guidance for blind people

Hello, I would start a project for a guidance device for blind people. I would use a sfr range radar. The radar is able to detect an object at exactly 40 cm, for example? if so, what variable can I use to tell my program to make a sound when my radar detects an object 40 cm away?

tanks
em

It isn't a radar, it's a sonar.
Yes, it should be able to detect an object 40cm away.

what variable can I use to tell my program to make a sound when my radar detects an object 40 cm away?

That really depends upon what sound-generating hardware you have, and how it is connected.

I would use a sfr range radar.

What is the type of this radar?
link to datasheet?