[PIC] blind spot detector in car

[gayathripv7]

Please help!
Hi, i'm quite new to pic microcontroller and i'm seeking some help. my project is on blind spot detection in car.The objective of this project is:
i.To alert the driver when changing the lane or make a turn
ii. To ensure the driver safety while overtaking or being overtake
iii. To prevent fatal accident involving blind spot region
Here i'm using pic 16f877a and ultrasonic sensor HCSR04. i thought of keeping 3 sensors on right side of the car. 1st sensor at extreme front,2nd at middle and 3rd at extreme back.when vehicle overtakes,the 3rd on goes high then 2nd then the 1st,in that case buzzer should beep and when vehicle comes opposite to the car, it cuts the 1st sensor then 2nd then 3rd , in that case buzzer should not beep..can anyone please help....
can anyone please right the source code for this project

https://obrazki.elektroda.pl/3358349200_1428729517.png



<a title="caaaaaaaaaaaar.png" href="http://obrazki.elektroda.pl/3358349200_1428729517.png"><img src="http://obrazki.elektroda.pl/3358349200_1428729517_thumb.jpg" alt="caaaaaaaaaaaar.png" /></a>

 

[betwixt]

I can't help but I would urge caution when using ultrasonics between object moving at high speed in turbulent air. Even doppler shift could stop it working but I would imagine the sound pressure waves would be severely distorted by the air flow. Consider a vehicle travelling at say 100Kph against an air stream of 20Kph, the chances are the sound reflection would be displaced enough that they never reach the sensor.

Brian.