Frank B. Scalzo writes:
> I am working on a project that needs to find the distance to objects.
> Currently I am using using a PIC16C84 as my controller. I'm using 40kHz
> transmit and recieve transducers from polaroid.
[snip]
> I detect ghost (false) signal returns. Any suggestions to improve my
> design?

This topic was discussed in some detail recently, with talk of schemes
for improving detection of the return pulse. Have a look at the
piclist archive which Andrew Warren just today gave the URL of and
which is

        http://www.428main.com/piclist/

Mal Goris
--
http://www.nfra.nl/~mgoris/