Author Topic: New Camera, "it's digital" (Read 17184 times)

12AX7 · « **Reply #33 on:** May 23, 2006, 09:44:37 PM »

Good Evening Oztules!

I'll take both.. pancakes and the "discription".

I'm a tad confused, about the pick up for the feed back.

Tell ya the truth, The "Gorlov" was pretty low on the "short list" of things to try.

(I bet stuff like that drives certain people nutz!)

But.. how about something along the lines of Windstuffs Vat?

Keep peace in the house!

oztules · « **Reply #34 on:** May 24, 2006, 04:24:10 AM »

Ok 12ax7

"I'm a tad confused, about the pick up for the feed back"... well...

On the right hand side the triangle is the speaker. R13 is the load resistor in series with the speaker coil, and so any activity in the transducer is reflected in the voltage across this resistor. This means the original drive signal, but also any backemf generated by the transducer.

By comparing the backemf to the input signal we can deduce an error signal, that can be fed back into the system and correct any anomolies that were being created by the speaker cone and it's resonant surroundings.

A copy of the input (what should happen signal) is fetched via R17 and fed to the + input of the U1B. A copy of the "what actually happened signal" from R13 is fed to the inverting input of U1B. These are compared and the resultant error signal is fed to the input amp U1A via the rc network through R8 into the inverting input, which corrects the input signal to allow for the errors found.

This all happens in real time, and so it can compensate for speaker location, resonance of the room, and poor speaker box design. I deliberatly built two boxes out of 1/8" plate steel with no damping inside, horn reflex... out of steel, just to give a terrible acoustic box... with this circuit, the bass was clean and clear, and the box sounded like a million bucks. Mid and treble were very lively, and no muddiness.

It is very useful learning device, particularly when used with the freq splitter, and three of these per channel..High,Mid and Low.

Hope this clears up some confusion.

Phillips had a MFB system back in the seventies, and they incorporated an accelorometer (microphone) and a fet amp built onto the cone itself to generate the "what actually happened" signal. It works well,but this system delivers the same result, without having to build a microphone and amplifier on every speaker you wish to use.

Some Sub woofers are apparently using some kind of MFB, but I don't know how they are doing it, microphone or backemf.

..............oztules

willib · « **Reply #35 on:** May 24, 2006, 08:17:06 AM »

ozzy , what would happen in the pwm circuit ,from before , if the input went negetive?

would it cause a catastrophic failure , or just no output?

i'm talking about using your boost circuit on a sine wave as input

willib · « **Reply #36 on:** May 24, 2006, 09:17:14 AM »

no output -- for the negative part of the wave i mean

oztules · « **Reply #37 on:** May 24, 2006, 03:55:59 PM »

Interesting Willib,

I've tried to kill fets in all sorts of ways (and been quite successful at it too), but not that way yet.

I assume the body diodes in the fets would conduct and short the coil for the full 1/2 cycle that was negative, and self immolate.

not having tried this i can't say for certain this will happen, but it is what i would expect.

Why would you be considering this?

You can use power inverters as amplifiers by modulating the drive signal to shape the pulse widths, but i can't see why you would want to try and use them as a half wave rectifier/booster...pile of ash type arrangement.

watchaupto willibi

..............oztules

willib · « **Reply #38 on:** May 24, 2006, 06:07:33 PM »

i hooked the output of my mini gen to a PWM circuit , no boost inductor..

the body diode did in fact conduct for the part of the wave that was negative

what i'm thinking about is synchronous rectification to try and eliminate the diode drop on my mini gen . the resulting wave was really interesting when i turned on the pwm

12AX7 · « **Reply #39 on:** May 24, 2006, 09:47:34 PM »

Evening Oztules!

Yes it does! clears up some, but like they say... one door closes and another opens.

Steel plates for speaker cabinets?

wow..

they cut down all the trees on your island?

I've never had a chance to listen to a million bucks. Heard two or three snorting in the woods. (I think they coulda been fartin).. dang, come to think of it.. never seen a million bucks.

Sounds like you've had your hands in LOTS of SSstuff. Ever do any tweaking on cd or dvd players?

Back in the seventies I was showing others how a 20 year old "The Fisher" (22 wrms or so) could blow the doors off of Flamming Linear 400 [with in certain SPLs]

So if I can VERY quickly read into this.. the circuit should be ideal for FB for a voice coil motor!

and Speaking of.. OTHER type of uses.. sure looks like someone else has something completely different!

We're gonna keep you jumping!

willib · « **Reply #40 on:** May 25, 2006, 09:59:54 PM »

oz , what are you up to?

did you get the stuff for your wind turbine yet?

or are you in the lab?

poke your head out , and spill !

i could take a picture of the waveform i would just have to reassemble the minigen

oztules · « **Reply #41 on:** May 25, 2006, 10:24:44 PM »

Willib, no stuff for the turbine yet I'm afraid.

I'm currently building a new possum - proof and kangaroo proof veggie garden for the missus.

Lab will have to be night work at the moment (and it's cold out at night in the shed and I'm a bit of a sook.)

My son flew in from the mainland and will be here for a few weeks. (have to keep him entertained I guess)

Do take a pic of the wave form and a scribble circuit. I'm at a loss what your up to.

If you want synchronous rectification, I'm not sure this will achieve it, but I'll wait and see what you have.

I would expect to use the fets as 1/2 wave switches in place of the diodes, and make a switching circuit to achieve the switch on and off at near zero voltage. It won't matter if it doesn't turn on till later in the cycle as we only need the tops of the wave, rectifying the first and last part of the sine, will not make any difference as they will be below battery voltage, and so won't usefully contribute anyway.

The battery should be used for the gate drive voltage.

If you are boosting, then you wont need the synchronous rectification complication as the voltage drop over the diode will be compensated for by the booster anyway..... although some small improvement in rectification efficiency should be available.

In the current climate, this sort of thread jacking is frowned upon, although 12ax7 may well need synchronous rectification on his water wheel.. in which case he will be happy.

You may need to start a new thread for this one... could be a biggie.

...................oztules

willib · « **Reply #42 on:** May 26, 2006, 12:03:16 AM »

12AX7 i hope you dont mind

it is just that this thread seemd like the oz home for the present time.

and rather than start a new thread to see what oz was up to i started posting here,if you mind just say so

oz , let me discribe the circuit, i have the scope attached across the FET( pwm ),

the input to the circuit is the output of one phase of mini gen, the load is a 1157 taillight bulb

i think what is going on is the coils in the gen are acting as the boost inductor in your circuit, but i'm not sure

it certainly is different !

willib · « **Reply #43 on:** May 26, 2006, 12:25:16 AM »

12AX7 how about a succession of paddle wheels , one in front of the other all linked by chain , tough yes but not impossible , and hooked together so any or all can contribute to the final output , but not detract from it.

a bicycle rear sprocket assembly can accomplish this , the coaster brake ..

that way when one is going slower than the rest it wont slow down the whole works

oztules · « **Reply #44 on:** May 26, 2006, 02:14:45 AM »

well well well,

it looks like youre trying to make a true sinewave inverter from a calculus inspired waveform.

I assume the second half of the wave is flat as it is short curcuit on the neg waveform from the body diode.

It appears to be acting as a boost converter on this half of the wave.

I think if you look at " Matching the load", you will see flux has described this type of device (after rectification) on iron cored alternators. It looks like some degree of boost can be obtained from the axial flux without the iron component.

It was Jimovnz using aircores on his boost device as well from memory. Perhaps he has run into this already.

interesting stuff...

Rather than synchronous rectification with all of its problems, just rectify as usual and boost using the alternator as the coil, the 1/2 volt you lose with the diode will be easily taken care of by the boost.

With no power inductor needed, it will make for a very tiny boost converter. I have just finished building one with with a single ended pwm chip...L4990. It has a fet driver built in. Haven't tested it yet, will do a short diary of it soon. It may be ideal for this application.

................oztules

willib · « **Reply #45 on:** May 26, 2006, 06:17:32 AM »

yes its flat

here i've slowed the sweep rate

12AX7 · « **Reply #46 on:** May 26, 2006, 08:52:32 AM »

Morning Oztules!

Don't worry about any jacking of threads of mine!

Hey Willb.. same goes for you!

fungus · « **Reply #47 on:** May 26, 2006, 12:22:19 PM »

In Britain junk yard wars is called scrapheap challenge.

willib · « **Reply #48 on:** May 26, 2006, 07:35:36 PM »

from the data sheet...

"Duty Cycle Control

Duty Cycle DC is externally programmed by setting

a voltage between 1V (0% DC) and 3V

(100% DC) at the DC pin. The programmed voltage

is compared with the oscillator CT capacitor

charging waveform to determine the maximum

ON-time in each period. This function gives a fine

control of DC.

If this pin is floating the maximum duty cycle depends

on DC-LIM status."

so you have yourself a varible pwm

nice!

i tried to find where flux mentioned using the coils in the alt for boost , but alas i could not find it , if you have that particular post could you maybe point it out to me

oztules · « **Reply #49 on:** May 26, 2006, 08:49:28 PM »

http://www.fieldlines.com/comments/2006/3/17/185646/194/35 should do it.

The pwm width can be controlled from either two error amps . It's max width is set from the duty cylce control. Could be handy to shape a modified sine converter.

.........oztules

willib · « **Reply #50 on:** May 26, 2006, 09:26:37 PM »

ehh it was worth a try .

maybe my lil' mini gen just isnt outputting enough voltage , or maybe i just need a stronger fan.

its produceing 2V dc with the fan on high , it does humm with a high pitch though when i put the pwm on it.

12AX7 · « **Reply #51 on:** April 17, 2010, 10:17:51 PM »

Just trying to upload a pic to the new board

nope, guess I'll have to figure how to re size them.

12AX7 · « **Reply #52 on:** April 18, 2010, 12:19:01 AM »

Well, my fist re-sizing was a failure. I used ms paint to re-size and the thumb nails look okay, but once up loaded only the upper left quarter shows up.

second try used ms office picture editor.

here goes...

should see a white 55 gal barrel in the river.

HOT dang! I think it worked!
Might not be easy to see but the barrel has both the top and bottom cut out. Gives the idea of depth and current.
I wonder if an underwater VAWT would work.
These pics show the river at slightly above it's summer Lowest level. Depending on the rain and snow numbers the level has reached to several inches below the wall (about three feet higher/deeper than shown).

by the way... I think I like the new board/system. just gotta teach this old dog new tricks, and I KNOW I like the "modify" feature.

fabricator · « **Reply #53 on:** April 23, 2010, 08:35:15 PM »

I would kill to have a hydro asset like that.

12AX7 · « **Reply #54 on:** April 23, 2010, 08:54:45 PM »

Hello Fabicator

It's been a long time since I've suggested a hydro setup at this location. Most suggested that with out 'head' or 'drop' power recovery from this location was all but hopeless.

I've stood where the barrel is located (in the summer when the water is much warmer) and held a coal shovel in the current, there's plenty of energy there. It's not possible to dam up the river but that doesn't mean I can't "play" in the river and move some rocks around.

I had planned on building a floating paddle wheel, but since then have had second thoughts. Most due to safety issues.
This river is a nice trout stream, and my yard is a prime area to fish from. Lots of people wander here to fish, and I wouldn't want to stop them. The thought of a kid and a large paddle wheel sounds like a BAD thing.

I've seen a few online videos of a "spiral screw" type turbine.
Any opinions?

ax7
Mark

fabricator · « **Reply #55 on:** April 23, 2010, 09:34:44 PM »

It sure seems like there ought to be something, how much frontage do you own on the stream?

12AX7 · « **Reply #56 on:** April 23, 2010, 11:23:52 PM »

Hello!

We have about 300 ft of river frontage.

The place where the picture is taken is the most narrow point.
The wall that is shown is what's left of an old (removed a long long time ago) Rail Road Trestle. I've not measured, but I'm guessing it's about 30 ft. wide.

Over the 300 ft. stretch there is very little drop/head.
As I said, I can't find my picture file, where ever it is.. there are pics showing the location from several different points of view. Those same pics show the river at about it's lowest level. It may stay low for a few months (Aug and Sept) then rise to about the level shown in the has few pics I've posted here.

Most of our frontage is "up river" from the shown location. At the back of our property the river widens to about 80ft, and the depth is not much more than a foot (low level).

I suppose I could "drop in" a V type funnel to force more water to the "sweet spot"
I'd have to do it with a pile of rocks under water, But I have to leave a place for canoes and kayaks to pass by.

I'd think the only way I could get away with this is... by "PLAYING" in the river with my grandkids. *L*

At high water (flooding conditions) the point shown is five/six feet deep and the current very dangerous.

There's LOTs of Power there!
On the down side, I'm in Wisconsin, and this river will freeze over for three/four months. (but it still flows under the ice).

ax7
Mark

wooferhound · « **Reply #57 on:** April 24, 2010, 09:25:51 AM »

Hey !2AX7

Here are your Files . . .
http://www.otherpower.com/images/scimages/4822

12AX7 · « **Reply #58 on:** May 09, 2010, 01:02:08 AM »

Any opinions of a VAHT in the location of the white plastic 55 gallon barrel?

As shown, the location is near shore, and less than 100 ft. to my house.
My initial thoughts is to use a ac servo motor that I've salvaged from the junk pile.
I'll have to dig out it's specs again, it's been sitting on a back shelf for close to three years.
(pictures are/were in my files).

ax7
Mark

12AX7 · « **Reply #59 on:** January 31, 2012, 08:46:20 PM »

just checking to see if this thread still works.

12AX7 · « **Reply #60 on:** February 01, 2012, 10:30:55 PM »

Well, I guess it still works!

and browsing thru it I wonder, what ever happened to Nando?

RP · « **Reply #61 on:** February 02, 2012, 08:44:32 PM »

Yep, Still works!

As I recall Nando got into a pissing match with someone(s) and quit the forum a few years back. A google search here:

http://www.google.com/#hl=en&safe=off&q=nando+hydro&oq=nando+hydro&aq=f&aqi=&aql=&gs_sm=e&gs_upl=6225l9276l0l9812l6l6l0l0l0l0l121l623l3.3l6l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=3862cd7193b9ee29&biw=1095&bih=768

indicates he is still active on a yahoo hydro forum. FWIW, the first link indicates he is still getting into pissing matches too...

JW · « **Reply #62 on:** February 02, 2012, 09:24:48 PM »

Well thats just fantastic...

Why is Nando so relevent here, according to the topic. There's been a few users over the years who were treated unfairly (I was a lurker at the time)

On a simular note, I was happy to accomodate Dinges, and help him get his "original" account back up and running for him...

It makes sense Woof would be able to find the search criteria here.

JW

12AX7 · « **Reply #63 on:** February 02, 2012, 10:14:27 PM »

Quote from: JW on February 02, 2012, 09:24:48 PM

Well thats just fantastic...

Why is Nando so relevent here, according to the topic. There's been a few users over the years who were treated unfairly (I was a lurker at the time)

On a simular note, I was happy to accomodate Dinges, and help him get his "original" account back up and running for him...

It makes sense Woof would be able to find the search criteria here.

JW

Okay, I've read this post several times and I'm still confused.

What's fantastic?

Why is Nando so relevant Where? This forum, this thread (mine) or at the Yahoo site or else where?

What search criteria was Woofer looking for, and why/what did he find here?

What about Dingles? and similar to what and how?

Is there some relationship between Nando and Dingles?

Sorry, I'm just confused!

Bruce S · « **Reply #64 on:** February 03, 2012, 01:22:23 AM »

JW:
NANDO is very relevant here since he and a few other long time posters were on this original thread.
GREAT people not just Nando, but Zubbly (RIP) N.T.L. (Fellow Missouri boy) who sold #29 special style Neos back in the day.
This thread goes back 5+ years, plus it was originally about pics from a new camera and one of the orignial posters asked about Nando.
Nando handed him some very sage advice.

Bruce S

JW · « **Reply #65 on:** February 03, 2012, 08:43:06 AM »

Thanks Bruce,

I was around when Nando was here, all I remember was that he had a hardtime.

12AX7 the thing about Dinges is just what I said, I helped him recover his original account and he's posting again.

The sage advise thing is probably why he had a hardtime, nobody is perfect. Danb still talks to Nando.

I will try to be less confusing.

JW

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Author Topic: New Camera, "it's digital" (Read 17184 times)