Voice Recognition System and its Working Operation

The voice recognition system is the capacity of a device or program to receive and understand dictation, or to understand a spoken instruction. When this system is used with a computer, analog signal must be converted into digital using ADC. In a computer, a digital data base, syllables and vocabulary of words and syllables are required to decode the signal. The forms of the speech are stored on the hard drive and loaded into memory when the program is run. The stored forms are checked by the computer against the o/p of the analog to digital converter. All types of voice recognition systems don’t produce accurate output. Because, dogs barking, children’s screaming and loud external sounds can generate false i/p.

These types of voices can be recognized only by using the voice recognition system in a quiet room. There is also some problem with some words which produces similar sounds like here & hear. To overcome this problem this system requires faster processors and RAMs which are available in the personal computers. However, these systems are available in the market and also the industry leaders of the voice recognition systems are Dragon system and IBM.

Voice Recognition Security System

The main concept of this project is to design a voice recognition security system. This project is mainly used for security purpose to identify the voice password spoken from the authorized person and the system opens when the password is correct. This system will be controlled by PIC microcontroller which can be programmed with assembly language or C language.

Classification of Voice Recognition System

The voice recognition system is classified into four types such as Isolated VRS, Continuous VRS, Speaker Dependent VRS and Speaker Independent VRS.

• Isolated VRS requires a brief pass b/n the spoken words
• Continuous VRS doesn’t require a brief pass b/n the spoken words
• Speaker Dependent VRS identifies speech from only one speaker
• Speaker Independent VRS identifies anyone’s speech.

Hardware Design of Voice Recognition Security System

This Voice Recognition Security System project is designed with three main elements such as microphone circuit, microcontroller and LCD display The designing of this voice recognition security system project is very easy. The microphone circuit is connected to the analog to digital circuit of the PIC microcontroller. The digitalzed word passé through the digital filters. The owl process is done on the microcontroller, once the process is done, then the LCD display is connected to the microcontroller to display the spoken word matches the inbuilt password or not.

Microphone or Mike

A microphone, sometimes denoted to as a mic or mike, is a sensor or transducer which is used to convert the sound into an electrical signal. The applications of microphone mainly involve tape recorders, radios, broadcasting of TVs, telephones. In a capacitor microphone also known as condenser microphone, the diaphragm acts as one terminal of the capacitor, and the vibration changes in the distance between the two terminals. To extract an audio o/p from the transducer, there are two methods known as DC biased and HF or RF condenser microphones.

Microcontroller Unit

MCU is a computer on a chip and it has low power consumption, self-sufficiency, high integration. The microcontroller normally integrates extra elements like ROM for code storage, R/W memory for storing the data I/O interfaces and peripheral devices. This MCU consumes less power and generally it has the capability to sleep while waiting for another peripheral event like when a button is pressed to wake up them and to do something again.

Microcontrollers are often used in automatic controlled devices and products, such as remote controls, automobile engine control systems, power tools, office machines, toys and appliances. By reducing the cost, size, & power consumption compared to other I/O devices, microprocessor, memory, microcontrollers makes it inexpensive to control many processes electronically.

Single Board Computer-Atmega32

ATmega321644 is a small computer with Single-board based on the Atmel family, such as ATmega32 or Atmel ATmega644 AVR processor. This board was designed with a cooperation of Holger Bu, Ulrich Radig and Thomas Scherer with the first intent to control a coffee machine remotely through the internet.

This single board computer supports up to 2048 bytes of RAM. It includes a specially designed embedded OS. Though quite related to the ECB-ATmega321644 and the ECB-AT91, has individual features. It operates in the range of bare minimum energy consumption less than 100mA. It is still used as a web server for monitoring the web cam, web based remote control. But, small amount of power, the capacity of the web server is low and mainly the device is aimed for low intensity use.

LCD Display

A liquid crystal display (LCD) is a flat and thin display and it is made up of monochrome pixels arranged in front of a reflector. It is frequently used in an electronic devices, which are powered by a battery. Because it includes a small amount of power. The LCD display used in this project is alphanumeric type which displays alphabetical, symbolic characters and numerical from the standard ASCII character set. This type of display also displays low resolution graphics.

Software development

Multisim 2001

Multisim 2001 tool is used to design a system and it offers a huge amount of database, schematic entry, simulation, VHDL design, synthesis of FPGAICPLD, RF capabilities, Postprocessing etc. This tool provides a single and easy to use graphical interface for all designs and offers advanced functions, but you have to take designs from production. Because, the program integrates PCB layout, programmable logic, schematic capture and simulation.

• It supports all the circuit design process, includes design entering into the software tool being used
• Verifying the circuit behavior, this is done using simulation & analysis.
• Modifying the circuit design, if the circuit behavior does meet expectations.

For instance, if it is to be located on a printed circuit board, the further step is to use a PCB layout program (Electronics Workbench’s Ultiboard product). If it is to be located on a PLD (programmable logic device) or CPLD or FPGA the next step is to use a synthesis tool , that is available from Electronics Workbench.

This is all about voice recognition system and its working. We hope that you have got a better understanding of this concept. Furthermore, any queries regarding this topic or voice recognition modules, please give your feedback by commenting in the comment section below. Here is a question for you, what are the applications of voice recognition system.

Photo Credits:

• Voice Recognition Security System by zeendo
• Voice Recognition Module by imimg
• ATmega321644 by thinnkware
• Multisim 2001 by downza