Dual Tone Multiple Frequency

In telecommunication, a connection is created between two handsets – a caller and the cal lee. Earlier, rotary types dial were used, which are now replaced by the push button keys. Thus, the concept of DTMF comes into lime light. DTMF also known as Touch Tone, is a signaling system which is used to identify the pressed push button in a DTMF keypad. Multi-frequency signaling is a group of signalling methods that uses a mixture of two pure tone (pure sine wave) sounds. As the name suggests dual tone i.e., it generates a sinusoidal tone which is a mixture of the row and column frequencies. The row frequencies are low group frequencies. The column frequencies belong to high group frequencies. This prevents misinterpretation of the harmonics. The DTMF system comprises of a DTMF decoder and a DTMF keypad.

The applicative measures aim in designing and implementing cell phone operated systems using DTMF technology.Many communication application can be build for example, a computerize call receiving/diverting phone network system, remote control system for home/office electrical appliances, motors, voting machines, etc.

RS-232 Communication

RS-232 stands for Recommend Standard number 232. It is used for interfacing between the peripheral devices. Information being transferred between data processing equipment and peripherals is in the form of digital data which is transmitted in either a serial or parallel mode. Parallel communications are used mainly for connections between test instruments or computers and printers, while serial is often used between computers and other peripherals.

The applicative measures in implementing a PC operated system with Multiple Functionalities using RS-232 Protocol. Certain projects include optimisation of home appliance, control of wheel chair, land rovers etc.

IR Communication

IR data transmission is also employed in short-range communication among computer peripherals and personal digital assistants. These devices usually conform to standards published by IrDA, the Infrared Data Association. Remote controls and IrDA devices use infrared light-emitting diodes (LEDs) to emit infrared radiation which is focused by a plastic lens into a narrow beam. The beam is modulated, i.e. switched on and off, to encode the data. It responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light.

Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for remote controls to command appliances. Infrared remote control protocols like RC-5, SIRC, are used to communicate with infrared. The applicative measures aim in designing a Remote Controlled System Implementing IR Communication. Some of them include a New Generation Digital Notice Board Display System, programmable clocks etc.

GPS and GSM Communication

GSM or Global System for Mobile Communications, one of the leading digital cellular systems. GSM uses narrowband TDMA, which allows eight simultaneous calls on the same radio frequency. A GSM modem is a wireless modem that works with a GSM wireless network. A wireless modem behaves like a dial-up modem. The main difference between them is that a dial-up modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves. Like a GSM mobile phone, a GSM modem requires a SIM card from a wireless carrier in order to operate.

The various examples include Vehicle Theft Detection Mechanism, Electronic Voting Machine, home security system etc. The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S.A. GPS works in any weather conditions, anywhere in the world, 24x7. GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is.

This technology is implemented in various application such as School Kid Tracking System, Anti Collision Railway System, and Real Time Location Monitoring System etc.

Bluetooth Communication

Bluetooth is a specification for a small form-factor, low-cost, short-range radio solution for providing links between mobile computers, mobile phones, and other portable and hand-held devices, and for providing connectivity to the internet. It is based on a radio link that provides fast and reliable transmission of both voice and data. It can carry up to three high-quality voice channels simultaneously at speeds to 1 M bit/sec, even in noisy environments. Like USB, the specification incorporates both rules for implementing the interface and rules for designing compatible peripherals for the network.

Bluetooth allows users to connect to a wide range of devices at one time without cables, and potentially without actively initiating the connection. One concern when using such a system is privacy. As Bluetooth operates in the globally available 2.4 GHz frequency, it is conceivable that an unintended recipient could intercept a signal. To combat this, all Bluetooth devices are keyed for their own networks. The transmissions use a sophisticated encoding specification that not only guards against interference, it also ensures that only devices specifically programmed to receive a broadcast will be able to decode it.

Radio Frequency Identification(RFID)

Short for Radio Frequency Identification is a generic term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object or person wirelessly, using radio waves. It's grouped under the broad category of automatic identification technologies. The purpose of an RFID system is to enable data to be transmitted by a portable device, called a tag, which is read by an RFID reader and processed according to the needs of a particular application. The data transmitted by the tag may provide identification or location information, or specifics about the product tagged, such as price, color, date of purchase, etc. RFID technology has been used by thousands of companies for a decade or more. . RFID quickly gained attention because of its ability to track moving objects.

Some of its application using RFID are Metro Train Ticket System, Railway Platform to Display Position of Coach, Animal Identification Device for Dairy Farms, and Parts Tracking System for Manufacturers etc.

Biometric Finger Print Sensor

A biometric sensor can be termed as a product of advanced technology. It is an essential component of a biometric system which uses physical traits like fingerprints, retina, iris patterns, etc. to identify, verify and authenticate the identity of the user. Basically, a biometric sensor can be termed as a security system device that integrates unique physical traits and digital technology for recognition with high accuracy.

Conversion of analog into digital signals is one of the distinctive features of a biometric sensor. The biometric data fed as input are converted into the digital form for the database processing.
A biometric sensor is a built-in feature of swipe cards which may be used for employee identification, time attendance, access cards, credit card transactions, etc. They are used in e-commerce to authenticate the transactions and prevent online frauds to a vast extent. For ex- office attendance system, Electronic Door Opening and Closing system, Electronic lift operating system etc.

Touch Screen Sensor

A touch screen is a computer display screen that is also an input device. The screens are sensitive to pressure; a user interacts with the computer by touching pictures or words on the screen.
There are three types of touch screen technology Resistive (resistive layer that causes a change in the electrical current which is registered as a touch event and sent to the controller for processing), Surface wave (Surface wave technology uses ultrasonic waves that pass over the touch screen panel) and Capacitive (A capacitive touch screen panel is coated with a material that stores electrical charges).

The various applications of touch screen are prototyped as intensity control home appliance, surveillance robots etc.

Accelerometer Sensor

An accelerometer measures acceleration (change in speed) of anything that it's mounted on. Inside an Accelerometer MEMS device are tiny micro-structures that bend due to momentum and gravity. When it experiences any form of acceleration, these tiny structures bend by an equivalent amount which can be electrically detected. Today, accelerometers are easily and cheaply available, making it a very viable sensor for robotics hobbyists.

Accelerometers are very important in the sensor world because they can sense such a wide range of motion. They're used in cameras, to control image stabilization functions. They're used in gaming controls to generate tilt data. They're used in automobiles, to control airbag release when there's a sudden stop. There are countless other applications for them. The various applicative mechanism that Facilitate a Hand Gesture Control System are low power, motion- and tilt-sensing applications to control wheel chair, appliance etc.

Temp., Humidity, Heart Beat & Gas Sensors

A sensor, as the name suggests, is used to sense any type of disturbances e.g. sensors are sound sensor, temperature sensor, photo detector, PIR sensor etc. A sensor can give analog as well as digital value.A sensor (also called detector) is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. A sensor is a device which receives and responds to a signal.

A sensor's sensitivity indicates how much the sensor's output changes when the measured quantity changes. Sensors that measure very small changes must have very high sensitivities. Sensors also have an impact on what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Some examples can be noted as Alcohol Breath Analyzer, Temperature Analyzing System For Industrial Control, Multichannel Temperature Monitoring System etc.

IR & Ultrasonic Sensors

There are two types of IR sensors. One with built in circuits which provide a binary output, and there are those which provide an analog output or a multiple bit output. The sensors with a binary output are only good for detecting the proximity of an obstacle, and not the range i.e., the sensor can only tell you when an obstacle is within a certain distance. This is fine for most robots which only need to know when an obstacle is right in front of it. The other IR sensors, which are ranging sensors, output the actual distance of an obstacle from the sensor. This output can either be analog or a digital byte.

An ultrasonic sensor transmits ultrasonic waves into the air and detects reflected waves from an object. There are many applications for ultrasonic sensors, such as in intrusion alarm systems, automatic door openers and backup sensors for automobiles. Accompanied by the rapid development of information processing technology, new fields of application, such as factory automation equipment and car electronics, are increasing and should continue to do so.

Keypad

A keypad is a set of buttons arranged in a block or "pad" which usually bear digits, symbols and usually a complete set of alphabetical letters. If it mostly contains numbers then it can also be called a numeric keypad. Keypads are found on many alphanumeric keyboards and on other devices such as calculators, push-button telephones, combination locks, and digital door locks, which require mainly numeric input.

Keypads are generally employed in designing variety of projects like wheel chair control for orthopedically handicapped persons, land rover, appliance control etc.

Robotics

Robotics is the branch of technology that deals with the design, construction, operation and application of robots and computer systems for their control, sensory feedback, and information processing. A robot is a mechanical device that can perform tasks automatically. A robot is usually an electro-mechanical machine that is guided by a program or circuitry. Robots can be autonomous, semi-autonomous or can be remotely controlled.

Robots have replaced humans in the assistance of performing those repetitive and dangerous tasks which humans prefer not to do, or are unable to do due to size limitations, or even those such as in outer space or at the bottom of the sea where humans could not survive the extreme environments. The word robot can refer to both physical robots and virtual software agents, but the latter are usually referred to as bots. The designing and implementation of these concepts can be utilized in various applicative measures such as line follower, obstacle detector, edge detector etc.

RF Communication

Radio frequency (RF) is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals. Although radio frequency is a rate of oscillation, the term "radio frequency" or its acronym "RF" are also used as a synonym for radio – i.e. to describe the use of wireless communication, as opposed to communication via an electrical connector. In many situations a communication link between to devices becomes essential. This communication can be wired or wireless. If two devices are close to each other (like a MCU and a Memory) a wired link is preferred. However in many situations two devices are reasonably far apart. In that case a wireless link is preferred.

A RF Module is a small circuit pre built and tested. They come in Pair. One is RX or the receiver and other is a TX or Transmitter. Various applicative measures includes wireless home automation, land rover, digital notice board etc.

ZigBee Communication

ZigBee is the name for a short-range, low-power, low-cost, and low-data-rate wireless multi-hop networking technology standard. A ZigBee network consists of three types of logical devices viz. coordinator (Full Function Device, FFD), router and an end device (Reduced Function Device, RFD). Bluetooth and Wi-Fi should not be confused with ZigBee. Both Bluetooth and Wi-Fi have been developed for communication of large amount of data with complex structure like the media files, software etc. ZigBee on the other hand has been developed looking into the needs of communication of data with simple structure like the data from the sensors.

Why is it called ZigBee? It has been suggested that the name evokes the haphazard paths that bees follow as they harvest pollen, similar to the way packets would move through a mesh network. ZigBee, a specification for communication in a wireless personal area network (WPAN), has been called the “Internet of things.” Theoretically, your ZigBee-enabled coffee maker can communicate with your ZigBee-enabled toaster. The benefits of this technology go far beyond the novelty of kitchen appliances coordinating your breakfast.