Driving is a compulsory activity for most of the people. The number of vehicles is increasing day by day. IN the same ratio the number of accidents are also increasing finally resulting in worst damage, serious injury and dead. These accidents are mostly caused by delay of the driver to hit the brake.
Automatic braking is a technology for automobiles to sense an imminent collision with another vehicle, person or obstacle; or a danger such as a high speed approach to a stop sign and to respond with the braking system by either recharging the brakes or by applying the brakes to slow the vehicle without any driver input. Sensors to detect other vehicles or obstacles can include radar, video, infrared, ultrasonic or other technologies. GPS sensors can detect fixed dangers such as approaching stop signs through a location database.
Using such systems to prevent crashes is problematic, so practical systems more often seek only to reduce crash speed in some situations.
Initially, this system warns the driver and prepares the brakes, then, if the driver does not brake while the impact is imminent brakes are activated automatically. It also employs a camera to detect vehicles in front of the car. A major advantage of the camera is the ability to detect stationary vehicles and warning the driver. "Statistics show that 50% of all collisions involving a vehicle or a stationary object, which means that Collision Warning with Auto Brake covers twice as many situations as the current system, "said Jonas Tisell, Project Manager for anti-collision systems at Volvo Cars.
This project is designed with microcontroller, Ultrasonic Transmitter, Receiver, Signal conditioning unit, Analog to Digital converter, Driver Circuit and Mechanical arrangement.
The oscillator circuit generate 40KHZ frequency signal. It is transmitted through ultrasonic transmitter. The ultrasonic receiver is used to receive the reflected wave due to in front of the vehicle. Then the reflected wave is given to signal conditioning unit in which the incoming wave is amplified and converted into square pulse. Then the square pulse is given to ADC. Depends upon distance the reflected wave strength is varied.
ADC is nothing but analog to digital converter, which converts the input analog signal into corresponding and digital signal. This digital signal is given to microcontroller.
The microcontroller may Atmel or PIC both are flash type reprogrammable microcontroller in which we have already programmed. So it received the signal from ADC displayed on the LCD display. This is equal to distance between the vehivle and front side object. The object may vehicle, trees or road barriers. Nearest dangerous distance value is already stored in the microcontroller. When measured distance is reached this value, microcontroller automatically activates the relay driver circuit. The relay output is directly connected to mechanical arrangement. Through this mechanical arrangement braking is provided and vehicle is stopped in order to avoid the accident
The main target of this project is car can automatically brake due to obstacles when the sensor senses it from its received signal.