Tuesday, 29 January 2013

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.

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

A microcontroller (also microcontroller unit, MCU or ┬ÁC) 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. 

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.

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.

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.

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.

 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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