Alt-BEAM Archive
Message #10530
To: beam@sgiblab.sgi.com
From: "Sathe Dilip" sathe_dilip@bah.com
Date: Sun, 20 Feb 2000 17:36:21 -0500
Subject: [alt-beam] Re: More fun questions
Bob,
If you look at my messages, you will see that I am writing about testing
the solenoid only. We were not discussing about the application. In a
way, by designing your circuit for the worst case current possible, your
circuit (& you) are safer.
Dilip
-------------------------------------------------------------------
Bob Shannon wrote:
>
> Sathe Dilip wrote:
>
> > Using the ohms range of your multimeter, measure the resistance of the
> > solenoid coil. Divide the voltage you want to apply by this value in
> > ohms. You will get the value of current required to drive the solenoid
> > from a DC source.
> >
> > e.g.,
> >
> > You want to drive the solenoid with 3 volts.
> > You measure the coil resistance as 6 ohms.
> >
> > You will draw 3/6 = 0.5 Amps for the solenoid.
> >
> > Dilip
>
> This is not quite right. The DC resistance of the coil
> neglects its high inductance. This inductance will keep
> the current down well below the value calculated above.
>
> Of course the cap voltage will be falling rather quickly
> as well, so the peak current will never reach about half
> the value you might expect from the DC resistiance.
>
SNIP
----------------------------------------------------------------------
The early bird may get the worm, but the second mouse gets the cheese.
----------------------------------------------------------------------
10531 Sun, 20 Feb 2000 17:45:42 -0800 [alt-beam] Re: solarbotics pager mtr+fan beam@sgiblab.sgi.com Laura Malinowski Laura/Rob Malinowski Tim,
As a "newbie" I have only shot off my mouth a couple of times (I am usually
known for this). But this time I must say WRONG! This is a great discussion
for BEAM. I have only made a few bots but now I have an idea to (hopefully)
make some fly. At the rate these guy are talking about this I'm sure a few
others are working on designs also or will be soon.
You never know where that next great idea will come from.
A journey of a thousand miles begins with one step.
Rob M.
Timothy Flytch wrote:
> I feel I must apologize to the list for starting this thread...
> Sorry...
> I will only address non beam topics off list...
> If you do not know how to do this it is simple just cut out my url and
> plaste it into the "To: " ... I would be more than happy to entertain any
> aviation related discussion... BUT NOT ON BEAM!!!!
> Again, Sorry BEAMers...
> Timothy...
>
> >At 07:49 AM 2/20/2000 , Bob Shannon wrote:
> >>Ahhh, can you list production aircraft with counter-rotating props?
> >>
> >>And how many more can you lise with both props rotating in the same
> >>direction?
> >
> >One jumps to my mind: the V-22 OSPREY tilt-rotor. Oh, and the Piper
> >Seminole (still in production? Dunno...) And (outside the requested spec)
> >originally, the Wright Flyer, and more notably in WW2, the P-38 Lightning.
> >
> >Granted, it is NOT very prevalent because the added expense of a 2nd
> >gearbox and 2nd type of propeller. BUT, if you look at the boating
> >industry, there are many twin-engine designs using counter-rotating
> >propellers, for the same reason - torque steer cancellation.
> >
> >Regards,
> >Dave
> >---------------------------------------------------------------
> >"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
> >that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
> > 2 vowels. Pronounciation? _SMITH_".
> > http://www.solarbotics.com
>
> ______________________________________________________
>
10532 Sun, 20 Feb 2000 17:48:14 EST [alt-beam] More solenoid junk beam@sgiblab.sgi.com BUDSCOTT@aol.com Right so the solenoids do actually work in my circuit. its just that even
thought they are three volt solenoids, my circuit just doesn't have the balls
to drive it. i was thinking about what somebody said earlier, camera shutter
release solenoids. has anybody tried these, or even seen one. i was wondering
if they were in disposable cameras. cause then i could just walk over to the
photo place and ask if they had any empty disposable cameras that i could get
parts from. these would definitly be more efficient than my surplus store
ones. thanks for any response
-Spencer
10533 Sun, 20 Feb 2000 16:09:06 -0700 [alt-beam] Re: Breadboarded solenoids beam@sgiblab.sgi.com Dave Hrynkiw At 03:25 PM 2/20/00 , BUDSCOTT@aol.com wrote:
>well, i breadboarded (or protoboarded, whatever) the solenoid photovore that
>i've been working on. now i swear i saw the solenoids triggier once, but then
>i couldn't get them to trigger.
What sort of SE are you using, a 1381 SE, or a D1 style? If the 1381 "2
transistor" type, it may be still latched on, not resetting. Try a smaller
solarcell or decreasing your light levels just to make sure it's having a
chance to reset.
Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com
10534 Mon, 21 Feb 2000 10:55:58 +1100 (EST) [alt-beam] Re: Breadboarded solenoids beam@sgiblab.sgi.com Ben Hitchcock First off,
I would try to replace the SE with my finger. By that I mean hook up the
cap and the solar panel in parallel, wait for abit until the cap charges
up to a decent voltage, then connect the solenoid and see what happens.
If the solenoid moves, then well done! Replace your finger with a SE and
go from there.
If it doesn't move, then, well, get some bigger caps or try something
else.
Like Dave said, the 1381 circuit needs to be pulled down to 0.7 volts
before it will reset. If the circuit is stabilising at 1 volt or so then
you need a different circuit for your SE. Check your solenoids first.
Ben
> well, i breadboarded (or protoboarded, whatever) the solenoid photovore that
> i've been working on. now i swear i saw the solenoids triggier once, but then
> i couldn't get them to trigger. i've got the circuit all hooked up correctly
> as well as the solenoids. i've got two 4700uF caps hooked in parrallel, 1381L
> (3.0-3.3v), and a large 5.5v solar panel, but the piece of #$%& still won't
> work! i realize that transistors limit the current somewhat from the current
> going to the base, but i still think that it would trigger the #$%&
> solenoids. Patients is a virtue, or an asset, i cant remember which, any
> insight? Thanks o ton for help!
>
> -Spencer
>
--
Nothing is foolproof to a sufficiently talented fool.
10535 Sun, 20 Feb 2000 19:09:32 EST [alt-beam] Re: FYI: ANN: fire-fighting robot contest at Penn State (3-25) beam@sgiblab.sgi.com CIRCITZ@aol.com I didn't think that this particular contest was for a team of robots, but
maybe I misread the rules.
<< I actually was talking about a team of robots, but I wouldn't mind
collaborating with other people.
>>
10536 Sun, 20 Feb 2000 19:05:21 -0500 [alt-beam] Re: Geared motors...again "William Cox" So would these be good or not??
-William
> #650-0671 $1.99 Gearhead motor 2 D cells (3V) and
> #650-0676 $2.99 Two 30RPM gearhead motor 4 D cells (6V or possibly 3V
each?)
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