building a cheap sonar

[texane]

Hi,

I am interesting in building my own sonar for learning purposes. To do
so, I bought a transmitter / receiver pair, but I have some basic questions,
such as:

0) how do you distinguish the transmitter from the receiver, is there
any sign for it? One's back is black and the other has no color (silver). The
one whose back is black has a 'T', standing for transmitter?

1) How do you know which pin is to be grounded?

2) What is the generated voltage on the receiver side? Will I need an amplifier?

3) Is a 5v input voltage right for transmitter input? How long must I hold the current up?

I thank anyone who can answer some of these questions or point me to docs / links / books.

Thanks for helping.

[Razor Concepts]

What transmitter and receiver did you buy? We have no clue what you bought.

[airman00]

you probably bought Ultrasonic transceivers - meaning each one could be receiver or transmitter

[Soeren]

Hi,

you probably bought Ultrasonic transceivers - meaning each one could be receiver or transmitter

Unless it was an RX/TX pair!

Only the cheap US-devices are "generic". Better types has a thinner disc for the RX to increase sensitivity and a thicker disk for TX to increase power handling
 The generic types is a compromise and less powerfull, sensitive and has lower possible distance for same power (and/or diameter).

[geek1]

Maybe you included this in your original post and I just missed it, but why are you building a sonar rangefinder instead of buying one?

[HDL_CinC_Dragon]

Maybe you included this in your original post and I just missed it, but why are you building a sonar rangefinder instead of buying one?

First sentence lol

[geek1]

First sentence lol

Oh...Sorry lol

[texane]

Thanks for helping.

The transducers I bought looks like the ones in:
http://www.societyofrobots.com/images/sensors_sonar.jpg

I know there are both a transmitter and a receiver since the
vendor told me so, but I cannot find a way to differentitate
between them.

Is there a way to pragmatically differentiate / test them? For
instance, when I plug the non grounded pin of one of them
to an io port and raise the signal up, I hear a very acute sound,
does it mean this is the transmitter (using a pic1f4550)?

Anyway, if you have any doc related to this kind of project,
let me know

Thanks all of you for helping,