Arduino movement distance with only ultrasonic senzor

Question

Is it possible measure a robot car movement distance only with ultrasonic sensor ??

I working on robot car, in the picture you can see how i placed my ultrasonic sensors(red points) and my question is if i can get width value??

Answer 1

Yes it is possible. The low cost HC-SR04 sensor, can measure objects from 2cm to 4-5m.

The sensor will send some pulses and measure the time, until the pulses returns. So you can just measure the time (short pulse = near, long pulse = far).

There is just 1 problem with your car:
- it must reflect your pulses. If you don't have any wall or obstacles, you will always detect the maximal pulse with.

If you are inside a room, you can detect the movement. If you are outside or in a big room (more than 8x8m), this is not possible.