All of you know the importance of a black box in locating an aircraft when it met with an accident. The black box provides the knowledge of its location and from it we can deduce the reason behind the accident. Similar concept is being introduced for the ground vehicles. Now a day the rate of accident is increasing alarmingly. If this project gets implemented we will know the exact coordinates of the vehicle, reason behind the accident etc. The information from it can be used to save the passengers, help insurance company to know the reason, can help in developing more improvised safer vehicles and roads.

Black box provides the information about what was the exact situation when car met with an accident. It will record vehicle speed, temperature, break status, fuel status etc. and store it in EEPROM. Moreover the presence of collision sensor will help to notify about the accident though GSM to the number provided. The GPS coordinates will provide the location of the vehicle. The values being stored in the EEPROM will give a complete picture of the position of vehicle at the time of accident. Using I2C the information can be retrieved from the memory.

Block Diagram

Block Diagram

Block Diagram of Black Box Card Reader

Black box Card reader

Components Required

  1. Fuel Sensor
  2. Distance Sensor
  3. Ultrasonic Sensor
  4. Collision Sensor
  5. Hall Effect Sensor
  6. Temperature Sensor
  7. Switches
  8. PIC Microcontroller
  10. Buzzer
  11. Hooter
  12. RS232
  13. PC
  14. Keypad
  15. Power Source
  16. GSM module
  17. GPS modem



The sensors are connected to the analog pins of the PIC (peripheral interface controller) microcontroller. When the vehicle starts or the whole system powered “Black Box System” will be displayed indicating the system is ready.

The temperature sensor will check the temperature inside the engine. LM35 is generally used as temperature sensor. It has precision and produces linear output voltage corresponding to the temperature. It measures the temperature inside the engine. The formulae to calculate temperature is:

Temperature ( oC) = Vout * (100 oC/V)

To check whether the driver is wearing the seat belt or not a switch is provided. Logic high or in closed position indicates driver is wearing for this IR jumper is used. The fuel level of the vehicle is analyzed using the fuel sensor. It is placed on the float valve of the fuel tank. The working of the fuel sensor is similar to that of a potentiometer as level of fuel decreases the resistance value increase. The distance sensor or proximity sensor is used to know the distance of the front part of the vehicle from the obstacle. IR rays are used. Infrared transmitted from the transducer get reflected back from the obstacle the time lapse will give the distance. The purpose of the ultrasonic sensor is to detect any obstacles present in the route. The ultrasonic waves are transmitted from the transmitter which upon hitting any object is reflected back and received by the transducer. The time duration between the transmitted and received will give the distance of the object. If vehicle reaches certain distance quite near to the obstacle an alarm will be generated either to alert the driver using buzzer or hooter.

Collision sensor, whenever a sudden negative acceleration is experienced it will close the crash switch and a signal is sent to the microcontroller. GSM (Global System for Mobile) module connected serially to the microcontroller will send a warning message to the emergency responder. The warning message will have the details about the accident and its location. GSM module is analogues to a normal phone, is a mobile communication modem used for wireless communication of cellular data. GSM requires a SIM card of a subscribed network operator. It uses TDMA technique for communicating data with its client. GPS or Global Positioning System provides the desired coordinates. At an altitude of 20000 km a network of 30 satellites are orbiting the earth. The GPS module will intercept the nearby satellite’s signal transmitting the current position and time. Depending upon the time lapse of receiving the message GPS receiver will calculate the how far the satellite is located thus giving the details about the current location.Magnet connected to the wheel upon each rotation comes closer to the Hall Effect Sensor blinking the LED connected to it. Depending upon the rotation of the magnet the vehicle speed can be calculated.

All the outputs from the sensors are given as input to the microcontroller. LCD connected to the microcontroller through port will display the values. Simultaneously these values will be stored in the EEPROM of the PIC. In case of accident these value will be retrieved from the PIC using I2C protocol to a PC using RS232.  

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