Alt-BEAM Archive
Message #07863
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Sat, 20 Nov 1999 13:51:21 -0800
Subject: [alt-beam] Re: Cholroplast thingy
oops, here is the attachment
<>
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411
> -----Original Message-----
> From: Wilf Rigter [SMTP:Wilf.Rigter@powertech.bc.ca]
> Sent: Saturday, November 20, 1999 12:54 PM
> To: 'beam@sgiblab.sgi.com'
> Subject: RE: Cholroplast thingy
>
> Hey Craig,
>
> Yep, you have to use low leakage fet input opamps, especially if you use
> LEDs for photocells together with small low leakage caps. I would change
> the
> circuit slightly as shown in the attached to improve efficiency (kind of
> important with solar engines). With 5V(min) you can easily drive the
> mosfet
> gates. Not yet tested but uses fewer components, lower forward voltage.
> Note
> the 0.001 caps are used with the clear LED type (low sensitivity)
> photodiodes for filtering and snappy positive feedback. Exact cap values
> to
> be determined empirically.
>
> regards
>
> Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> tel: (604)590-7493
> fax: (604)590-3411
>
> > -----Original Message-----
> > From: Maynard [SMTP:cybug@home.net]
> > Sent: Saturday, November 20, 1999 9:53 AM
> > To: beam@sgiblab.sgi.com
> > Subject: Re: Cholroplast thingy
> >
> > Hi Richard / Wilf:
> >
> > Since the CSE is good for maintaining a useful minimum voltage ( 5V or
> so
> > )
> > I'd suggest you use a pair of good low current op-amps to monitor the
> > voltage level of the photodiodes and drive your Darlingtons / h-bridge.
> > That's what I did in the Sunflower and Solarfly, and it works quite
> well!
> > The high impedance inputs also cuts the leakage current through the
> > darlington base which I think the circuit you use might suffer.
> >
> >
> > I posted the schematics of the solarfly and sunflower on my site at
> > http://members.home.net/cybug/solarfly.htm
for you to use if you like!
> >
> > Craig
> >
> > ----- Original Message -----
> > From: Wilf Rigter
> > To:
> > Sent: Tuesday, November 16, 1999 10:45 AM
> > Subject: RE: Cholroplast thingy
> >
> >
> > This may work but it is untested. The PD or green LEDs act as
> photovoltaic
> > generators and steer the 100K resistor current to the MPSA12 with the
> > lower
> > light level. Try adding a little positive feedback by crosscoupling the
> > collectors to the opposite bases.
> >
> > Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
> > tel: (604)590-7493
> > fax: (604)590-3411
> >
> > <>
> > > -----Original Message-----
> > > From: Richard Caudle [SMTP:richard@cqc.com]
> > > Sent: Saturday, November 13, 1999 10:15 AM
> > > To: BEAM
> > > Subject: Cholroplast thingy
> > >
> > > _____
> > >
> > >
> > > Good day, BEAM cats!
> > >
> > > I'm building some Christmas presents and I've hit a bit of a snag.
> > > Attached is the hookup of the thing that I'm working on at the moment,
> > but
> > > both motors won't run. All that runs is one of them. If I unplug the
> > > running one, the non-running one runs. The motors that I'm using are
> > from
> > > CDROM drives. I think they are the ones that eject the CD. Any
> > > suggestions?
> > >
> > > Richard Caudle
> > > www.geocities.com/frankendaddy <http://www.geocities.com/frankendaddy>
> > > Home ICQ - Frankendaddy
> > >
> > > Guardians of the sacred words: Nee, Ptang, and NeeWhon! << File:
> > > chloroplast2k.bmp >>
> >
Attachment: pcse.gif
Home