In Reply to: Re: ultro sonics distance detector ! posted by Brian Snell on 01/31/02 at 1:27 PM:
Check out this site: http://www.polaroid-oem.com/ultrason.htm. They have a variety of pre-built modules, as well as individual components (including a couple of ASIC's, and the proper transformers). You can easily build a digital time measurement interface on top of their modules to display distance in digital forms.
If you plan on going it alone (without the ASIC's) you will need to be able to design a time proportional gain circuit as well as an echo suppressor (just a suitable time delay). Using a DAC controlled VCA together with a microcontroller is one approach to the time proportional gain control.