Stef expounded in news:5e09b$4c767894$54f63171$3844@abuse.newsxs.nl:

> In comp.arch.embedded,
> Warren <ve3wwg@gmail.com> wrote:
>> D Yuniskis expounded in news:i53bvq$sbs$1@speranza.aioe.org:
>>
>>> Warren wrote:
>>>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>>>> @v41g2000yqv.googlegroups.com:
>>>> 
>>>>> Does anyone have any ideas for an embedded renewable/energy related
>>>>> project? ..
>>>> 
>>>> One idea I've had, would be to use a MCU to control the
>>>> input to an automotive alternator, used in a wind generator. 
>>>> When the wind dies down below a threshold, you want to cut the 
>>>> rotor input power, since you're not going to get anything back.
>>>> When it picks up, apply some input power to help it "generate".
>>> 
>>> I wonder if you could watch the field in the windings to
>>> detect RPM (without having to add a tacho).  
>>
>> Even though the alternator rectifies the current, it is
>> not pure DC. So the charging current will look like a
>> series of bumps. Feed that into a opamp circuit and 
>> shape that into something a MCU can count.
>>
>> This is the "whine" component of the alternator.  At 
>> least this is how I would attack it, as it requires
>> no addional parts for monitoring (rpm).
> 
> Most alternators hav a 'W' contact. This is connected to the AC
> side of the rectifier, giving you a higer amplitude rpm signal.

"W" for "whine". ;-)

Warren

In comp.arch.embedded,
Warren <ve3wwg@gmail.com> wrote:
> Stef expounded in news:b1298$4c73dd0d$54f63171$5945@abuse.newsxs.nl:
>
>> In comp.arch.embedded,
>> Warren <ve3wwg@gmail.com> wrote:
>>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>>> @v41g2000yqv.googlegroups.com:
>>>
>>>> Does anyone have any ideas for an embedded renewable/energy related
>>>> project? I want to do something at home so I can put it on my resume
>>>> and try to enter this field, after a LONG hiatus. Type away with
>>>> what you got. I thought it would be good for me to include these
>>>> aspects: - wireless communications
>>>> - data gets sent to a website
>>>> - SMS messaging
>>>> Yea, stuff like that. If you've had any ideas relating to renewable-
>>>> energy related embedded projects, please share them. Thankyou!
>>>
>>> One idea I've had, would be to use a MCU to control the
>>> input to an automotive alternator, used in a wind generator. 
>>> When the wind dies down below a threshold, you want to cut the 
>>> rotor input power, since you're not going to get anything back.
>>> When it picks up, apply some input power to help it "generate".
>>>
>>> Beyond the threshold test, the MCU could adjust input power levels to
>>> the rotor to maximize the output generation. If the wind is weak,
>>> then you need to supply less of a field. But to get more out of a
>>> strong wind, you could add more rotor input power.
>>>
>> To avoid this hassle, wind turbines often use permanent magnet rotors.
>> :-) It's also more power efficient (no exictation) and less wear (no
>> brushes) Car alternators can be modified to permanent magnet.
>
> The MCU makes it a non-hassle ;-)  The downside is the
> brushes naturally, but the upside is that you can
> vary power output with the strength of the wind.  IIRC,
> you can get up to 60 Amps from a little alternator, perhaps
> more with some models, though probably not continously.
>
> The trick is to monitor the rpm and not to exceed
> maximum continous ratings. If you increase the field,
> does output continue to increase (while maintaining rpm),
> or does it tend towards stalling? If it tends to stall,
> you back off the field and acheive a compromise for
> maximum generated power.
>
> Putting a permanent magnet in, just destroys all the fun!

No, no, it just starts the fun! (law of preservation of hassle :-)

Using a permanent magnet means you have no control over the
alternator output. So now you should add a controller that regulates
the power take off to maintain optimum power point and does not
destroy your battery!

Oh, and don't forget to add a braking mechanism, otherwise your
turbine will spin out of control on strong winds and light loads
(battery full for example).


-- 
Stef    (remove caps, dashes and .invalid from e-mail address to reply by mail)

My pants just went to high school in the Carlsbad Caverns!!!

In comp.arch.embedded,
Warren <ve3wwg@gmail.com> wrote:
> D Yuniskis expounded in news:i53bvq$sbs$1@speranza.aioe.org:
>
>> Warren wrote:
>>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>>> @v41g2000yqv.googlegroups.com:
>>> 
>>>> Does anyone have any ideas for an embedded renewable/energy related
>>>> project? ..
>>> 
>>> One idea I've had, would be to use a MCU to control the
>>> input to an automotive alternator, used in a wind generator. 
>>> When the wind dies down below a threshold, you want to cut the 
>>> rotor input power, since you're not going to get anything back.
>>> When it picks up, apply some input power to help it "generate".
>> 
>> I wonder if you could watch the field in the windings to
>> detect RPM (without having to add a tacho).  
>
> Even though the alternator rectifies the current, it is
> not pure DC. So the charging current will look like a
> series of bumps. Feed that into a opamp circuit and 
> shape that into something a MCU can count.
>
> This is the "whine" component of the alternator.  At 
> least this is how I would attack it, as it requires
> no addional parts for monitoring (rpm).

Most alternators hav a 'W' contact. This is connected to the AC
side of the rectifier, giving you a higer amplitude rpm signal.


-- 
Stef    (remove caps, dashes and .invalid from e-mail address to reply by mail)

linux: because a PC is a terrible thing to waste
(ksh@cis.ufl.edu put this on Tshirts in '93)

D Yuniskis expounded in news:i53bvq$sbs$1@speranza.aioe.org:

> Warren wrote:
>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>> @v41g2000yqv.googlegroups.com:
>> 
>>> Does anyone have any ideas for an embedded renewable/energy related
>>> project? ..
>> 
>> One idea I've had, would be to use a MCU to control the
>> input to an automotive alternator, used in a wind generator. 
>> When the wind dies down below a threshold, you want to cut the 
>> rotor input power, since you're not going to get anything back.
>> When it picks up, apply some input power to help it "generate".
> 
> I wonder if you could watch the field in the windings to
> detect RPM (without having to add a tacho).  

Even though the alternator rectifies the current, it is
not pure DC. So the charging current will look like a
series of bumps. Feed that into a opamp circuit and 
shape that into something a MCU can count.

This is the "whine" component of the alternator.  At 
least this is how I would attack it, as it requires
no addional parts for monitoring (rpm).

> Use that as
> a "wind sensor" (instead of watching the actual output
> of the alternator).  

I think there are many smaller lighter components
that would better serve as a sensor. You could
probably make one out of an old fashioned (ball)
mouse, that has those optical encoder wheels in them.
Attach that to a tiny plastic fan.

>> Now of course you need to store that "juice" in batteries, and having
>> your alternator generating peak output will probably be bad for your 
>> battery(ies) if they're fully charged already. So some sort of
>> battery management would also be required.
> 
> I think a more realistic project might be a controller to
> dynamically fit a (charger) load to the output of a solar
> panel.  This is "existing technology" yet shows a variety
> of issues that have to be addressed in the design of the
> hardware and software to do so economically and reliably.

Related to this idea, I have another rolling around
in the back of my mind:

- Provide "load tests" and measure batter performance on
  loads over time (until they are exhausted).

- Feed results into a PC (or memory stick), for later
  performance analysis.

The idea is to test various brands of batteries under "load".
A simple voltage test is a "no load" test (the volt meter is
virtually no load at all).

Then you could plot "bang for your buck" charts for batteries
by brand and price.  Then you can answer questions like:

If I spend extra on the "copper top" am I getting more
than if I go cheap on some "no name" brand, which I know
will run out sooner?

I'd also perform these tests on a light vs heavy load
basis, so you can answer the right question for the
right application. Presmably the bang for the buck would
be similar, but the test would answer the question 
"are they the same?"

Light loads might be for electronic toys, calculators etc.
while the heavy load performance is important to toy cars
etc., that tend to eat batteries.

For load testing, you need a power transistor activated
by the MCU periodically. Turn on the one with the appropriate
load resistance attached.

After this, you could publish your findings 
for the rest of us. ;-)

Warren

Stef expounded in news:b1298$4c73dd0d$54f63171$5945@abuse.newsxs.nl:

> In comp.arch.embedded,
> Warren <ve3wwg@gmail.com> wrote:
>> Alex expounded in news:4d220f9d-0536-46e5-8265-e2e28b2fba50
>> @v41g2000yqv.googlegroups.com:
>>
>>> Does anyone have any ideas for an embedded renewable/energy related
>>> project? I want to do something at home so I can put it on my resume
>>> and try to enter this field, after a LONG hiatus. Type away with
>>> what you got. I thought it would be good for me to include these
>>> aspects: - wireless communications
>>> - data gets sent to a website
>>> - SMS messaging
>>> Yea, stuff like that. If you've had any ideas relating to renewable-
>>> energy related embedded projects, please share them. Thankyou!
>>
>> One idea I've had, would be to use a MCU to control the
>> input to an automotive alternator, used in a wind generator. 
>> When the wind dies down below a threshold, you want to cut the 
>> rotor input power, since you're not going to get anything back.
>> When it picks up, apply some input power to help it "generate".
>>
>> Beyond the threshold test, the MCU could adjust input power levels to
>> the rotor to maximize the output generation. If the wind is weak,
>> then you need to supply less of a field. But to get more out of a
>> strong wind, you could add more rotor input power.
>>
> To avoid this hassle, wind turbines often use permanent magnet rotors.
> :-) It's also more power efficient (no exictation) and less wear (no
> brushes) Car alternators can be modified to permanent magnet.

The MCU makes it a non-hassle ;-)  The downside is the
brushes naturally, but the upside is that you can
vary power output with the strength of the wind.  IIRC,
you can get up to 60 Amps from a little alternator, perhaps
more with some models, though probably not continously.

The trick is to monitor the rpm and not to exceed
maximum continous ratings. If you increase the field,
does output continue to increase (while maintaining rpm),
or does it tend towards stalling? If it tends to stall,
you back off the field and acheive a compromise for
maximum generated power.

Putting a permanent magnet in, just destroys all the fun!

Warren

Hi Paul,

Paul Keinanen wrote:
> On Tue, 24 Aug 2010 10:05:15 -0700, Jim Stewart <jstewart@jkmicro.com>
> wrote:
> 
>> I'd like an intelligent lawn watering system.
>>
>> Something that would sense soil moisture content,
>> ambient temperature and humidity, and the presence
>> of a car in the driveway and then adjust sprinkler on
>> time and duration appropriately.
> 
> I hope the system is intelligent enough to turn the water off during
> the day and only operate during the night.
> 
> When using a sprinkler during a hot day with low relative humidity,
> will evaporate some of the water before it hits the ground.

Here (desert southwest), the evaporative losses from classic
"sprinklers" are touted as *40%*!

> During the night, the water will actually penetrate the ground (and
> not evaporate directly from the ground) and actually reach the roots
> of the grass.

On Tue, 24 Aug 2010 10:05:15 -0700, Jim Stewart <jstewart@jkmicro.com>
wrote:

>
>I'd like an intelligent lawn watering system.
>
>Something that would sense soil moisture content,
>ambient temperature and humidity, and the presence
>of a car in the driveway and then adjust sprinkler on
>time and duration appropriately.

I hope the system is intelligent enough to turn the water off during
the day and only operate during the night.

When using a sprinkler during a hot day with low relative humidity,
will evaporate some of the water before it hits the ground.

During the night, the water will actually penetrate the ground (and
not evaporate directly from the ground) and actually reach the roots
of the grass.

linnix wrote:
>>> Better yet, detect if the guy in the car is a traveling salesman, or
>>> "the other man" and if so, turn the sprinkler on just as he gets out...
>> I think a better approach is to design a system that washes
>> the car when it determines the lawn is in need of watering...
> 
> I thought about that.
> 
> But then I would have to move the car to the lawn.  Moving in is easy;
> Moving out would be tough with wet soil.  Assuming that the wheels
> won't kill the lawn in the first place.
> 
> I can rebuild my drive way to catch and redirect the water.
> 
> Or I can build a lift to move the car between the lawn and driveway.
> 
> Nevermind, too much work to save some water.

(sigh)  Sorry, I guess my humor was missed
(think: "it always rains just after you wash your car...")

On Aug 25, 8:45=A0am, D Yuniskis <not.going.to...@seen.com> wrote:
> Tim Wescott wrote:
> > On 08/24/2010 10:05 AM, Jim Stewart wrote:
> >> Tim Wescott wrote:
> >>> My inner Diogenes wants to say that any manager who's ditzy enough to
> >>> think that working on some random "green" project is going to qualify
> >>> you to work on his _specific_ "green" project is a manager who's too
> >>> ditzy for me.
>
> >>> But maybe you have to get your resume through HR first, or you just w=
ant
> >>> to do a "green" project.
>
> >>> Isn't there any product you've always wanted, but never had?
>
> >>> I'd like a programmable house fan that comes on whenever the inside o=
f
> >>> my house is farther away from some target temperature than the outsid=
e
> >>> of the house, to provide mostly-passive climate control. Basically it
> >>> would be something that mechanizes "open the windows tonight, dear, a=
nd
> >>> we won't have to run the air conditioner tomorrow".
>
> >>> I think they're made already, but there's little that you could do
> >>> that's not made already, so you can't let that be a barrier.
>
> But, you can do many of these things *better* (or, at least,
> *differently*!)
>
> >> I'd like an intelligent lawn watering system.
>
> >> Something that would sense soil moisture content,
> >> ambient temperature and humidity, and the presence
> >> of a car in the driveway and then adjust sprinkler on
> >> time and duration appropriately.
>
> > Better yet, detect if the guy in the car is a traveling salesman, or
> > "the other man" and if so, turn the sprinkler on just as he gets out...
>
> I think a better approach is to design a system that washes
> the car when it determines the lawn is in need of watering...

I thought about that.

But then I would have to move the car to the lawn.  Moving in is easy;
Moving out would be tough with wet soil.  Assuming that the wheels
won't kill the lawn in the first place.

I can rebuild my drive way to catch and redirect the water.

Or I can build a lift to move the car between the lawn and driveway.

Nevermind, too much work to save some water.

Tim Wescott wrote:
> On 08/24/2010 10:05 AM, Jim Stewart wrote:
>> Tim Wescott wrote:
>>> My inner Diogenes wants to say that any manager who's ditzy enough to
>>> think that working on some random "green" project is going to qualify
>>> you to work on his _specific_ "green" project is a manager who's too
>>> ditzy for me.
>>>
>>> But maybe you have to get your resume through HR first, or you just want
>>> to do a "green" project.
>>>
>>> Isn't there any product you've always wanted, but never had?
>>>
>>> I'd like a programmable house fan that comes on whenever the inside of
>>> my house is farther away from some target temperature than the outside
>>> of the house, to provide mostly-passive climate control. Basically it
>>> would be something that mechanizes "open the windows tonight, dear, and
>>> we won't have to run the air conditioner tomorrow".
>>>
>>> I think they're made already, but there's little that you could do
>>> that's not made already, so you can't let that be a barrier.

But, you can do many of these things *better* (or, at least,
*differently*!)

>> I'd like an intelligent lawn watering system.
>>
>> Something that would sense soil moisture content,
>> ambient temperature and humidity, and the presence
>> of a car in the driveway and then adjust sprinkler on
>> time and duration appropriately.
> 
> Better yet, detect if the guy in the car is a traveling salesman, or 
> "the other man" and if so, turn the sprinkler on just as he gets out...

I think a better approach is to design a system that washes
the car when it determines the lawn is in need of watering...