AW: AW: [basicstamps] sound detection
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Hi Mike,
that sounds very weird indeed, I would love to learn more about how you did
it. Is there more Information you could give me? I am not very good at
electronics, I basically understand you need a IR-LED, an IR-LDR, mybe an
op-amp and yes well, but what to do then?
How did you detect speet and direction? Did you use more than one pair?
Thanx for your help,
uli
Urspr
that sounds very weird indeed, I would love to learn more about how you did
it. Is there more Information you could give me? I am not very good at
electronics, I basically understand you need a IR-LED, an IR-LDR, mybe an
op-amp and yes well, but what to do then?
How did you detect speet and direction? Did you use more than one pair?
Thanx for your help,
uli
Urspr
Comments
I'll try to recover the old schematics. Contact me at my email address and
I'll send you a .pdf of the scanned schematic (it was 20 years ago and we
didn't have schematic software, then).
Basically, you are looking at the strength of a reflected signal. The
further away, the weaker the signal. Use an opamp (actually, I used a
Norton current amplifier, LM3900) to get a voltage swing in the range of
movement you are trying to detect. As I indicated, this requires tuning for
gain and offset. The signal should be centered around Vcc/2. Feed this
signal into an opamp differentiator to detect changes in position and
direction or just read the first stage directly and process it with the
stamp. We needed to use window comparators and AGC circuits, but I think I
would have only needed a single amp per input if I had it connected to an
A/D converter going into a Stamp.
Mike
At 09:45 AM 8/3/2001 +0200, you wrote:
>To: <basicstamps@yahoogroups.com>
>Subject: AW: AW: [noparse][[/noparse]basicstamps] sound detection
>
>Hi Mike,
>
>that sounds very weird indeed, I would love to learn more about how you did
>it. Is there more Information you could give me? I am not very good at
>electronics, I basically understand you need a IR-LED, an IR-LDR, mybe an
>op-amp and yes well, but what to do then?
>
>How did you detect speet and direction? Did you use more than one pair?
>
>Thanx for your help,
>uli
_________________________________
Mike Walsh
walsh@c...
California Institute of Technology
Biology Electronics Shop
MS 216-76
Pasadena, CA 91125
626-395-6825 , FAX 626-584-1654
237 Beckman Behavioral Biology Bldg.
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