Vehicle Accident Prevention Using eye Blink Sensor

Now a day’s accidents are increasing at a large pace, and various technologies are being introduced to reduce the accidents. In this project we provide means of accident prevention using eye blink wherein the vehicle is stopped immediately and intimated wherever needed.

In this project we have two sections. One is transmitter section which is located in the vehicle and another one is Receiver section located in remote place (Police station, near ones, etc). In the transmitter section the eye blink sensor is placed near the eye to sense the blink count and this information is transmitted in the form of pulses and is given to the Microcontroller. The Microcontroller uses this information to compare with the normal eye blink programmed in the chip and if any abnormal situation arises the vehicle is stopped with an alarm indication, this operation is enabled by means of the driver circuit connected to the vehicle motor and the signal is transmitted via RF-transmitter at the frequency of 433.92 MHz. In the Receiver side the transmitted signal is received and the signal is decoded and given to the Microcontroller, which uses this information for displaying the alert message in the LCD as programmed, simultaneously a buzzer alert is given.

LIST OF HARDWARE MODULES:

1.Power Supply for 8051 Microcontroller

This section describes how to generate +5V   DC power supply

The power supply section is the important one. It should deliver constant output regulated power supply for successful working of the project. A 0-12V/1 mA transformer is used for this purpose. The primary of this transformer is connected in to main supply through on/off switch& fuse for protecting from overload and short circuit protection. The secondary is connected to the diodes to convert 12V AC to 12V DC voltage. And filtered by the capacitors, which is further regulated to +5v, by using IC 7805

Microcontroller

A microcontroller (also microcontroller unit, MCU or µC) is a small computer on a single integrated circuit consisting of a relatively simple CPU combined with support functions such as a crystal oscillator, timers and etc. Microcontrollers are used in automatically controlled products and devices, such as automobile engine control systems, remote controls, office machines, appliances, power tools, and toys. The input and output device or connected to port pins of the controller. Typical input and output devices include switches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency devices, and sensors for data such as temperature, humidity, light level etc. The device, such as GSM, GPS and RFID are interfaced to the controller via serial communication i.e. TX and RX pins. 

2. ENCODER

The HT-12E IC encode 12-bits of information and serially transmits this data on receipt of a Transmit Enable and a LOW signal on pin-14 /TE.  Pin-17 the D_OUT pin of the HT-12E serially transmits whatever data is available on pins 10, 11, 12 and 13, or D0, D1, D2 and D3.

3. RF TRANSMITTER

The TWS-434 transmitter accepts both linear and digital inputs can operate from 1.5 to 12 Volts-DC, and makes building a miniature hand-held RF transmitter very easy. The P2_0, P2_1, P2_2 and P2_3 pin of controller is assumed as data transmit pins. The DATA_OUT pin of encoder is connected to the DATA_IN pin of RF Transmitter and then the RF Transmitter transmits the data to the receiver.

4. DECODER

The 212 series of decoders are capable of decoding information’s that consist of N bits of address and 12_N bits of data. Of this series, the HT12D is arranged to provide 8 address bits and 4 data bits, and HT12F is used to decode 12 bits of address information. The VT, or valid transmission pin of the HT-12D could signal the microcontroller to grab the 4-bits of data from the data output pins.

5.RF RECEIVER

The receiver also operates at 433.92MHz, and has a sensitivity of 3uV.  The TWS-434 receiver operates from 4.5 to 5.5 volts-DC, and has both linear and digital outputs. The P2_0, P2_1, P2_2 and P2_3 pin of controller is assumed as data transmit pins. The DATA_OUT pin of RF Transmitter is connected to the DATA_IN pin of DECODER and then the data is processed by the decoder.

4. RELAY

 A relay is an electrically operated switch. Electric current through the coil of the relay creates a magnetic field which attracts a    lever and changes the switch contacts.  The coil current can be on or off so relays have two switch positions and they are double-throw (changeover) switches. A simple electromagnetic relay, such as the one taken from a car in the first picture, is an adaptation of an electromagnet. It consists of a coil of wire surrounding a soft iron core, an iron yoke, which provides a low reluctance path for magnetic flux, a movable iron armature, and a set, or sets, of contacts. The armature is hinged to the yoke and mechanically linked to a moving contact or contacts. It is held in place by a spring so that when the relay is deenergized there is an air gap in the magnetic circuit. In this condition, one of the two sets of contacts in the relay pictured is closed, and the other set is open. The P0_0, P0_1, P0_2 and P0_3 pin of controller is assumed as data transmit pins to the relay through relay driver ULN 2003. ULN 2003 is just like a current driver.

Block Diagram

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POWER TRANSFORMER PROTECTION USING MICROCONTROLLER BASED RELAY

                            POWER TRANSFORMER PROTECTION

This Project is designed with Peripheral Interface Controller (PIC 16F877A). Utility companies have enormous amounts of money invested in transformers of all types, including distribution and power transformer. Operating, maintaining, and inspecting all power transformers are not an easy work. In order to reduce burden on maintenance of such transformers a new idea has been discovered.

This project is mainly used to protect the transformer from getting worn out due to electrical disturbances. The electrical parameters like current, voltage of the transformers are fed as base values, using a keypad to the Peripheral Interface Controller and the output signal is provided to operate a relay by comparing the base values with the operating electrical parameters. The application consists of a board of electronic components inclusive of a PIC 16F877A microcontroller with programmable logic. It has been designed to work with high accuracy. The electrical parameters of the power transformer such as voltage and current are fed to the Peripheral Interface Controller as base values. The voltage and current value during the operation of the power transformer is monitored and fed to the controller. These values are monitored using a LCD display. By comparing these values the Peripheral Interface Controller produces a trip signal which operates the relay and in turn the connectivity between main supply and the power transformer is cut off, thus protecting the power transformer from malfunctioning. In proposed method, monitoring and protecting the power transformer from over voltage and over current are performed automatically by using PIC microcontroller.

Components of the project:

  Rectifier, filter and Regulating circuit (Power circuits)

Voltage measuring circuit using Potential Transformer

  Current measuring circuit using Current Transformer

  Keypad and LCD display

  Driver circuit and a Relay

  PIC 16F877A microcontroller board

The protection system of transformer is inevitable due to the voltage fluctuation, frequent insulation failure, earth fault, over current etc. Thus the following automatic protection systems are incorporated.

1.      Buchholz devices:

A Buchholz relay, also called a gas relay or a sudden pressure relay, is a safety device mounted on some oil-filled power transformers and reactors, equipped with an external overhead oil reservoir called a conservator. The Buchholz Relay is used as a protective device sensitive to the effects of dielectric failure inside the equipment. It also provides protection against all kind of slowly developed faults such as insulation failure of winding, core heating and fall of oil level.

2.      Earth fault relays: 

An earth fault usually involves a partial breakdown of winding insulation to earth. The resulting leakage current is considerably less than the short circuit current. The earth fault may continue for a long time and creates damage before it ultimately develops into a short circuit and removed from the system. Usually provides protection against earth fault only.

3.      Over current relays:

An over current relay, also called as overload relay have high current setting and are arranged to operate against faults between phases. Usually provides protection against phase -to-phase faults and overloading faults.

4.      Differential system:

Differential system, also called as circulating-current system provides protection against short-circuits between turns of a winding and between windings that correspond to phase-to-phase or three phase type short-circuits. It provides protection against earth and phase faults.

 The complete protection of transformer usually requires the combination of these systems. Most of the transformers are usually connected to the supply system through series fuses instead of circuit breakers. In existing method the transformer does not have automatic protective relays for protecting the transformer.

Common Transformer faults

As compared with generators, in which many abnormal conditions may arise, power transformers may suffer only from:

1.      Open circuits

2.      Overheating

3.      Winding short-circuits

1 Open circuit Faults:

An open circuit in one phase of a 3-phase transformer may cause undesirable heating. In practice, relay protection is not provided against open circuits because this condition is relatively harmless. On the occurrence of such a fault, the transformer can be disconnected manually from the system.

2 Overheating Faults:

Overheating of the transformer is usually caused by sustained overloads or short circuits and very occasionally by the failure of the cooling system. The relay protection is also not provided against this contingency and thermal accessories are generally used to sound an alarm or control the banks of fans.

3 Winding Short-circuit Faults:

Winding short-circuits (also called internal faults) on the transformer arise from deterioration of winding insulation due to overheating or mechanical injury. When an internal fault occurs, the transformer must be disconnected quickly from the system because a prolonged arc in the transformer may cause oil fire. Therefore, relay protection is absolutely necessary for internal faults.

Conclusion

Transformers are static devices, totally enclosed and generally oil immersed. Therefore chances of faults occurring on them are very rare. However the consequences of even a rare fault may be very serious unless the transformer is quickly disconnected from the system. This necessitates to provide adequate automatic protection for transformers against possible faults. The major faults on transformers occur due to short circuits in the transformers or in their connections. The basic system used for protection against these faults is the differential relay scheme.

Protection of power transformer is a big challenge nowadays. By the help of microcontroller based relay, protection of transformer is performed very quickly and accurately. This system provides a better and safer protection than the other methods which are currently in use. The advantages of this system over the current methods in use are fast response, better isolation and accurate detection of the fault. This system overcomes the other drawbacks in the existing systems such as maintenance and response time.

Block Diagram

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