Alt-BEAM Archive
Message #08686
To: beam@sgiblab.sgi.com
From: Max Inggal tacoman101@yahoo.com
Date: Thu, 30 Dec 1999 09:16:40 -0800 (PST)
Subject: [alt-beam] Re: FLED Photovore
I'll see if I can draw the schem in Painter or
something so I can post it to the list. Plus I have a
FLED photovore twitching around in my RJP as we speak
so if you don't think it's possible guess again.
--- Bob Shannon wrote:
> Its not quite so simple Max.
>
> A 1381 has 3 leads, a FLED only two.
>
> Care to publish a schematic so we can see what you
> have?
>
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8687 Thu, 30 Dec 1999 09:28:01 -0800 (PST) [alt-beam] Re: Servo Control Circuit beam@sgiblab.sgi.com Tai Heng
I found this on a site. It may, or may not helpyou.
http://www.electronicsforu.com/circuit/nov99/novcir2.htm
--- SG wrote:
> does anyone out there know if there is a circuit
> available for turning a
> regular geared DC motor into a servo? Maybe an IC
> chip that does this?
> I'm wanting to control some of my motors (already in
> my possesion) with a
> servo controller, without having to go out and buy
> the little buggers.
>
> -Sparkeeeeeeee
>
>
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8688 Thu, 30 Dec 1999 09:49:47 -0800 [alt-beam] Re: 2n7000 and speakers "'beam@sgiblab.sgi.com'" Wilf Rigter Travis you asked for it:
>I've been wanting to make a D1 solarengine
>to trigger a bicore to flash alternating LED's.
>I'm perfectly capable of constructing the
>circuit, but one thing illudes me--how is it
> that the 2N7000 circuit senses the light level!?!
Simple: the voltage across the diode reverses turning on the 2N7000 when
light changes to dark.
Here is the circuit from Ian's
http://www.beam-online.com/Robots/Circuits/circuits.html
<<...>>
While enough light is available for the solar cell to charge the cap, the
2N7000 is automatically turned off because the negative voltage on the
mosfet gate which is the forward voltage of the 1N4001 diode ie -0.6V with
respect to the mosfet source. After the cap is charged up and when it gets
dark(er) , the solar cell output voltage, loaded by the potentiometer, drops
below the capacitor voltage. Without the series 1N4001 diode the charge on
the cap would discharge back through the solar cell. But with the diode
blocking that reverse discharge current, the voltage across the diode
reverses to a positive voltage on the mosfet gate with respect to the mosfet
source to turn on the 2N7000 and power up the load. The pot can be adjusted
to adjust the light level at which the 2N7000 turns on.
>what are the most commonly used
>(from DigiKey):
>Microphones,Speakers,2N7000 MOSFETS
Lots of choices available from Radio Shack, Active Components and others but
here are some economical (US$ prices approximate) examples from DigiKey:
Microphones-- electret (two terminal) P9970-ND $1.00
Speakers--piezo beeper P9924-ND $1.50
2N7000 MOSFETS-- 2N7000-ND $0.50 or 10x better IRLD120-ND $1.00
enjoy
wilf
> -----Original Message-----
> From: Travis D. [SMTP:beam_bot@yahoo.com]
> Sent: Wednesday, December 29, 1999 5:23 PM
> To: beam@sgiblab.sgi.com
> Subject: 2n7000 and speakers
>
> Hey all,
>
> I've been wanting to make a D1 solarengine to trigger
> a bicore to flash alternating LED's.
8689 Thu, 30 Dec 1999 09:53:33 -0800 (PST) [alt-beam] Re: FLED Photovore beam@sgiblab.sgi.com "Travis D." I've actually noticed this too w/ FLED's...it charges
but then as it begins flashing the voltage
fluctuates...
--- Jason Chang wrote:
> :P actually, i drove myself crazy thinking about
> this.. it seemed to be so,
> since the 1381 , afaik, is used as sort of an
> electronic switch set to
> close and open at predetermined levels. i've tried
> it with FLEDs... and
> believe me, the bot's behaviour is highly erratic...
> could this be due to
> the characteristics of the FLED?
>
> ----------
> > From: Phillip A. Ryals
> > To: beam@sgiblab.sgi.com
> > Subject: RE: FLED Photovore
> > Date: Thursday, December 30, 1999 11:01 PM
> >
> > >but one of the pins on the 1381 is ground, isn't
> it?
> >
> >
> > That's what I was wondering... Could it be just
> a matter of connecting
> the
> > FLED on the other two points?
> >
> > Hate to drive everyone nuts with attachments, but
> would it be like this?
> >
> >
>
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8690 Thu, 30 Dec 1999 09:57:55 -0800 (PST) [alt-beam] FLED Schem beam@sgiblab.sgi.com Max Inggal
--0-1804289383-946576675=:3216
content-disposition: inline
Ok since everyone is wondering how to make a FLED
photovore here's the Schem I used for mine. Sorry for
the pure crappiness of it but I just whipped it up to
show everyone. Also everyone was talking about how
the FLED vore acts funny. That because if you don't
cover the FLEDs the trigger time will always fluchuate
depending on how much light hits the FLED. Also the
FLEDs are affected by temp, but this only affects them
if 1 FLED is in 50 degrees and the other FLED is in
100 degrees. Very unlikely. Well anyway here yah go
the FLED schematic:
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--0-1804289383-946576675=:3216
Attachment: FLED.jpg
--0-1804289383-946576675=:3216--
8691 Thu, 30 Dec 1999 07:27:41 +0100 Re: interesting robot address Rob
> Lukas,
> I guess it uses up the battery in minutes to wind in the spring arm =
but
> the body does lend itself to a flexible solar panel, eh?
> Rob
>=20
> Lukas Garberg wrote:
>=20
> > That little cutie was cool!!!
> > I am now downloading the 11 mb movie.............
> > 33,6 modems SUCKS!!!
>=20
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