Figure 2. Pulsed time-of-flight (TOF) measurement principle
We can regulate an autonomous vehicle’s braking system with ultrasonic
sensors to avoid accidents. Ultrasonic sensors can help autonomous
vehicles brake when they encounter obstacles. It goes like this:
Ultrasonic sensors face outward on the car’s front and back. Sensors
emit high-frequency sound waves and listen for echoes from nearby
objects. Sound waves’ travel time and return time define a sensor’s
distance from an object. The car’s autonomous driving system can brake
to slow or stop if an obstruction is within a certain range.
We try to prevent tragic accidents with supersonic. Our major goal is to
compute car-obstacle distances. See figure 3. Used HC-SR04 modules have
a 50-cm range. The sensor has an ultrasonic transmitter, receiver, and
management circuit. It has four pins: 5v VCC, input trigger pulse,
output feedback pulse, and ground. Ultrasonic sensor electrical
parameters: It operates at 5 V DC and 40 kHz. It requests the 10us TTL
pulse indication. Simply said, ultrasonic sensors use piezoelectricity.
After a 10 us rapid pulse, the module sends an audio beam of eight
ultrasonic cycles at 40 kHz. The receiver and microcontroller will
analyse the reflected wave (echo) after an impediment is detected. The
microcontroller will warn the driver if the distance exceeds the limit.
The period is the next trigger pulse transmitted once the received echo
is minimised. No less than 50 milliseconds for HC-SR04 cycle time.
[11].