Alt-BEAM Archive
Message #01214
To: Richard Caudle richard@cqc.com
From: CBC dmacq@interlog.com
Date: Tuesday, March 02, 1999 8:14 AM
Subject: Re: capaciflector
>Richard:
>
> Thanks again for all your thoughts. I'll go look for a few lm358s. I also
>thought they would be good for obstacle avoidance for a robot. They'd also
>be good for a long distance theremin if it's true they can detect from many
>feet away.
> Good idea about using the driver cricuit as the sensor plate.
> I plan to use my Basic stamp (1) to read it. As I say I haven't had much
>luck so far. I presume you use the pulsin command, but if you have any
>thoughts to the contrary let me know. I'm kind of shaky with this stuff..
>
>
>
>Cheers and thank you VERY much for your help.
>
>
>MACQ
>
>'ll At 03:57 PM 3/1/99 -0500, you wrote:
>>I tried using 741's at first, but they never seemed to work right. Try an
>>LM358 Dual Op Amp. That way you need only a single chip and four
resistors.
>>It's best to get a precision potentiometer to use in place of the 1M
>>resistors. I have been able to tune the sensor's frequency output up to
>>over 250Khz.
>>
>>I have thought it would be a good circuit to use as a motor controller.
The
>>frequency output goes up as the sensor approaches an object. My thought
was
>>that I could build in collision avoidance without using Nv's to do the
>>trick.
>>
>>It's also a good practice to use the actual driver circuit as the sensor
>>plate. That way you cut down on spurious detections.
>>
>>Richard Caudle
>>richard@cqc.com
>>rwcaudle@hpamonon.com
>>Frankendaddy (ICQ#20105579)
>>_________________________
>>
>>"Guardians of The Sacred Words: Nee, Ptang, and Neewhon."
>>
>>-----Original Message-----
>>From: CBC
>>To: Richard Caudle
>>Date: Sunday, February 28, 1999 9:55 PM
>>Subject: Re: capaciflector
>>
>>
>>>Thanks Richard.
>>>
>>>I'd already found that site but wondered if you had a different version.
It
>>>doesn't seem to work all that well for me (I'm using 741s) But the
>>>geometry clue is intriguing...
>>>
>>>thanks again.
>>>
>>>MAcQ
>>>
>>>
>>>
>>>The At 10:00 AM 2/28/99 -0500, you wrote:
>>>>Hello there,
>>>>
>>>>Try looking at http://cdr.stanford.edu/Touch/prox/cpcflctr.html
>>>>
>>>>I have had the best luck using the LM358. I have another version that
is
>>>>vastly superior, but my company will not allow me to release information
>>>>about it yet. The 'classic' capaciflector works well enough. Just keep
>>in
>>>>mind that the geometry of the sensor is critical to it's performance.
>>>>
>>>>Richard Caudle
>>>>richard@cqc.com
>>>>rwcaudle@hpamonon.com
>>>>Frankendaddy (ICQ#20105579)
>>>>_________________________
>>>>
>>>>"Guardians of The Sacred Words: Nee, Ptang, and Neewhon."
>>>>
>>>>
>>>>
>>>>
>>>
>>>Cheers,
>>>
>>>MACQ
>>>
>>>
>>>
>>>
>>
>>
>>
>
>Cheers,
>
>MACQ
>
>
>
>
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