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Randy Stadham
01-23-2006, 12:40 PM
Hi,

Is it possable to output 24Khz from a stamp I?
I need to drive a ultrasonic transmiter.
If not does anyone have a circuit·to make this possable?

Cheers,

Randy
·

Chris Savage
01-23-2006, 01:32 PM
Randy,

·· Aren't the ultrasonic transducers run at 40 kHz?· 24 kHz would be FREQOUT pin, duration, 24000


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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

Bruce Bates
01-23-2006, 02:02 PM
Randy -

Take a look at the FREQOUT command.

Regards,

Bruce Bates

Randy Stadham
01-23-2006, 06:33 PM
Bruce and Chris,

There is no freqout for a BS 1 as far as I know

Yes most ultrasonic tranducers work at 40 kHz but this one wants 24kHz to drive the MAX489.
See site:
http://frontrangerobotics.org/UltraSonic/

Cheers,

Randy

Bruce Bates
01-23-2006, 07:52 PM
Randy-

Please take a look at the attached PDF, specifically to Applications Note 12, which shows an entire Sonar Ranging Project, using a BS-1 and a Polaroid Ultrasonic Transducer. These are the original Parallax BS-1 Applications Notes, which for my money are still quite valid today as examples, although they are now a discontinued document. Some of us refuse to delete anything that Parallax once published :-)

You'll just have to adjust for the differing transmission frequency, but the basic theory should be fine. My apologies for not noticing originally that you were using a Stamp BS-1.

Regards,

Bruce Bates

Randy Stadham
01-23-2006, 10:32 PM
Hi Bruce,

Thanks for the note. Never hurts to look at what was done in the past. I too never throw anthing away you never know when you might need it.

I built this circuit a few months ago but never got it to work quite well. I do not have an o'scope which in this canse is almost a requirement. I never got the thing fine tuned enough even though I have a kHz measurement on my multi meter. But That never seemed to help. So I gave up and went and found another circuit.
I know I should buy a ping but I live too far from you guys. So I started to make one for myself. I am still working on it.

Thanks for the help.

Randy

Chris Savage
01-23-2006, 11:02 PM
Sorry Randy, didn't notice the I in your message.

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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)