Advise me..

Amst

Thank you Mr.Mike Green for replay and valuable viewpoint.
I can see that, as you said it's not at all practical but however if the repeatedly measure of the distance well done (apart from doppler effect which requires more sophisticated sensor or circuitry) , and if there is an audio system which interprets that measurement into spoken messages, there will be a simple prototype of indoor navigation system, which maybe useful for blind.
this is my opinion, what's yours?

Mike Green

I don't think it's practical, particularly with spoken messages because they take too long to carry meaningful information and people need to be able to move relatively quickly. One thing that you could experiment with that's available commercially uses a tone to represent distance. The device has been built into a glasses frame to use head movement for scanning and into the handle of a cane or wand so it can be scanned about with hand movement. It's really better to build it out of custom circuitry rather than something like a PING))) and a Stamp because the custom circuitry would have better performance, but you could experiment with the PING/Stamp.

My graduate school advisor was blind and had tried some of the early ultrasound devices. He very much preferred a seeing eye dog.