Friday, 13 December 2013

Multipoint wireless data acquition system for vehicles-- Circuit Description --3


·         Flex sensor is an unique and sensitive component of car black box which changes resistance on bending. It changes its resistance when the sensor is press due to force and this sensor will embedded in car paint. And this sensor is connected to controller through ADC.

·         In this system LM35 temperature sensor is use to record temperature of vehicle i.e. cabin temperature and engine temperature and it is also connected to controller through ADC. And its output voltage is linearly proportional to Celsius.

·         The 3 axis sensor i.e. Accelerometer which is use to sense tilting of car or vehicle. It senses the current position of that system by taking its X-axis, Y-axis and Z-axis coordinates. This sensor connected to ADC which will connect the sensor to microcontroller.

·         The values which are sensed by the all parameters are displayed on LCD. And for that 16 x 2 alphanumeric LCD is use. The LCD can be mounted on dash board of car which will be more convenient for driver of the car.   

·           All these above sensors are at same priority level when this sensor goes above fix threshold microcontroller starts operating means it sends message via GSM transmitter.

·                                   Microcontroller Needs +5V DC for its operation so 230V AC is stepped down to 9V AC, then rectified using four 1N4007 diodes (connected in full wave bridge rectifier configuration). Then this DC as it is pulsating need to be smoothened, so a large value electrolytic capacitor is used for filtering. LM7805 (+5V voltage regulator) is used to provide constant +5V DC even if we have voltage fluctuation in 230V AC

·         This system should be mounted in one  box which should be tough and compact as possible as for the protection of all above sensors and it should be easily fixed in car.

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