Hi,
> OKay, the FLED SE is a solar engine that excludes the CMOS 1381J and uses a
> flashing light emitting diode to regulate the capacitor storage. How in the
> blazes does this work out. I'm not all to sure on the specs of a FLED and was
> wondering if someone could (dare i say it) shed some light on the subject.
> I'm trying to work on three projects at the same time, so my messages have
> been a little scatterbrained lately.
To understand this we have to delve a little bit into how a solar engine
works. Just for the record: a Solar engine is a device that allows a high
current device (such as a motor or the like) to be powered by a low
current supply (such as a solar cell). A solar cell might be able to
provide a milliamp or so under good light, but the motor draws tens of
milliamps! How can this work?
The secret is to not have the motor on all the time. If you put a storage
device in between the solar cell and the motor, then the solar cell can
charge the storage device up constantly, and the motor can take little
'sips' of the available charge.
So now we come to the fun part: getting a solar engine to work. The
hardest part of designing a solar engine is the voltage sensor. This part
will 'turn on' when the voltage on the cap rises to a certain value. An
easy solution is to use something designed for this purpose: a 1381
trigger. But there are other (cheaper!) ways of doing this...
A red FLED will 'turn on' at about 1.8 or so volts - that is, it will
allow current through it when the voltage across it reaches that value.
So a FLED solar engine will take that current as it's trigger to turn the
motor on. So when the voltage across the FLED reaches 1.8 volts, the
FLED turns on, which turns on the trigger, which turns on the motor
driver, which turns on the motor. Once the motor is connected, you run
out of voltage very fast. The motor is sucking juice like it's going out
of style, which means the voltage across the cap drops VERY quickly. When
the voltage across the cap reaches 0.8 volts or thereabouts, the trigger
turns off, the motor turns off, and the solar cell gets to try to fill the
cap up again.
So even if the solar cell is capable of supplying 5 volts, it will never
get there because the motor will turn on way before the voltage even
reaches 2.5 volts.
For a 'better' FLED circuit, visit
http://wollongong.apana.org.au/~ben/fred/
This circuit works well at low light levels. Check out the seaplane as
well for another implementation of this circuit.
Ben
10301 Wed, 16 Feb 2000 17:41:35 EST [alt-beam] reverser, resistors stuff beam@sgiblab.sgi.com StickG@aol.com I'm still in the planning stage for my walker (two motor bicore) and I
have a question I hope someone out there can help me with.
On Ian's Beam-online site, there is a reverser circuit for a bicore, but
it is just labelled with inputs and outputs, no specifics. How does this
connect to the bicore?
Also, is there a way to make the touch sensors behave like variable
resistors, so that the walker will turn when it hits something and not just
back up? maybe that's a dumb question. (as i've said before, please use "see
spot run language" , so that I and all the other slow witted people can
understand)
thanks
stick
10302 Wed, 16 Feb 2000 17:47:20 EST [alt-beam] FLED SE q's a'ed beam@sgiblab.sgi.com BUDSCOTT@aol.com thx for the helpful answers on the intricacies of the SE. I plan on building
a small symet with the FLED circuit i've been talking about. i have finally
gotten all the SE parts except for the 3 1000uF caps. I've had a small tape
player motor lying around for quite some time now and want to put it to work.
Thx for all the help.
-Spencer
10303 Wed, 16 Feb 2000 16:28:29 -0700 Re: osciloscope beam@sgiblab.sgi.com = Blumojo13@aol.com =
http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/oscilloscope.html
http://www3.ncsu.edu/ECE480/scope1.htm
These are the only scope sites I have. Hope it helps.
Blumojo13
content-transfer-encoding: quoted-printable
>
http://progdev.sait.=">http://progdev.sait.ab.ca/cmph200/cmph227.htm">http://progdev.sait.=
ab.ca/cmph200/cmph227.htm
There are also a few student reports on this site which are not warran=
tee'd =
to be accurate
Hope this helps
Craig Maynard
JCM Electronic Services
3335 Caribou Drive =
NW
Calgary, Alberta, Canada T2L-0S4
">http://www.robotgames.com">http://www.robotgames.com
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0p=
x; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
Sent: Tuesday, February 15, 2000 5=
:43 =
AM
Subject: Re: osciloscope
href=3D"http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/oscilloscope=
.html">http://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/oscilloscope.ht=
ml
href=3D"http://www3.ncsu.edu/ECE4=">http://www3.ncsu.edu/ECE480/scope1.htm">http://www3.ncsu.edu/ECE4=
80/scope1.htm
These =
are the only scope sites I have. Hope it =
helps.
&nb=
sp; =
&nb=
sp; =
Blumojo13
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