART OF PROGRAM
SOURCE CODE
//adding the header files
#include<reg51.h>
//declaring the DTMF connections
sbit d0 = P2^0;
sbit d1 = P2^1;
sbit d2 = P2^2;
sbit d3 = P2^3;
sbit clk = P2^4;
//declaring the outputs
sbit relay = P3^7;
sbit motor = P3^6;
//declaring the voice connections
sbit msg = P1^0;
//starting the main program
void main()
{
while(1)
{
{
if(d3 == 1 && d2 == 0 && d1 == 1 && d0 == 0)
{
msg = 0;
while(1)
{
while(clk)
{
if(d3 == 0 && d2 == 0 && d1 == 0 && d0 == 1)
{
relay = 1;
}
if(d3 == 0 && d2 == 0 && d1 == 1 && d0 == 0)
{
relay = 0;
}
if(d3 == 0 && d2 == 0 && d1 == 1 && d0 == 1)
{
motor = 1;
}
if(d3 == 0 && d2 == 1 && d1 == 0 && d0 == 0)
{
motor = 0;
}
if(d3 == 1 && d2 == 0 && d1 == 1 && d0 == 0)
msg = 0;
}
}
}
}
END OF CHAPTER 2
Chapter 3
HARDWARE COMPONENTS
3.1 HARDWARE DESIGN
3.1.1 Introduction
In this chapter we are going to cover all parts of Interactive Voice Response System (IVRS) in detailed manner and their functions in brief. Here we are more interested about the Microcontroller since it is the heart of the project. So the complete architecture is explained and also significance of the Microcontroller.
Hardware components:
1. power supply
2. Micro controller
3. DTMF decode
4. Voice IC
5. Devices
3.1.2 MICRO CONTROLLER (AT89S51)
3.1.2.1 Introduction
A Micro controller consists of a powerful CPU tightly coupled with memory, various I/O interfaces such as serial port, parallel port timer or counter, interrupt controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog converter, integrated on to a single silicon chip.
If a system is developed with a microprocessor, the designer has to go for external memory such as RAM, ROM, EPROM and peripherals. But controller is provided all these facilities on a single chip. Development of a Micro controller reduces PCB size and cost of design.
One of the major differences between a Microprocessor and a Micro controller is that a controller often deals with bits not bytes as in the real world application.
Intel has introduced a family of Micro controllers called the MCS-51.
Figure 14 micro controller
3.1.2.2 Features:
¢ Compatible with MCS-51® Products
¢ 4K Bytes of In-System Programmable (ISP) Flash Memory
“ Endurance: 1000 Write/Erase Cycles
¢ 4.0V to 5.5V Operating Range
¢ Fully Static Operation: 0 Hz to 33 MHz
¢ Three-level Program Memory Lock
¢ 128 x 8-bit Internal RAM
¢ 32 Programmable I/O Lines
¢ Two 16-bit Timer/Counters
¢ Six Interrupt Sources
¢ Full Duplex UART Serial Channel
¢ Low-power Idle and Power-down Modes
3.1.2.3 Description
The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of in-system programmable Flash memory. The device is manufactured using Atmelâ„¢s high-density nonvolatile memory technology and is compatible with the industry- standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S51 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.
Block diagram:
Figure 15 block diagram of micro controller
Pin diagram:
Figure 16 pin diagram of micro controller
3.1.2.4 Pin Description
VCC - Supply voltage.
GND - Ground.
Port 0:
Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull-ups are required during program verification.
Port 1:
Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 1 also receives the low-order address bytes during Flash programming and verification.
Table 5 PORT 1
Port 2:
Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.
Port 3:
Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control signals for Flash programming and verification. Port 3 also serves the functions of various special features of the AT89S51, as shown in the following table.
Table 6 PORT3
RST:
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. This pin drives High for 98 oscillator periods after the Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled.
ALE/PROG:
Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.
PSEN:
Program Store Enable (PSEN) is the read strobe to external program memory. When the AT89S51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.
EA/VPP:
External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.
XTAL1:
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
XTAL2:
Output from the inverting oscillator amplifier.
Oscillator Characteristics:
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figs 6.2.3. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 6.2.4.There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.
3.1.3 DTMF (DUAL TONE MULTI FREQUENCY)
The M-8870 is a full DTMF Receiver that integrates both band split filter and decoder functions into a single 18-pin DIP or SOIC package. Manufactured using CMOS process technology, the M-8870 offers low power consumption (35 mW max) and precise data handling. Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code. External component count is minimized by provision of an on-chip differential input amplifier, clock generator, and latched tri-state interface bus. Minimal external components required include a low-cost 3.579545 MHz color burst crystal, a timing resistor, and a timing capacitor.
The -8870 provides a power-down option which, when enabled, drops consumption to less than 0.5 mW. The M-8870-02 can also inhibit the decoding of fourth column digits
3.1.3.1 Features
¢ Low Power Consumption
¢ Adjustable Acquisition and Release Times
¢ Central Office Quality and Performance
¢ Power-down and Inhibit Modes (-02 only)
¢ Inexpensive 3.58 MHz Time Base
¢ Single 5 Volt Power Supply
¢ Dial Tone Suppression
Pin diagram:
Figure 17 pin diagram of m8870
BLOCK DIAGRAM:
Figure 18 functional block diagram of m8870
3.1.3.2 Functional Description
M-8870 operating functions include a band split filter that separates the high and low tones of the received pair, and a digital decoder that verifies both the frequency and duration of the received tones before passing the resulting 4-bit code to the output bus.
Filter
The low and high group tones are separated by applying the dual-tone signal to the inputs of two 6th order switched capacitor band pass filters with bandwidths that correspond to the bands enclosing the low and high group tones. The filter also incorporates notches at 350 and 440 Hz, providing excellent dial tone rejection. Each filter output is followed by a single-order switched capacitor section that smoothes the signals prior to limiting. Signal limiting is performed by high gain comparators provided with hysteresis to prevent detection of unwanted low-level signals and noise. The comparator outputs provide full-rail logic swings at the frequencies of the incoming tones.
Decoder
The M-8870 decoder uses a digital counting technique to determine the frequencies of the limited tones and to verify that they correspond to standard DTMF frequencies. A complex averaging algorithm is used to protect against tone simulation by extraneous signals (such as voice) while tolerating small frequency variations. The algorithm ensures an optimum combination of immunity to talkoff and tolerance to interfering signals (third tones) and noise. When the detector recognizes the simultaneous presence of two valid tones (known as signal condition), it raises the Early Steering flag (ESt). Any subsequent loss of signal condition will cause ESt to fall.
Steering Circuit
Before a decoded tone pair is registered, the receiver checks for a valid signal duration (referred to as character- recognition-condition). This check is performed by an external RC time constant driven by ESt. A logic high on ESt causes VC to rise as the capacitor discharges. Provided that signal condition is maintained (ESt remains high) for the validation period (tGTF), VC reaches the threshold (VTSt) of the steering logic to register the tone pair, thus latching its corresponding 4-bit code into the output latch. At this point, the GT output is activated and drives VC to VDD.
GT continues to drive high as long as ESt remains high. Finally, after a short delay to allow the output latch to settle, the delayed steering output flag (StD) goes high, signaling that a received tone pair has been registered. The contents of the output latch are made available on the 4-bit output bus by raising the threestate control input (OE) to a logic high. The steering circuit works in reverse to validate the interdigit pause between signals. Thus, as well as rejecting signals too short to be considered valid, the receiver will tolerate signal interruptions (dropouts) too short to be considered a valid pause. This capability, together with the ability to select the steering time constants externally, allows the designer to tailor performance to meet a wide variety of system requirements.
Figure 19 basic steering circuit
Figure 20 single ended input configuration
Input Configuration
The input arrangement of the M-8870 provides a differential input operational amplifier as well as a bias source (VREF) to bias the inputs at mid-rail. Provision is made for connection of a feedback resistor to the op-amp output (GS) for gain adjustment. In a single-ended configuration, the input pins are connected as shown in the Single - Ended Input with the op-amp connected for unity gain and VREF biasing the input at 1/2VDD. The Differential Input Configuration bellow permits gain adjustment with the feedback resistor R5.
3.1.3.3 DTMF Clock Circuit
The internal clock circuit is completed with the addition of a standard 3.579545 MHz television color burst crystal. The crystal can be connected to a single M-8870 as or to a series of M-8870s. As illustrated in the Common Crystal Connection below, a single crystal can be used to connect a series of M-8870s by coupling the oscillator output of each M-8870 through a 30pF capacitor to the oscillator input of the next M-8870.
Explanation of Symbols
VIN DTMF composite input signal.
ESt Early steering output. Indicates detection of valid tone frequencies.
St/GT Steering input/guard time output. Drives external RC timing
circuit.
Q1 - Q4 4-bit decoded tone output.
StD Delayed steering output. Indicates that valid frequencies have been
present/ absent for the required guardtime, thus constituting a valid
signal.
OE Output enable (input). A low level shifts Q1 - Q4 to its high
Impedance state.
tREC Maximum DTMF signal duration not detected as valid.
tREC Minimum DTMF signal duration required for valid recognition.
tID Minimum time between valid DTMF signals.
tDO Maximum allowable dropout during valid DTMF signal.
tDP Time to detect the presence of valid DTMF signals.
tDA Time to detect the absence of valid DTMF signals.
TGTP Guard time, tone present.
TGTA Guard time, tone absent.
3.1.4 REGULATED POWER SUPPLY
The power supplies are designed to convert high voltage AC mains electricity to a suitable low voltage supply for electronics circuits and other devices. A RPS (Regulated Power Supply) is the Power Supply with Rectification, Filtering and Regulation being done on the AC mains to get a Regulated power supply for Microcontroller and for the other devices being interfaced to it.
3.1.5 APR 9600 RE-Recording Voice IC
1 Single-chip Voice Recording & Playback Device60- Second Duration
3.1.5.1 Features:
¢ Single-chip, high-quality voice recording & playback solution
- No external ICs required
- Minimum external components
¢ Non-volatile Flash memory technology
- No battery backup required
¢ User-Selectable messaging options
- Random access of multiple fixed-duration messages
- Sequential access of multiple variable-duration messages
¢ User-friendly, easy-to-use operation
- Programming & development systems not required
- Level-activated recording & edge-activated play back switches
¢ Low power consumption
- Operating current: 25 mA typical
- Standby current: 1 uA typical
- Automatic power-down
¢ Chip Enable pin for simple message expansion
3.1.5.2 General Descriptions:
The APR9600 device offers true single-chip voice recording, non-volatile storage, and playback capability for 40 to 60 seconds. The device supports both random and sequential access of multiple messages. Sample rates are user- selectable, allowing designers to customize their design for unique quality and storage time needs. Integrated output amplifier, microphone amplifier, and AGC circuits greatly simplify system design. the device is ideal for use in portable voice recorders, toys, and many other consumer and industrial applications.
APLUS integrated achieves these high levels of storage capability by using its proprietary analog/multilevel storage technology implemented in an advanced Flash non-volatile memory process, where each memory cell can store 256 voltage levels. This technology enables the APR9600 device to reproduce voice signals in their natural form. It eliminates the need for encoding and compression, which often introduce distortion.
Figure 18 ps: the APR9600 DIP&SOP
3.1.5.3 Functional Description:
APR9600 block diagram is included in order to describe the device's internal architecture. At the left hand side of the diagram are the analog inputs. A differential microphone amplifier, including integrated AGC, is included on-chip for applications requiring use. The amplified microphone signals fed into the device by connecting the ANA_OUT pin to the ANA_IN pin through an external DC blocking capacitor. Recording can be fed directly into the ANA_IN pin through a DC blocking capacitor, however, the connection between ANA_IN andANA OUT is still required for playback. The next block encountered by the input signal is the internal anti-aliasing filter. The filter automatically adjusts its response According to the sampling frequency selected so Shannonâ„¢s Sampling Theorem is satisfied. After anti-aliasing filtering is accomplished the signal is ready to be clocked into the memory array. This storage is accomplished through a combination of the Sample and Hold circuit and the Analog Write/Read circuit. Either the Internal Oscillator or an external clock source clocks these circuits. When playback is desired the previously stored recording is retrieved from memory, low pass filtered, and amplified as shown on the right hand side of the diagram. The signal can be heard by connecting a speaker to the SP+ and SP- pins. Chip-wide management is accomplished through the device control block shown in the upper right hand corner. Message management is provided through the message control block represented in the lower center of the block diagram. More detail on actual device application can be found in the Sample Application section. More detail on sampling control can be found in the Sample Rate and Voice Quality section. More detail on Message management and device control can be found in the Message Management section.
Figure 21 APR9600 BLOCK DIAGRAM
3.1.6 DC Motor
DC motors are configured in many types and sizes, including brush less, servo, and gear motor types. A motor consists of a rotor and a permanent magnetic field stator. The magnetic field is maintained using either permanent magnets or electromagnetic windings. DC motors are most commonly used in variable speed and torque.
Motion and controls cover a wide range of components that in some way are used to generate and/or control motion. Areas within this category include bearings and bushings, clutches and brakes, controls and drives, drive components, encoders and resolves, Integrated motion control, limit switches, linear actuators, linear and rotary motion components, linear position sensing, motors (both AC and DC motors), orientation position sensing, pneumatics and pneumatic components, positioning stages, slides and guides, power transmission (mechanical), seals, slip rings, solenoids, springs.
Motors are the devices that provide the actual speed and torque in a drive system. This family includes AC motor types (single and multiphase motors, universal, servo motors, induction, synchronous, and gear motor) and DC motors (brush less, servo motor, and gear motor) as well as linear, stepper and air motors, and motor contactors and starters.
In any electric motor, operation is based on simple electromagnetism. A current-carrying conductor generates a magnetic field; when this is then placed in an external magnetic field, it will experience a force proportional to the current in the conductor, and to the strength of the external magnetic field. As you are well aware of from playing with magnets as a kid, opposite (North and South) polarities attract, while like polarities (North and North, South and South) repel. The internal configuration of a DC motor is designed to harness the magnetic interaction between a current-carrying conductor and an external magnetic field to generate rotational motion.
Let's start by looking at a simple 2-pole DC electric motor (here red represents a magnet or winding with a "North" polarization, while green represents a magnet or winding with a "South" polarization).
Figure 22 Block Diagram of the DC motor
3.1.7 RELAY
Figure 23 RELAY
Equivalent to Good Sky Part# RW-SH-112D
Details:
These SPDT relays covers switching capacity of 10A in spite of miniature size for PCB Mount.
Contact Rating
¢ 12A at 120VAC
¢ 10A at 120VAC
¢ 10A at 24VDC
Coil Resistance
400ohm 12VDC
Life expectancy
Mechanical 10,000,000 operations at no load
Electrical 100,000 at rated resistive load
Applications:
¢ Domestic Appliances
¢ Office Machines
¢ Audio Equipment
3.2 SOFTWARE COMPONENTS
3.2.1 ABOUT SOFTWARE
Software used is:
*Keil software for C programming
*Express PCB for lay out design
*Express SCH for schematic design
3.2.2 KEIL µVision3
What's New in µVision3
µVision3 adds many new features to the Editor like Text Templates, Quick Function Navigation, and Syntax Coloring with brace high lighting Configuration Wizard for dialog based startup and debugger setup. µVision3 is fully compatible to µVision2 and can be used in parallel with µVision2.
3.3.3 What is µVision3
µVision3 is an IDE (Integrated Development Environment) that helps you write, compile, and debug embedded programs. It encapsulates the following components:
¢ A project manager.
¢ A make facility.
¢ Tool configuration.
¢ Editor.
¢ A powerful debugger.
3.3.4 Express PCB
Express PCB is a Circuit Design Software and PCB manufacturing service. One can learn almost everything you need to know about Express PCB from the help topics included with the programs given.
Details:
Express PCB, Version 5.6.0
3.3.4 Express SCH
The Express SCH schematic design program is very easy to use. This software enables the user to draw the Schematics with drag and drop options.
A Quick Start Guide is provided by which the user can learn how to use it.
Details:
Express SCH, Version 5.6.0
3.3.5 EMBEDDED C:
The programming Language used here in this project is an Embedded C Language. This Embedded C Language is different from the generic C language in few things like
a) Data types
b) Access over the architecture addresses.
The Embedded C Programming Language forms the user friendly language with access over Port addresses, SFR Register addresses etc.
Embedded C Data types:
Table 7 EMBEDDED C DATA TYPE
Data Types Size in Bits Data Range/Usage
unsigned char 8-bit 0-255
signed char 8-bit -128 to +127
unsigned int 16-bit 0 to 65535
signed int 16-bit -32,768 to +32,767
sbit 1-bit SFR bit addressable only
bit 1-bit RAM bit addressable only
sfr 8-bit RAM addresses 80-FFH only
Signed char:
o Used to represent the “ or + values.
o As a result, we have only 7 bits for the magnitude of the signed number, giving us values from -128 to +127.
3.3 CIRCUIT DESCRIPTION:
This project is basically aimed to build a system in which the controlling of industrial appliances is done based on IVRS. This system consists of DTMF decoder, voice IC, micro controller, and appliances.
Whenever user wants to control the industrial appliances, he needs to call the mobile which is already interfaced with DTMF decoder and voice IC. Here user keeps the mobile in auto-answer mode, which automatically lifts the call and user is able to listen voice instructions also. Based on key selection the particular appliance is going to made ON/OFF.
DTMF decoder is used to decode the frequencies from the mobile and voice IC is used to store the voice instructions. Micro controller plays major role in directing the data to respective appliances.
Chapter 4
FINAL DESCRIPTION
4.1 CONCLUSION
The project Interactive Voice Response System (IVRS) has been successfully designed and tested. Integrating features of all the hardware components used have developed it. Presence of every module has been reasoned out and placed carefully thus contributing to the best working of the unit.
Secondly, using highly advanced ICâ„¢s and with the help of growing technology the project has been successfully implemented.
4.2 FUTURE ASPECTS
In this project, there is a voice processing unit in which we can record and playback the voice for a minimum duration of 60 seconds only. So we can replace this unit with more voice storage device so that we can utilize for a wide range of applications in industries, colleges etc. Just like controlling the devices in a industry and as well as marks announcement in colleges etc.
4.3 BIBLIOGRAPHY
4.3.1 NAME OF THE SITES
1. WWW.MITEL.DATABOOK.COM
2. WWW.ATMEL.DATABOOK.COM
3. WWW.FRANKLIN.COM
4. WWW.KEIL.COM
5. teltone.com
4.3.2 REFERENCES
1. 8051-MICROCONTROLLER AND EMBEDDED SYSTEM.
Mohd. Mazidi.
