Chip with simple program for Toy

[Daniel T.]

<http://www.ec.gc.ca/nopp/docs/rpt/battery/en/c7.cfm>
Since the first battery prototype developed in the late 19th century,
the basic battery design has not changed significantly; only the
chemistries have evolved. Introduction of new chemistry composition,
such as lithium ion, has improved battery life but has not solved the
demand. In fact, for most batteries, it is believed that they have been
optimized to reach their maximum output and lifespan. This especially
applies to primary batteries and nickel cadmium (NiCd) batteries.
Conventional batteries are falling behind the demand for more battery
"juice". It does not appear, however, that the lithium-ion battery has
reached its maximum charge limit. Recent announcements by Sony and
Matsushita (which makes Panasonic batteries) claim to have improved the
life of the lithium-ion (Li-ion) battery by up to 30%.

<http://www.ec.gc.ca/nopp/docs/rpt/battery/en/c7.cfm#s7_3>
To date, there have been no revolutionary advancements in battery
design, but this may soon change with the introduction of the micro fuel
cell battery. In recent years there has been a flurry of activity as the
battery industry focuses its research efforts on the micro fuel cell.
The fuel cell shows promise in being able to deliver higher energies
over a longer period of time. Instead of hoping for a laptop that stays
charged for eight hours, fuel cell proponents are hoping that battery
life can increase two to ten fold. It is estimated that more than 60
companies are competing to develop the micro fuel cell battery,
including IBM, Motorola, Toshiba and NEC.

 

[Kitty]

"Daniel T." <daniel_t@earthlink.net> wrote in message
news:daniel_t-FB2206.11461717082008@earthlink.vsrv-sjc.supernews.net...

http://www.ec.gc.ca/nopp/docs/rpt/battery/en/c7.cfm
Since the first battery prototype developed in the late 19th century,
the basic battery design has not changed significantly; only the
chemistries have evolved. Introduction of new chemistry composition,
such as lithium ion, has improved battery life but has not solved the
demand. In fact, for most batteries, it is believed that they have been
optimized to reach their maximum output and lifespan. This especially
applies to primary batteries and nickel cadmium (NiCd) batteries.
Conventional batteries are falling behind the demand for more battery
"juice". It does not appear, however, that the lithium-ion battery has
reached its maximum charge limit. Recent announcements by Sony and
Matsushita (which makes Panasonic batteries) claim to have improved the
life of the lithium-ion (Li-ion) battery by up to 30%.

http://www.ec.gc.ca/nopp/docs/rpt/battery/en/c7.cfm#s7_3
To date, there have been no revolutionary advancements in battery
design, but this may soon change with the introduction of the micro fuel
cell battery. In recent years there has been a flurry of activity as the
battery industry focuses its research efforts on the micro fuel cell.
The fuel cell shows promise in being able to deliver higher energies
over a longer period of time. Instead of hoping for a laptop that stays
charged for eight hours, fuel cell proponents are hoping that battery
life can increase two to ten fold. It is estimated that more than 60
companies are competing to develop the micro fuel cell battery,
including IBM, Motorola, Toshiba and NEC.

There are advances in solid state & thin film batteries. Check out the
technologies of

www.excellatron.com


Kitty

 

[Rod Speed]

RLDeboni <robertodeboni@deboni.name> wrote:

Rod Speed wrote:
RLDeboni <robertodeboni@deboni.name> wrote
Rod Speed wrote
RLDeboni <robertodeboni@deboni.name> wrote

Take a MAN 5S50ME-C7 low speed engine.
95 RPM, 3'800 kW power, 159 gr/kWh specific fuel oil consumption
...snip...
In one day, consumption is 14'501 kg fuel oil and electricity
production is 86'640 kWh.

Let us forget that fuel oil is neither gasoline nor diesel fuel.
Let us say that with 1 kg of fuel we make 10 miles.
So with 14'501 kg fuel, we do 145'010 miles

Le us say that we power 1'000 homes, each one with one car.
If every home gets 14,5 kg fuel, an ICE engine car could make 145
miles a day.

Instead, say that every home get's 87 kWh of electricity.
Tesla Roadster charging efficiency is 86%.
That's 87 * 0,86 = 75 kWh, enough to fully charge 1,4 times.
Tesla Roadster range is 221 miles on the EPA combined cycle.
That's 1,4 * 221 = 309 miles ... double the milage of an ICE
engine car.

Or we can power 1'000 cars 221 miles each and 22 kWh free
electricity (forgetting the power plant price ;-) for each home.
In winter the power plant could additionally give some 40 kWht of
waste heat for heating (say about 30 kWht losses) and warm water.
In summer, the waste heat could be used for a 300 kW ORC plant,
and luke warm water for the homes. That is cogeneration + combined
cycle.

May I say: 75% efficiency ?

No you cant, thats a complete wank.

Electricity (50%) +

Combined Cycle (+5%) +

like the BMW concept:

http://en.wikipedia.org/wiki/Turbosteamer

With a stationary plant we don't have weight and size problems.

Home Heating (+20%)

recovered waste heat.

You're ignoring the power station inefficiency with electricity.

Ignoring 50% ?

Thats not the power station inefficiency, thats the charge discharge inefficiency.

You cant do that.

Sorry, but I don't understand.
What I can not do ?

Ignore the power station inefficiency with electricity.

 

[Rod Speed]

Daniel T. <daniel_t@earthlink.net> wrote:

Doug Houseman <doug@msen.com> wrote:

facts snipped...

Here's another one:

http://www1.eere.energy.gov/windandhydro/pdfs/41869.pdf
"20% Wind Energy by 2030: Increasing Wind Energy's Contribution to
U.S. Electricity Supply"

Just a number plucked out of someone's arse. We can tell from the smell.

 

[Rod Speed]

Bret Cahill <BretCahill@aol.com> wrote:

Locking in anything, particularly power generation, to what is known
at any one time, like the present, is a mistake, at best.

Electricity specifically being something wide open to new discovery
as it itself is new in terms of human ability to know enough to
manipulate it. Solar is in the wings. They both should have been
coming center stage 30 years ago.

What's really inexplicable is that it's nearly impossible to find
anyone, even here on newsgroups, who will deny future advances in
battery technology will be significant.

It's common for the majority but rare for _everyone_ to be hopelessly
optimistic. Even nuclear has a nut case poster with a junk science
"proof" that controlled fusion is impossible on earth.

Where can we find a proof on battery limits?

You cant find 'proof' on any relevant 'limits' except thermodynamics etc.

 

[Rod Speed]

Kevin Aylward <kaExtractThis@kevinaylward.co.uk> wrote

Rod Speed wrote

That is, the ability to generate truly new ideas, not based on prior inputs.

You havent established that that has anything to do with random processes.

Oh dear....here we go again...

Oh cheap....yeah, you've never had a clue.

There are two options:

Wrong, as always.

1 A new idea is derivable from existing ideas - i.e. not intrinsically new

2 A new idea is not derivable from existing ideas - i.e. intrinsically new

Its almost never that absolute.

Even with say DNA, its just an alternative idea about how the new
individual's config is determined, an alternative to Lanarkism for example.

If "1" is correct for an idea, then by construction it is not a new idea, it is simply a logical consequence of
existing traits.

Irrelevant to what is being discussed, whether there is any RANDOM process involved.

If "2", the idea is new, that is not derivable from existing traits, then that idea must therefore be non predictable.

Irrelevant to what is being discussed, whether there is any RANDOM process involved.

However, a non predictable trait is, essentially, a random trait, by definition.

Wrong, as always. Nothing 'random' about the idea that the speed of light is invariant for example.

And even if that was true, thats only a tiny subset of worthwhile new ideas anyway, so you STILL havent
established that there is any RANDOM process involved with the vast bulk of worthwhile new ideas.

************************

It is trivially obvious that if an "idea" was, in actual fact, generated from a random process,

You aint established that ANY of them actually are.

and if such a generated idea, does not, by chance duplicate an already existing idea,

Thats by definition not a NEW idea, what was being discussed.

then it is logically a necessity that such an idea must be classed as truly new.

Its truly new even if it isnt generated from a random process.

i.e one that is not derivable, as this is part of the very definition of a random process.

Utterly mangled all over again.

And this is an absolutely classic circular 'argument' anyway.

That is, a new idea is logically sufficient, and explainable from a proposal that the new idea is a result of a
random process.

Just claiming that doesnt establish that.

Although, in practice, it is usually a random variation,

You aint established that either.

of a highly selected, (non random) process, e.g, highly filtered white noise,

Or that.

but this does not negate the required random component.

You aint established that there is any random component.

Thus, I have established the sufficiency that a randomly generated idea can generate truly new information.

No you havent, even with non derivable new ideas.

And those are only a tiny subset of the worthwhile new ideas being discussed anyway.

Now, is it a necessary condition that a truly new idea must have a randomly generated component.

Wrong again. And we werent JUST discussing your 'truly' new ideas, we were discussing ALL worthwhile new ideas.

<reams of your completely irrelevant waffle flushed where it belongs>

 

In sci.physics Jerry Kraus <jkraus_1999@yahoo.com> wrote:

On Aug 16, 5:32?pm, zinnic <zeenr...@gate.net> wrote:
On Aug 16, 9:40?am, Jerry Kraus <jkraus_1...@yahoo.com> wrote:


Despite the braying of naysayers scientists continually prove them
wrong! Example- DNA research will have no utility, Crude flying
machines will never be useful for transport. The list goes on and on.-

Ummm....The science of Genetics, the basis for DNA research, was
developed by Gregor Mendel, a Monk and Abbott, not a professional
scientist. The airplane was invented by the Wright brothers, bicycle
mechanics, not professional scientists. My criticisms are not of the
process of science, or the concept of science, but of the professional
scientific bureaucracy, specifically. Which I consider to be
exceedingly self-serving, inefficient, and corrupt.

Neither of you seems to know the difference between science and
engineering.


--
Jim Pennino

Remove .spam.sux to reply.

 

[Rod Speed]

Jerry Kraus <jkraus_1999@yahoo.com> wrote

zinnic <zeenr...@gate.net> wrote
Jerry Kraus <jkraus_1...@yahoo.com> wrote

Despite the braying of naysayers scientists continually prove them wrong!
Example- DNA research will have no utility, Crude flying machines will
never be useful for transport. The list goes on and on.

Ummm....The science of Genetics, the basis for DNA research,

Nope. Its just what the DNA controls, a different matter entirely.

was developed by Gregor Mendel, a Monk and Abbott, not a professional scientist.

But the discovery of DNA wasnt.

The airplane was invented by the Wright brothers,
bicycle mechanics, not professional scientists.

My criticisms are not of the process of science, or the concept of
science, but of the professional scientific bureaucracy, specifically.

Which does occassionally manage to do something useful, like discover what DNA is about.

Which I consider to be exceedingly self-serving, inefficient, and corrupt.

Everything is all of those to some extent. Most science has a lot less of that than most other areas.

It does however have plenty of mindless fools involved in it, just like every other field does.

 

[Rod Speed]

RLDeboni <robertodeboni@deboni.name> wrote

Rod Speed wrote
RLDeboni <robertodeboni@deboni.name> wrote

Ignoring 50% ?

Thats not the power station inefficiency, thats the charge discharge inefficiency.

Sorry, but that's the power station inefficiency (or efficiency ...
;-)

Varys with the power station technology.

In the example, the Power Station is powered with a MAN 5S50ME-C7 low
speed engine (95 RPM, 3'800 kW power, 159 gr/kWh specific fuel oil consumption):

Thats irrelevant, hardly anyone is stupid enough to do a power station that way anymore.

 

[BobW]

"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message
newsl3ha452f0ibb1g0hbtc4jc01t34408ln8@4ax.com...

On Sun, 17 Aug 2008 12:03:35 -0400, "Kitty" <cowgirla@bellsouth.net
wrote:>There are advances in solid state & thin film batteries. Check
out the
technologies of

www.excellatron.com


Kitty



6 years of research. 10,000 prototypes. Production capacity of 100,000
batteries per month.

You'd think they might have a product one of these years.

John

There's also this company with their silver-zinc battery technology:

http://www.zpowerbattery.com/

The only thing I know for sure is that they're close to where I live. I
don't like going into Camarillo, because every time I do, I start singing
the song Camarillo Brillo by Frank Zappa.

"She had a snake for a pet, and an amulet, and she was breeding a dwarf, but
it wasn't done, yet. She had grey-green skin ... a doll with a pin. I told
her she was alright, but I couldn't come in."

See what I mean?

Bob
--
== All google group posts are automatically deleted due to spam ==

 

[Rod Speed]

Some gutless fuckwit desperately cowering behind
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote just
the pathetic excuse for a juvenile troll thats all it can ever manage.

 

[Rob Dekker]

"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message news:ns0ea4laluuo709fs19ifoc9ddbo6ig2qa@4ax.com...
......

The general idea is that it is easier to control emissions from a few large
power plants running at optimal efficiency than it is to control it from
thousands of vehicle ICEs.

These plants have amazing filter systems. Better than what would be
affordable for automobiles.
Besides that, they run at optimal RPMs, reducing pollutions to a minimum.
That cannot said about automobile ICEs in city traffic.

Rob


A modern gasoline-powered car creates very little pollutants...
essentially zero particulates and low ppm levels of hydrocarbons and
nitrous stuff, probably cleaner watt-for-watt than the average coal
plant.

That's not what the studies say.
Daniel posted a few results in a side thread.

Rob

 

[Rob Dekker]

"Bret Cahill" <BretCahill@aol.com> wrote in message news:7ced8d41-b935-4da6-aeda-5ee73fde9d01@26g2000hsk.googlegroups.com...

Locking in anything, particularly power generation, to what is known at
any one time, like the present, is a mistake, at best.

Electricity specifically being something wide open to new discovery as it
itself is new in terms of human ability to know enough to manipulate it.
Solar is in the wings. They both should have been coming center stage 30
years ago.

What's really inexplicable is that it's nearly impossible to find
anyone, even here on newsgroups, who will deny future advances in
battery technology will be significant.

I agree. I think that there will be great advances (albeit slowly) in battery tech the future, but even so, I don't think that
battery technology is the major limiting factor at this point.
What is lacking is a automotive 'platform' that allows batteries to drive vehicles.

Currently, even if you would have the ideal battery around, there is nothing you can do with it (other than rebuilding your vehicle
completely).
That is because all vehicles sold today the ICE drives wheels directly (via the drive train).
Hybrids (like the Prius) are 'parallel' hybrids, which add a (not so strong) electric motor/generator and add a (not so large)
battery.
That helps a little bit in fuel efficiency (partial regenerative braking mostly) but it also makes the overall system more
expensive.
If you enlarge the battery (for plug-in), you are not adding much value to the vehicle, since the electric motors are a (power)
limiting factor in parallel hybrids (they are not strong enough for normal operation, including normal accelleration and freeway
cruising.

I think we need 'series' hybrids before the role of batteries becomes important.
In series hybrids, electric motors drive the wheels, and the ICE is reduced to a secondary role (auxiliry power unit).
The ICE is much smaller there, and runs much more efficient, and also the stronger electric motor/generators can take more advantage
of regenberative braking.
This not only makes series hybrids up to a factor 2 better (more efficienct) than even parallel hybrids, it also creates a
'platform' for plug-in and even all-electric drive.

For example, if most cars on the road would be series hybrids, then I could imagine a very inexpensive plug-in or all-EV conversion
kits (consisting essentially only of a battery), and this would immediately increase the (electric) driving range, and NOT
compromise on power.
This series hybrid as a platform for automotive design would allow easy 'retrofitting' of batteries on existing vehicles if liquid
fuel again becomes more expensive than electricity or when batteries become better or cheaper than today.

Currently, the decision between battery or gasoline cannot be taken by the car owners, because retrofitting batteries is not an
option.
With series hybrids on the road, even if battery technology would not advance that much, the 'market' (not discussions in this NG
) could decide if battery technology is advanced enough or not.

My 2 cts.
Rob

It's common for the majority but rare for _everyone_ to be hopelessly
optimistic. Even nuclear has a nut case poster with a junk science
"proof" that controlled fusion is impossible on earth.

Where can we find a proof on battery limits?

All batteries have a 'theoretical' upper energy density limit, which is rather easily calculated (at least if you are an electro
chemist).
Currently, most batteries operate far from this theoretical upper limit (often a factor 10 off what is possible).

I actually am looking for scientific papers that explain why they are so far off their theoretical limit, and how to improve on
that.

Bret Cahill

 

[Rob Dekker]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48A74E15.2FFDDA1F@hotmail.com...

Rob Dekker wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote
....
"""
...Although half the [USA] uses coal-fired plants, EVs recharging from
these facilities are predicted to produce less CO2 than ICE vehicles

Who said CO2's the problem or do you just believe everything the news
media says ?


Come on Graham,
Daniel went to great length to shows you results of a list of studies on ALL
kind of pollutants. Not just CO2.
So why you pick out this one ?

Well *I* didn't. You want SO2, NOx, CxHx, particulates or what. Might be best to
state that first.

I wonder if you even read the rest of Daniel's post (after you noticed the letters CO2 reduction in the first lines).
Hint : ALL pollutants are down when we use grid electricity to drive vehicles.

Besides that, with different starting fuels (coal or nat gas->electric->EV
versus gasoline->ICE) it is hard to talk about efficiency differences, but
in absense of any other measure, CO2 emissions overall IS an indication of
efficiency.

Every fuel leaves a different footprint. Concentrating on one alone in isolation
is BERSERK !

Graham

 

[Rob Dekker]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48A7682D.3ACDE0C6@hotmail.com...

Rob Dekker wrote:

"Eeyore" wrote
"""
...Although half the [USA] uses coal-fired plants, EVs recharging from
these facilities are predicted to produce less CO2 than ICE vehicles

Who said CO2's the problem or do you just believe everything the news
media says ?

Come on Graham,
Daniel went to great length to shows you results of a list of studies on ALL
kind of pollutants. Not just CO2.
So why you pick out this one ?

CO2 is vitally essential to life on the planet earth. Theree is NO actual
evidence whatever that increasing levels will cause climate catastrope. That's
purely in the minds of of the doom-mongers like the IPCC who are working on
paper thin weak hypotheses.

That's right. CO2 is not the cause of climate change. Pirates are, as this graph proves :
http://upload.wikimedia.org/wikipedia/en/0/04/FSM_Pirates.png

Rob

 

[Rob Dekker]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48A8E26E.32C635F0@hotmail.com...

Rob Dekker wrote:

I think that there will be great advances (albeit slowly) in battery tech the future,

And why do you think that when the lead acid cell has barely changed in around 100+ years.

and will not for the next hundred. Just like the vacuum tube and the incandecent light bulb hardly changed over the past hundred
years.

Graham

 

[Paul E. Schoen]

"happymac" <harrytuttle777@mac.com> wrote in message
news:g8auhf02l8o@news3.nntpjunkie.com...

Hello,

This problem has probably been debated quite a few times before, but I
would like to get your opinions. I am starting out in electronics, but
would like to know which piece of circuit simulation software I should
use. I am familiar with SPICE, but entering the netlists by hand is
prone to error. I have also used Electronics WB, LT spice (switcher
CAD), and PROTELL 99. I don't mind spending a little bit of money, but
anything over 1K is out of the question, unless I can find a version or
free online.

What software do you think would be beneficial to invest money, and time
into learning


Thanks for any and all opinions.

I like LTspice, and use it for almost everything. It is also useful for
posting schematics on newsgroups, using the ASCII file format.

I have also used Tina, which is available free on the www.ti.com website. I
also purchased a low end version for about $30. It has some cool features
like an interactive mode and clickable components such as switches, that
will cause LEDs to light, relays will change state, displays will indicate
digits and alphanumerics, etc. There is a bit of a learning curve, however,
and I have not used it much, but it's worth a try, especially for some
circuits.

Also check www.tina.com, www.designsoftware,com and www.edisonlab.com. They
have some nice products, including a PCB design package with 3-D views,
virtual instruments, etc.

Paul

 

[Rob Dekker]

"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message
news:rquha4lc1d78js33m69fs46gfnt8f7squr@4ax.com...

On Sun, 17 Aug 2008 19:02:29 -0700, "Rob Dekker" <rob@verific.com
wrote:


"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message
news:ns0ea4laluuo709fs19ifoc9ddbo6ig2qa@4ax.com...
.....
The general idea is that it is easier to control emissions from a few
large
power plants running at optimal efficiency than it is to control it
from
thousands of vehicle ICEs.

These plants have amazing filter systems. Better than what would be
affordable for automobiles.
Besides that, they run at optimal RPMs, reducing pollutions to a
minimum.
That cannot said about automobile ICEs in city traffic.

Rob


A modern gasoline-powered car creates very little pollutants...
essentially zero particulates and low ppm levels of hydrocarbons and
nitrous stuff, probably cleaner watt-for-watt than the average coal
plant.

That's not what the studies say.
Daniel posted a few results in a side thread.

Rob


I haven't seen the studies. But pollution from coal plants is
currently a serious problem. Pollution from modern cars really isn't.

Do you have data to support that statement ?

CO2 is not a pollutant.

That's not what the supreme court says :
http://www.dieselnet.com/news/2007/04epa.php

John

 

[Rob Dekker]

"John Larkin" <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message
news:22vha4tnh270e71gauprvqtha6k8uj1ued@4ax.com...

On Sun, 17 Aug 2008 19:57:08 -0700, "Rob Dekker" <rob@verific.com
wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:48A74E15.2FFDDA1F@hotmail.com...


Rob Dekker wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote
....
"""
...Although half the [USA] uses coal-fired plants, EVs recharging
from
these facilities are predicted to produce less CO2 than ICE
vehicles

Who said CO2's the problem or do you just believe everything the
news
media says ?


Come on Graham,
Daniel went to great length to shows you results of a list of studies
on ALL
kind of pollutants. Not just CO2.
So why you pick out this one ?

Well *I* didn't. You want SO2, NOx, CxHx, particulates or what. Might
be best to
state that first.

I wonder if you even read the rest of Daniel's post (after you noticed
the letters CO2 reduction in the first lines).
Hint : ALL pollutants are down when we use grid electricity to drive
vehicles.

Sure. Light, aerodynamic vehicles that don't go very far will in fact
reduce pollution.

Right, but that's not what was stated in the studies.

What was stated is that vehicles driven from grid electricity pollute
significantly less that similar vehicles driven from gasoline or diesel.

John

 

[christofire]

"Mr. INTJ" <mr.intj@gmail.com> wrote in message
news:f4d5ac03-925b-4065-ab62-bd12d1bcac27@j1g2000prb.googlegroups.com...

Hi,

I have a problem - our dog has developed a phobia of smoke alarm
beeps. She's always been afraid during thunderstorms, but this smoke
detector thing is a whole new level of abject terror for her. It's
gotten to the point where if one of them even pips briefly (due to low
battery), she trembles all over, and tries to burrow under furniture
(usually at some ungodly hour of the morning).

OK, so I did what any responsible adult would do... I disconnected
every single smoke detector in the house. It was only supposed to be
short-term, but behavior mod. on our dog was $$$ and ineffective, and
after several months, I still don't have a solution.

MORE INFO:

Not all beeps are created equal - only certain combinations of
frequency, amplitude (and possibly waveform) strike terror in her. I'm
a software guy by trade, but I play an EE in my spare time, so when
this first started happening, I opened one of the smoke detectors and
examined it - hoping there'd be a simple R-C circuit that I could
modify in some way to alter things enough that it wouldn't freak out
the dog.

Of course there's a big piezo disc in there that's responsible for the
piercing beeps, and it was put together in such a way that I concluded
at the time that the pitch was tied to the physical dimensions of the
disc itself (a kind of mechanical buzzer), vs. the signal being
applied... does this sound possible, or was I sleep-deprived that day?

Can anyone shed more light on this?

Thanks.

Mr. INTJ
San Diego, CA

Such piezo sounders usually have the disc (metal disc with a layer of piezo
material covered with a layer of metallisation) mounted in a small closed
plastic cylinder with a hole which acts as a Helmholtz resonator.
Obviously, they're meant to sound loud and piercing because the hope is that
they'd wake you up when your house is on fire. If you're looking for
another sound that would be likely to do the same thing then I guess you'll
have to experiment with a range of alternative sounders - they can be
purchased from companies like CPC
(http://cpc.farnell.com/jsp/search/browse.jsp?N=411+1001780&Ns=PRICE_PLS_002_PRICE1%7C1)
and Maplin, in the UK, and equivalents in other countries. If you change
the frequency of the oscillator driving such a sounder, away from the
resonant frequency of the disc/cylinder combination then the sound level
will drop appreciably.
Good luck.

Chris