hie guys. i am Reginald. i am doing a project at school and i am having troubles choosing a sensor to measure the speed of a vehicle and interface it with a microcontroller, a PIC family microcontroller

HC-SR04 Ultrasonic Distance Sensor is a popular and low cost solution for non-contact distance measurement function. It is able to measure distances from 2cm to 400cm with an accuracy of about 3mm. This module includes ultrasonic transmitter, ultrasonic receiver and its control circuit.

HC-SR04 module has 4 pins :

VCC – 5V, +ive of the power supply
TRIG – Trigger Pin
ECHO – Echo Pin
GND – -ive of the power supply
TRIG and ECHO pins can be used to interface this module with a microcontroller unit. These are TTL (0 – 5V) input output pins.