[Noisebridge-discuss] An introduction, and a plea for help with electrical systems

[jim]

comments interspersed below. 


On Tue, 2008-12-23 at 15:04 -0800, Christie Dudley wrote:
> Hi John,
> 
> I'm also interested in helping out here.  I worked on the electrical
> systems for Mutopia last year, so I have a fair idea of what is and is
> not possible with playa conditions.  It sounds like Jim is really
> knowledgeable about the power delivery and I think I could learn
> something from him.
> 
> Regular LEDs should low power enough that you can use smaller
> batteries to run them.  While the Luxeon packaging is pretty
> attractive for fixed installations, it's not something I recommend an
> artist drop that kind of money on.  

what is the purpose of the luxeon devices? 
what is meant by "display light"? 


> There's a crazy variety of cheap LEDs to be had on Ebay.  This past
> year I picked up some high brightness/narrow angle ones and realized
> that a single LED made a very effective flashlight.  You might use a
> narrow-angle like that to illuminate any text you wanted to include
> and possibly spotlight the art.  Using wide-angle LEDs, you could
> create a nice glow effect.  Also, by connecting them up with light
> pipes (acrylic or resin) you can create some pretty dramatic effects.

   it's possible that the number of LEDs required 
justifies buying from electronic distributors (or 
other wholesalers). one of the possible downsides 
of buying from scrapheaps and other such (e.g. ebay) 
is that you can't get enough of a particular thing 
to make a design cost-effective: you have to piece 
together various things to get an effect, and for 
multiple similar effects, you can't find enough like 
things, so you spend a lot of time and materials 
making a bunch of approximately similar one-offs. 
   consider investigating LEDs through distributor 
catelogs (e.g. jameco, digikey, mouser, and many 
others). 

   also, what's the reflectivity of the concrete 
(or whatever material used for the columns)? is 
it possible to add pigments and/or reflective 
sediments to improve the reflectivity of the 
columns? 


> I wouldn't even consider having a "centralized" power source for this
> sort of installation.  You'd lose more energy across the cable than
> you'd actually be using.  Then you'd have to consider the cost of the
> cable.  The copper that would require isn't cheap (or lightweight!).
> And once you've got it all to the playa, you'd have to worry about
> trenching... for up to two miles...  And you thought lugging batteries
> around was a pain!  (Not to mention making the playa resto people very
> unhappy.)

very good points! 


> One of the more popular ways to power stuff on the playa is via
> "retired" UPS batteries.  Most I've seen are about 2" x 5.5" x 4" and
> about 5-6 lbs each, although there is some variation in size.  It's
> possible to get them for free if you get the word out and have enough
> time, since it's a regular service policy that they have to be
> replaced every few years, lest they fail at critical times and it's
> fairly expensive to dispose of them.  Most batteries that come out of
> UPSs are still perfectly good for this kind of application.

   great idea! even though this runs counter to the 
don't-buy-onesy-twoesy ideas (above), it works 
because getting lots of 12VDC batteries is easy and 
it doesn't matter their capacity, just that their 
form-factor is within the space limits. 


> Although I'd be a bit concerned about fitting them inside a 5" column.
> They really should sit flat.  You could potentially use smaller
> batteries if you got the power requirements down, but that's really
> dependent on how much illumination you'll need, and how it's
> distributed.  Lighting design probably should be something that
> involves sitting down with drawings, etc. etc.

   more good points. batteries should be upright. 
there are sealed batteries, but although they 
don't (normally) allow seepage, their internals 
are essentially the same as unsealed batteries: 
the chemical solution is in a cell that should 
be normally oriented (upright). 
   again, you can stack multiple small batteries 
within the columns' internal cavities, and the 
batteries can be different sizes as long as 
they're all the same voltage. 
MORE_BATTERIES == MORE_POWER 
   note there are charging and current draw 
problems that can occur, but they're not 
insurmountable and not expensive (tho' maybe 
a little time consuming soldering together 
a few electronic parts for each required 
control circuit--maximum number is one for 
each battery, probably can be much fewer). 
   also, if batteries are used, you should know 
the temperature extremes, both hot and cold, 
in which they'll be working. that will have a 
bearing on power draw and recharging. 
   seems the most important data point to nail 
down is the luminosity: how lit do the columns 
need to be to be seen from how far away? from 
that it seems you can figure power requirements. 


> Christie
> 
> 
> On Tue, Dec 23, 2008 at 12:30 PM, jim <jim at well.com> wrote:
>         
>         questions
>         
>         about #1 below:
>           seems you want columns lit all night long, yes?
>         
>         about #2 below:
>           if columns must appear monolithic, i guess there'd
>         be no holes to allow air currents through to power
>         the fans of a windmill. the 8" by 8" top would support
>         a very small solar panel, probably not worth the
>         effort, though a matter of battery capacity (would
>         a solar panel charge enough to help get the battery
>         through a second or third day).
>         
>         about #3 below:
>           sounds like multiple batteries in parallel inside
>         the columns.
>         
>         about #4 below:
>           a luxeon flat panel display is used for GUI,
>         picture, and video images. it doesn't seem appropriate
>         unless it's connected to a computer or DVD play or
>         some other device that presents images to the display.
>         will one or more columns have such devices that present
>         images to the flat panel display?
>           i'd consider using just LEDs of various kinds for
>         all lighting, possibly in conjunction with circuit
>         boards that manage power delivery. these are easy
>         to design and make.
>         
>         about #5 below:
>           seems the overall distance approaches two miles,
>         yes?
>         
>         about generators:
>           a 600 foot cable run will drop voltage (and power),
>         though probably not so much that you can't use it.
>         cables and their connectors that are designed for such
>         generators will withstand sun and water, though
>         they're expensive.
>           honda and other companies make generators that
>         put out 15 or more Amps of 120 VAC; these cost in the
>         high hundreds or low thousands of dollars. how to
>         manage them: refill fuel, turn them on and off at
>         appropriate times during the day...? and how to
>         protect them from theft?
>           given 41 columns spaced in a row that spans two
>         miles, how to configure cable so that the generator
>         can power multiple columns simultaneously?
>         
>         
>         
>         
>         On Tue, 2008-12-23 at 11:59 -0800, Morley John wrote:
>         > Jim,
>         >
>         > A few comments:
>         >
>         > 1) Yes, we can replace the batteries. If we go the battery
>         route, we
>         > are prepared to procure two sets of batteries - one to sit
>         on a
>         > charger for a day or two, one to sit in the columns. **We
>         don't want
>         > to swap battery arrays every day**, though - that would
>         majorly suck.
>         > I've maintained battery banks for burning man art
>         installations
>         > before, and it's a huge chore. They're heavy, and a pain to
>         lug
>         > around!  Swapping batteries every 3 days would be optimal.
>         So figure
>         > we would need to design for 30 hours of runtime
>         > (3x10-hours-of-darkness nights, based on civil twilight
>         hours).
>         >
>         > 2) Windmills aren't really possible, as they would seriously
>         detract
>         > from the column layout. Solar panels atop the columns, 8"x8"
>         square,
>         > are possible but I worry they'd be cost prohibitive, and not
>         really
>         > charge up the batteries enough to make a difference....?
>         >
>         > 3) We will be casting the columns around hollow cardboard
>         tubes,
>         > allowing for room inside the columns themselves to hold
>         batteries.
>         > They will be protected from the elements, and the playa is a
>         very dry
>         > environment. They're space constrained, though - an 8"
>         column has, at
>         > most, a 5" tube at its center.
>         >
>         > 4) As for the luminosity, it's hard for me to describe. I'm
>         not
>         > familiar with the technical parameters of lighting, really.
>         I can give
>         > you a comparison, though. If we could power something akin
>         to a single
>         > low-wattage (5watt?) compact fluorescent bulb to light the
>         display,
>         > two very bright strobing lights at the top of the column
>         that would be
>         > visible from 1000 feet, and a handful (say, 15 to 20?) small
>         "accent'
>         > LEDs, I'd be happy. It's the display light I most worry
>         about - a
>         > single Luxeon flat panel seems to be a huge energy draw. I
>         can't
>         > imagine adequately lighting a 12"x8"x8" sculpture, in the
>         middle of
>         > the night in the middle of nowhere, with one LED, even if it
>         is a
>         > luxeon. So we increase to 4 luxeons per column.. that's a
>         lot of
>         > juice!
>         >
>         > 5) 41 columns. Spacing of the first 11 columns varies from
>         about a
>         > hundred feet up to 1000 feet. Spacing of the last 30 columns
>         is much
>         > tighter - average of 20 feet apart, max 50, min 5.
>         >
>         > So, who knows something about running 600 feet of electrical
>         wiring
>         > from a generator? Can it be done without too much decrease
>         in current
>         > over that distance?
>         >
>         > We are in the cost proposal stages right now. This will be,
>         hopefully,
>         > funded by the burning man organization, so cost is fairly
>         flexible.
>         > We're looking at a total project budget of at least $8,000.
>         Probably
>         > more like $10k-$12k, what with transportation costs etc. (41
>         concrete
>         > columns would seem to require a flatbed semi...)
>         >
>         > -Morley
>         >
>         > "How do I stop being afraid? Know that there is no safety
>         anywhere.
>         > There never was and there never will be. Stop looking for
>         it. Live
>         > with a fierce intent to waste nothing of yourself or life."
>         - Ann
>         > Shulgin
>         >
>         >
>         >
>         > On Tue, Dec 23, 2008 at 11:29 AM, jim <jim at well.com> wrote:
>         > >
>         > >   your project seems interesting to me. i have
>         > > some experience with low voltage systems and
>         > > electronics as well as having worked some years
>         > > as an electrician. i would like to help out.
>         > >   it would help to have exact specs for the
>         > > power needs. how many columns? what distance
>         > > apart? what luminosity needed? describe the
>         > > overall installation from the spectators'
>         > > point of view, please. anything requiring
>         > > power other than lights?
>         > >   batteries are the likely right power source.
>         > > in general terms, the battery should have
>         > > sufficient capacity to provide power for about
>         > > 24 hours. recharging the battery should be
>         > > done by solar panels and/or windmill generators.
>         > > recharging devices should be powerful enough to
>         > > recharge sufficiently within six hours on a dim,
>         > > windless day.
>         > >   is it possible for someone manually to
>         > > replace batteries at some time during the days?
>         > > if so, batteries may be swapped out and
>         > > recharged at some other location. consider an
>         > > electronic circuit that manages how the system
>         > > uses power along with managing recharging.
>         > >   from a mechanical point of view, water and
>         > > sunlight are enemies: wires and cables should
>         > > be UV insensitive and connections sufficiently
>         > > water-resistant not to allow electrical
>         > > conduction between a battery's two terminals.
>         > > given that you're casting the columns, you
>         > > can probably have a cavity that provides
>         > > appropriate shelter and exposure.
>         > >   all of the above is doable with standard
>         > > stuff. the difficulty will likely be trade-offs
>         > > in parts capabilities vs costs. i.e.
>         > > MORE_MONEY == MORE_EASY
>         > > jim at well dot com
>         > >
>         > >
>         > >
>         > >
>         > > On Tue, 2008-12-23 at 10:00 -0800, Morley John wrote:
>         > >> Hi there!
>         > >>
>         > >> I'm Morley. I already know some of you (Rubin, Audrey,
>         who else?)
>         > >> through NIMBY/Interpretive Arson. To the rest of you,
>         greetings! I've
>         > >> been by the space once to check it out and was quite
>         inspired. Glad to
>         > >> see people throwing their energies into all sorts of
>         fascinating
>         > >> endeavours :)
>         > >>
>         > >> I write not just to introduce myself, but to introduce a
>         project I'm
>         > >> working on, and to hopefully recruit some interested
>         folks to help
>         > >> out.
>         > >>
>         > >> The project, working title Timescale, is a scaled
>         representation (time
>         > >> scaled to distance) of the last 4.57 billion years of the
>         history of
>         > >> the planet Earth. It will be installed at Burning Man in
>         2009. The
>         > >> installation will measure exactly one mile from end to
>         end, starting
>         > >> with the Cryptic Era at the beginning of the formation of
>         the planet,
>         > >> and finishing with the Holocene Epoch, the 11,430 years
>         since the last
>         > >> ice age.  The beginning of each Precambrian Era and
>         Cambrian Epoch
>         > >> (see: http://www.stratigraphy.org/chus.pdf ) will be
>         marked with a
>         > >> concrete column, 8"x8" square, rising up from the playa.
>         Atop the
>         > >> column will be a clear polycarbonate box that holds a
>         sculpture
>         > >> evoking some element of
>         geologic/biologic/evolutionary/climate history
>         > >> from that period of geologic time.
>         > >>
>         > >> The columns will be fabricated at the new NIMBY2 - anyone
>         who wants to
>         > >> learn about casting lightweight concrete, you're welcome
>         to come help
>         > >> out!  Fabrication will begin in earnest this spring.
>         > >>
>         > >> But the more pressing issue, and the one I suspect is
>         more up the
>         > >> alley of folks on this list, is how to power these
>         columns.  For each
>         > >> column we'll need to light the sculpture (luxeons? 5W
>         compact
>         > >> fluorescents?), light the explanatory text on the sides
>         of the
>         > >> columns, and power some sort of strobe/floodlight atop
>         the column so
>         > >> you can see them from afar.  In the Precambrian, there's
>         up to 1000
>         > >> feet between columns. (The entire Cambrian, on the other
>         hand,
>         > >> representing the vast majority of the evolution of
>         Earth's biological
>         > >> diversity, is 660 feet long).
>         > >>
>         > >> Sets of small 7AH to 12AH batteries in each column? (No,
>         we will not
>         > >> put a deep cycle next to each column, they must be
>         stand-alone). A
>         > >> generator and a mile of trenched wiring? A generator
>         powering just the
>         > >> Cambrian, batteries in the Precambrian? A quick
>         calculation indicates
>         > >> that four luxeons will burn out a 7AH battery in about
>         two hours,
>         > >> leading me to think that pure battery power is untenable.
>         What we
>         > >> really need is an electrician to help us figure all of
>         this out.
>         > >>
>         > >> I am far from an electrician - as you might have guessed,
>         I'm
>         > >> primarily a geologist.  If any of you have experience
>         with such things
>         > >> and would like to help us figure out our power systems,
>         we'd be most
>         > >> grateful. (We being myself and my co-conspirator, Flint
>         Hahn). And of
>         > >> course, down the line we'll need plenty of help
>         constructing the
>         > >> actual lighting assemblies for each column. And if anyone
>         wants to
>         > >> claim a column and create a sculpture, great! We'll be
>         putting out the
>         > >> general call for column artists in a few months, once we
>         have funding
>         > >> secured.
>         > >>
>         > >> Thanks for reading, and I look forward to meeting more of
>         you in the future!
>         > >>
>         > >> Cheers,
>         > >>
>         > >> Morley
>         > >>
>         > >>
>         > >> "How do I stop being afraid? Know that there is no safety
>         anywhere.
>         > >> There never was and there never will be. Stop looking for
>         it. Live
>         > >> with a fierce intent to waste nothing of yourself or
>         life." - Ann
>         > >> Shulgin
>         > >> _______________________________________________
>         > >> Noisebridge-discuss mailing list
>         > >> Noisebridge-discuss at lists.noisebridge.net
>         > >>
>         https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>         > >>
>         > >
>         > >
>         >
>         
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> You can't learn what you think you already know.