Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: texane on January 04, 2009, 05:27:26 PM

Title: building a cheap sonar
Post by: texane on January 04, 2009, 05:27:26 PM
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.
Title: Re: building a cheap sonar
Post by: Razor Concepts on January 04, 2009, 06:11:16 PM
What transmitter and receiver did you buy? We have no clue what you bought.
Title: Re: building a cheap sonar
Post by: airman00 on January 04, 2009, 06:14:13 PM
you probably bought Ultrasonic transceivers - meaning each one could be receiver or transmitter
Title: Re: building a cheap sonar
Post by: Soeren on January 04, 2009, 06:22:12 PM
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).
Title: Re: building a cheap sonar
Post by: geek1 on January 04, 2009, 07:05:53 PM
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?
Title: Re: building a cheap sonar
Post by: HDL_CinC_Dragon on January 04, 2009, 07:22:55 PM
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
Title: Re: building a cheap sonar
Post by: geek1 on January 04, 2009, 07:50:56 PM
Quote
First sentence lol



Oh...Sorry lol
Title: Re: building a cheap sonar
Post by: texane on January 05, 2009, 01:43:07 AM
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,