This document describes an automatic speed controlled car system that uses ultrasonic sensors to detect speed breakers and large obstacles. The system reduces the car's speed as it approaches a speed breaker or stops the car if a large obstacle is detected to avoid damage. It uses an ATMEGA32A microcontroller and L293D motor driver along with ultrasonic sensors to control the car's speed based on distance measurements from the sensors. The system provides safety benefits and could enable autonomous driving applications in the future.

1. AUTOMATIC SPEED CONTROLLED CAR
AUTOMATION FOR SAFETY

2. Submitted to
Md. Hasibul Alam
Lecturer, Department of EEE, BUET
Submitted by
0906166, 0906167, 0906168, 0906169,
0906170, 0906171, 0906172, 0806027

3. OBJECTIVE:
• To design a car which will detect speed breakers and large
obstacles and control its speed accordingly to avoid
damages.

4. COMPONENTS:
• 2 Ultrasonic Sensors (HC- SR04)
• 1 ATMEGA32A
• 1 L293D Motor Driver
• Switches
• Resistors

5. COMPONENTS:
HC- SR04
• 2 sensors are used
• Includes ultrasonic transmitter, receiver and control circuit
• Upper one for large obstacles
• Lower one for speed breakers

6. COMPONENTS:
HC- SR04
Wiring connections
• 5V VCC
• Trigger Pulse Input
• Echo Pulse Output
• Ground

7. COMPONENTS:
HC- SR04
The basic principle of work of HC - SR04 :
• Using IO trigger for at least 10us high level signal,
• The Module automatically sends eight 40 kHz and detect whether there is a pulse
signal back.
• IF the signal back, through high level , time of high output IO duration is the time
from sending ultrasonic to returning. Test distance (in meters)= (high level time ×
velocity of sound (340M/S) /2
•Distance in inches = Time / 148

8. OPERATION:
Speed Breakers:
• If a car running at V m/s detects a speed breaker 2 feets away,
it reduces its speed to V/2 m/s
• When the distance is 1 feet, its speed reduces to V/4 m/s

9. OPERATION:
Speed Breakers:
• After crossing, the speed again increases to V m/s

10. OPERATION:
Large Obstacles:
• If a large obstacle is detected, the car stops at 6 inches distance

11. CIRCUIT DIAGRAM:
Upper
Sensor
Lower
Sensor

12. LIMITAIONS AND SAFETY:
• L293D is heat sensitive, so operation can be hampered in case
of large power drop
• Heat sink should be used in whole system

13. ADVANTAGES:
• Security from damages
• Attractive for Electric Propulsion Motors
• Effective in highly populated areas
• Applicable for carrying goods in hospitals, industries, spaceships
etc.
• Important feature for vehicles used for collecting informations
in areas men cannot reach

14. FUTURE APPLICATIONS:
• Addition of wi-fi device to communicate with other cars around
to avoid collisions
• Addition of direction change systems

15. THANK YOU