HDTenEightyP/NetNews huggingface dataset:
From: gkwan@balboa.eng.uci.edu (Greg Kwan)
Subject: Re: Detecting muscle voltages
Newsgroups: sci.electronics
Organization: University of California, Irvine
Date: 17 Apr 92 02:23:48 GMT

In article <1992Apr16.174641.25906@intelhf.hf.intel.com> dcovell@pcocd2.intel.com (David Covell) writes:
>I'm interested in experimenting with the detection and digitizing of the
>voltages involved with human muscle activity. I intend to use the electrodes
>they use for EEG testing, placing them over certain facial muscles.
>I don't know what sort of voltages I'll see, but I assume they'll be quite
>low and I'll need to use a low-noise op amp before I do my A/D conversion.
>Anyone out there have a good estimate of the levels I'll see?

For my senior design project ("A Myoelectrically Controlled Prosthetic
Arm"), I observed surface EMG signals with typical ranges of ~3 uV to 1mV
and ~20Hz to 1.5kHz.  Of course these were generated from the biceps and
triceps and would therefore be larger in amplitude than facial muscles.  I
also used silver-silver chloride electrodes (disposable surface types com-
monly used with ECG machines). You'll need to use a good instrumentation
amp with filtering and rectification to get workable signal levels.

Books to look into: 
_Design of Microcomputer-Based Medical Instrumentation_, edited by John
Webster and Willis J. Tompkins, Prentice-Hall, Inc., 1978.

_Medical Instrumentation: Application and Design_, edited by John Webster,
Houghton Mifflin Company, 1981.

_Electromyography for Experimentalists_, by Gerald E. Loeb and C. Gans, The
University of Chicago Press, 1986.


don't shock yourself.
greg

gkwan@balboa.eng.uci.edu
Newsgroups: sci.electronics
From: louis@tronix.SignalPath.on.ca (Louis Bertrand)
Subject: Re: Jacob's Ladder
Newsgroups: sci.electronics
Date: 12 Apr 92 03:03:19 GMT
Distribution: world
Organization: Signal Path Designs

Another cheap source of high voltage is oil furnace ignition
transformers.  They are getting rare, but the old ones kicked
out 25KV.  If you're really lucky, you can get one for 25Hz
operation, but then, you'd have to build your own 25Hz generating
station...
 -- Louis
--
Louis Bertrand   *   Lynden, Ontario, Canada   *   (416) 648-8066
Signal Path Designs (Analog - Digital - Audio - Embedded uCs)
louis@SignalPath.on.ca (new -- may not work yet)
louis%tronix@maccs.dcss.mcmaster.ca (old -- still works fine)
From: rg@kunikpok.UUCP (r.g.)
Newsgroups: sci.electronics
Subject: radar traps
Date: Wed, 08 Apr 92 22:26:47 CDT
Organization: Kunikpok Kennels & Komputers

There is a book I saw once in Car and Driver about beating speeding 
tickets in court. Not much help, I can't remember the name. 

The best thing to do is to go to court. I took my last ticket to court
and had the case dismissed. Have a very clear story ready, detailing 
the situation as you see it, with all of the possible questions ready
about why you think the police were in error. If you just show up in 
court, you have a 5 to 7 in 10 chance that the officer will not show
up to testify, at least in my home town; these cases are dismissed out of
hand. The remainder are encouraged to plea bargain with the prosecutor.
You may very well make a reasonable deal there. 

If you do this, make your best showing. Show up on time, look as 
professional and businesslike as possible (most of the people were there
in jeans - I was in a suit), have the mind set that you will be polite, 
unruffled and firm. You must be prepared to see this through if you do it.

If you are one of the minority actually to be tried, you may well have court 
costs added to your fine, so there is a down side, too.

It was my own turn in court that convinced me that the majority of tickets
are actually issued to people violating the law as written - but that the 
courts are completely unprepared to cope with the sheer numbers of cases
if every violator was brought to trial. The only reason the traffic 
enforcement system works at all is that most people pay up without making
a fuss. This has made traffic enforcement into a revenue system.

Philosophically, this is doubleplusungood. I don't want to live in a 
society where this kind of thing happens for all crimes. But I also 
don't like the tickets.

Go to court.

R.G.
From: beyo@beyonet.UUCP (Steve Urich)
Newsgroups: sci.electronics
Subject: Re: HV shocks (was: Jacob's ladder)
Date: 15 Apr 92 23:17:43 GMT
Organization: Beyonet Network

jgd@dixie.com (John De Armond) writes:
[...]
>Yeah.  You and I both.  You'd have loved our electric chair I built when
>I was a yound teenager. 
[...]
>A bit of teenage hormonal thinking resulted in it being turned into
>a test of manhood. 
[...]
>Yep, amazing we made it to adulthood.  Makes me chuckle when I 
>think about the risk-sterile society some would now force on us.

	Thats pretty funny, I remember the time I lived over in germany.
	I was about 13years old and was strolling the countryside with
	my american huffy and the monkey bars with the bannana seat :-).
	We live in Bavaria in the country. I met a group of german kids
	playing a game with the electric fence the farmers used to keep
	the cows inside there grazing land. It wasn't how high of a voltage
	you could withstand but how long you could hold on to the 
	electric fence. I was pretty funny you could see the jerking
	movements of the body every second or so. It seemed the generator
	was producing intermittant dc or ac. I tried it and believe me
	at that age it didn't feel too cool. :-).

Steve
-- 
 ############### Stephen Urich WB3FTP |"Starlightbeams project ###############
 ##|_|########## Bensalem, PA  USA    |me in Red Blue and Green##|_|##########
 ###############----------------------|Velvetdreams protect me ###############
 ####       #### snark!beyonet!beyo   |when I hit the Screen"  ####       ####
 ##    |_|    ## widener!beyonet!beyo |--Alan Parsons Project  ##    |_|    ##
 ##           ##-----------------------------------------------##           ##
 ####       ####  Packet Radio: WB3FTP@WA3NWL.#SEPA.PA.USA.NA  ####       ####
_###############_______________________________________________###############_
Newsgroups: sci.electronics
From: pschleck@odin.unomaha.edu (Paul W Schleck KD3FU)
Subject: Chirping Chick Toy, interesting novelty...
Organization: University of Nebraska at Omaha
Date: Fri, 10 Apr 1992 16:53:19 GMT

I was wandering through Walgreen's drug the other day, and saw an
interesting Easter toy selling for a couple of bucks.  It's a
fuzzy chick that chirps when you hold it in the palm of your hand.
The woman behind the register was kind enough to demonstrate it for
me.  Touching two metal grommets on the bottom of the thing started
it chirping.

Since skin has a very high impedance (i.e. when you touch two
probes of a multimeter to your hand, you don't get a measurable
amount of resistance/load), it probably detects the very slight
difference between an infinite resistance/impedance, and the very high 
impedance of skin (warm, oily/sweaty skin works better than cold/dry
skin, fingertips work better than the palm of your hand, etc., etc.).

Shorting the contacts with metal like copper produces unpredictable
results (fast, irregular chirping, or no chirping at all) probably
due to it being sensitive to too much load.

I only have one of them right now (and it is already reserved as
a present), but when I get some more (hey, if you can get over
the embarrassment of buying SOME things at a drugstore, you can
buy ANYTHING :-), I'll sacrifice one to science and report on its
"guts".  It uses a standard watch battery and might be an interesting/
educational present for the little tykes.

Paul W. Schleck, KD3FU

pschleck@odin.unomaha.edu
From: rdi@cci632.cci.com (Rick Inzero)
Newsgroups: sci.electronics
Subject: Re: Jacob's Ladder
Summary: This was a TEST!
Date: 15 Apr 92 17:00:28 GMT
Reply-To: rdi@ccird3.UUCP (Rick Inzero)
Distribution: na
Organization: CCI, Communications Systems Division, Rochester, NY

In article <1992Apr13.093036.425@cmkrnl.com> jeh@cmkrnl.com writes:
>In article <1992Apr8.161347.3926@ole.uucp>, ray@ole.uucp (Ray Berry) writes:
>> rdi@cci632.cci.com (Rick Inzero) writes:
>> ...
>>>Note that there exist some big neon sign transformers.  Mine
>>>is rated 15,000 volts at *3000* ma.  This most certainly would
>>           ^^^^^^^^^^^^^^^^^^^^^^^^^^
>> 	Must be a real honker- 15 KV * 3 A = 45 KVA :-).. Pray tell, how many
>> hundreds of pounds does it way [sic], and for what purpose was it designed?  Curious
>> minds...
>
>For that matter, what do you power it with?  That's more power than an entire
>house is typically supplied with (residential 100-amp service). 45 KVA would
>eat 125 A from *all three phases* of 120/208 "wye" three-phase.  
>

I take 5 or 6 lengths of 2 gauge wire, and climb up the
pole around midnight, and hook 'er up!  The spark jumps
between the aluminum siding on my neighbor's house, and
mine, up the TV antenna masts, then dissappears, and reappears
at the bottom.  You can hear the crackle 3 blocks away!

Ok, OK!  Enough already!  This was a test, yeah, that's it!  A test!
Just to see if you are paying attention (I sure wasn't!).

Maybe, just maybe, I just remembered wrong, and have now
checked, and it reads "30 ma".  I assure you, the neighborhood lights 
do NOT dim when I plug it in.

Well, it certainly generated some lively (albiet monotonous) discussion!
:-) :-) :-)

---
Rick Inzero				        rochester!cci632!rdi
Computer Consoles Inc. (CCI)			uunet!ccicpg!cci632!rdi
Rochester, NY					rdi@cci.com

"Your grandmother never, ever called me stupid.  
	She always called me 'pinhead'." -Jimmy Stewart in 1988 Campbells Soup
								commercial.
Organization: Ege University - Computing Center
Date: Monday, 13 Apr 1992 11:50:25 TUR
From: <OBL8956@TREARN.BITNET>
Newsgroups: sci.electronics
Subject: Re: Color monitor problems; got a magnet near it by accident.

   I did the same to our television once. The resulting colors were very nice,
but they are permanent. Hopefully noone was at home. I tried to fix the problem
 quickly. I did not know degaussing at that time. So i reversed the magnet
 ( N-S ) an applied at the same point. After a few tries the screen was brand n
ew !. At least to human eye :-)
  I agree, this could be pure luck but it worked..

-Turker
From: jimc@isc-br.ISC-BR.COM (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: DC Shock
Date: 15 Apr 92 01:30:47 GMT
Organization: ISC-Bunker Ramo, An Olivetti Company

In article <1992Apr11.233214.1969@doug.cae.wisc.edu> kolstad@cae.wisc.edu (Joel Kolstad) writes:
>If you want to talk about taking this idea a little too far, perhaps we
>should discuss cattle prods.  I've been told that these things are
>quite painful to the beast of which they're applied...

If you have never worked with cattle, they can be quite a treat.  As a
rule they are very stupid and stubborn beasts.  They outweigh you by
several times, and are very strong.  They are not pets, they don't get
extensively worked with by humans.  If you wrestle one on its terms,
you will lose.  Trying to move them around in enclosed spaces can be
difficult.  Usually they will go where you herd them, but sometimes
they get it into their head to balk.  They will crush you if you get in
their way at this time.  No amount of gentle persuasion will work.  A
jab from a prod will usually get them moving, more as a startlement than
severe pain.  I am sure it hurts, though.  (Still, it's better than using
a heavy club, which could do some real damage.)

As proof (sample of one) we had an electric fence protecting the barn.
To a human, getting zapped by one feels just like getting kicked.
Hard.  We were having a problem with one steer going through this fence
and getting in and pulling down the haystack.  Whatta mess.  Daily.
And with me getting tagged to fix the fence and clean up the mess each
time.  I lay in wait for him once, and watched him calmly walk 'under'
the fence.  All I saw was his skin twitch three or four times as he got
nailed repeatedly on his leisurely trip through.  No more Mr. Nice
Guy.  I got out an oil-burner ignition transformer and made an, umm,
_enhanced_ electric fencer, hooked it up, and lay in wait again.
(Sound/sight of soft blue coronas glowing around each fence insulator.)
Watched him come up for his free lunch.  Touched the fence.  Jumped
back hard, bellowed, and didn't stop running 'till he got to the other
end of the field.  I think I got his attention with that one, because
after that the problem stopped.  I replaced the normal fencer after that.

Moral:  Cattle are tough, and what would floor/kill you and me might
only  annoy the cow.

In retrospect, I should have toned down the enhanced fencer, it was
a little bit much.  But, we all do stupid things as kids, it's amazing
that any of us live to grow up.

+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			"PC's --- the junk bonds of the computer industry"
Newsgroups: sci.electronics
From: tadams@wedge.sbc.com (Tom. Adams 529-7860)
Subject: Re: Mercury Memory
Organization: Southwestern Bell Technology Resources, St.Louis, MO
Distribution: usa
Date: Thu, 16 Apr 92 15:43:03 GMT

In article <1992Apr16.120006.22253@uhura.neoucom.edu> wtm@uhura.neoucom.edu (Bill Mayhew) writes:
>idea of operation is similar to a so-called coherer dectector that
>was used in the early days of wireless.  In the latter, a direct
>current forms the bubble and the impinging radio signal breaks the
>bubble.  When the bubble breaks, a click is heard in headphones
>attached across the device.

A coherer was a dry device, consisting of very fine metal filings.
A strong radio signal produced a change in resistance, which produced 
a click in headphones.  The metal filings had to be tapped apart after
every signal, and special mechanical devices called tremblers would
periodically tap the coherer.  I believe you are thinking of the gas
barreter (spelling?) which consisted of a fluid, often acid, and a needle 
just touching the fluid surface. This device was preferred for a short
time because it was more sensitive than a coherer.
exte

--
Tom Adams	tadams@sbctri.sbc.com adams@swbatl.sbc.com   314-529-7860
misoneism (mis'-oh-nee-ism) n. Hatred of change or innovation. [Ital.
misoneismo: Gk. misein, to hate + Gk. neos, new.]  -- misoneist n.
No connection whatsoever to the word bureaucrat
From: pturner@eng.auburn.edu ( Patton M. Turner)
Newsgroups: sci.electronics
Subject: Re: Telephone Line Interface
Date: 6 Apr 92 02:25:05 GMT
Reply-To: pturner@eng.auburn.edu
Organization: Auburn University Engineering


In article 333@dean1.usma.edu, sr3745@dean1.usma.edu (Roeber Rodney MAJ) writes:
>I do not know how to tell when the calling party hangs up.
>    I can always delay.  If the Caller ID is unavailable/invalid and
>    the DTMF code is missing/invalid after some amount of time, I 
>    could just hangup.  There should be a better way, though.

Look for some form of CPC (calling party control).  If your CO
is so equiped, there will be a pulse on your line when the caller
disconnects.  AT&T CPE uses a .5 sec open loop pulse, what your
CO does, if anything at all, may be different.


>I do not know how to detect when someone picks up a phone in my home.
>    When someone picks up, it would be nice if I did not blast any more
>    personality rings!  Also, I would typically have my project go
>    hang up when someone in my home answers a phone.

Check for loop current on the other lines.  ie: tap the line for
you answering machine, the connect a current detector is series
with the remainder of phones in the house.

Pat Turner  KB4GRZ  pturner@eng.auburn.edu
From: dbell@cup.portal.com (David J Bell)
Newsgroups: sci.electronics
Subject: Re: 7 segment
Date: 9 Apr 92 04:53:01 GMT
Distribution: usa
Organization: The Portal System (TM)


>Anyone know where I could get large 7 segment displays?
>I'd like to make a timer, and a scoreboard.  I made some
>5" X 7" with LED's but I was hoping I wouldn't have to
>make anymore because they are kind of a pain.
>Thanks!!  Oh, it doesn't have to be a certain size, just
>pretty large would be good.

>rob
>uhcc

You might want to take a step back to older technology, and
use edge-lighted plastic sheets for the segment bars.
Cut triangular segments of thick acrylic, with the base
lenght equal to the bar size you want, and the height
rather less, maybe half the base. Drill through close to
the apex (opposite the base), and insert an incandescent
lamp. Mount the base edges through slots in the background
material, and drive the lamps with power drivers off a
normal 7-segment decoder.

Dave
From: tonya@hpldsla.sid.hp.com (Tony Arnerich)
Date: Wed, 15 Apr 1992 01:55:49 GMT
Subject: Re: Before camcorders - info wanted
Organization: HP Scientific Instruments Division - Palo Alto, CA
Newsgroups: sci.electronics

In sci.electronics, bryanh@hplsla.hp.com (Bryan Hoog) writes:

>       Before camcorders, there were video cameras.  A bit smaller than
...
>     - The connector appears to be standard between vendors.  Is (was) it?

If I remember correctly, there were VHS connectors and Beta connectors.
I have no idea if they needed anything different going on, all I knew
about was a different implementation. I believe there were VHS-Beta Camera
Converter boxes available, and vice versa.

>     - Can the camera be made functional without the VCR?  In other words,
>       can I put in power and get out video?  Or was some important part
>       of the electronics in the VCR portion (scanning circuits, etc)?

There were power supplies that you plugged the camera into, which in turn
had video-level outputs (not RF). And audio outputs, of course.

>     - Any ideas where I could get documention on the connector?

Perhaps Sams Books has a title on Video Camera and VCR repair, etc.

>     - Finally, how does the picture quality in these old cameras (vidicon
>       tubes?) compare with the new CCD technology?  

Vidicon: low sensitivity, radial blooming (spreading outward from point)
Saticon: a little better?
Newvicon: Much better on both counts.
CCD: Line-wise blooming, best sensitivity (perhaps mainly due to having the
benefit of being on the market during the last few years. Maybe Newvicons
would be as good as CCD's, given only that R&D had continued). The line-
oriented blooming IMHO is a regression.

tonya@hpldsla.sid.hp.com

Newsgroups: sci.electronics
From: gordonl@microsoft.com (Gordon Letwin)
Subject: Re: goodbye Heathkits
Date: 09 Apr 92 16:39:39 GMT
Organization: Microsoft Corp.

In article <754@amtfocus.amt.gss.mot.com> wolfson@amtfocus.amt.gss.mot.com (Steve Wolfson) writes:
>
>One of the problems is that as consumer items becames technically more
>sophisticated it became hard for Heathkit to design items that both
>were a match technologically and at least somewhat competitive in price.

Another aspect of the "kit vendor" problem that I haven't seen discussed
is testing.  In addition to building the kit, users want it to work!
Heath had to build their systems in such a way that they could be aligned,
adjusted, and diagnosed with very simple tools, usually built into the
kit.

So you'd move some jumpper and turn some trimpot until a LED went on or
off.  But as electronics became more and more sophisticated
this became more and more difficult.  A commercial vender could use 10%
parts and then have a tech - equipted with a $50,000 bank of gear - spend
3 seconds turning a couple of trimmers to align the unit.  Heath would
have to use hi precision parts and perhaps more expensive circuit designs
so that the unit woulnd't need alignment.

Likewise, commercial gear can be diagnosed with a lot of fancy pre-programmed
gear like bounds checkers and signature analyzers; the Heath stuff didn't
have this option.

So the little problem was that Heath had to design stuff to be "self adjusting"
for the entire tollerance range of it's components and circuits.
A bigger problem is that as stuff gets more complex and smaller the error
rate rises, yet the gear's testability on a kitchen table dramatically
declined.  (Ever try to find a dead bus buffer with a $15 voltmeter?)

	gordon letwin
Newsgroups: sci.electronics
From: stlucas@gdwest.gd.com (Joseph St. Lucas)
Subject: kxp1124 printer
Organization: General Dynamics Corp.
Distribution: na
Date: Wed, 8 Apr 1992 17:23:26 GMT

Hello,  I have a panasonic kxp-1124 printer hooked to my computer.  The
manual says it has 6k print buffer memory, expandable to 32k.
Has anyone done this expansion themselves, or know how to do it, etc.
I don't mind playing with the innards of the machine if I know new chips
(and where to put them) will do it.  THanks.
stlucas@gdwest.gd.com
Newsgroups: sci.electronics
Subject: HELP needed with Phase Comparator
From: geoffrey@cosc.canterbury.ac.nz (Geoff Thomas)
Date: 8 Apr 92 14:34:07 +1200
Distribution: world
Organization: Computer Science,University of Canterbury,New Zealand


Hi, I'm looking for a circuit that will produce a voltage
proportional to the phase difference between to input signals
(both about 300 MHz). The circuit needs to be accurate to at
least 0.1% or lower. I'm not much of a wiz with components,
so the simpler the better (KISS theory).

Any ideas, etc. much appreciated.

Thanks in advance,


Geoff Thomas.

Newsgroups: sci.electronics
From: toddi@mav.com (Todd Inch)
Subject: Re: Paranoid about my hz?
Organization: Maverick International Inc.
Date: Fri, 17 Apr 92 15:53:29 GMT

In article <11994@ns-mx.uiowa.edu> jagnow@al.weeg.uiowa.edu (Al Jagnow) writes:
>In article <26MAR199218312769@elroy.uh.edu> englhq@elroy.uh.edu (Franklet,  
>Duane L.) writes:
>> This is a simple question for any of you. If I want to use an over the
>> counter step down transformer so that I can use my printer in Germany,
>> do I need to be concerned about the difference in hz?
>> 
>> I have been told that what goes in comes out, so I will be feeding
>> the printer 110 at 50 hz, and the printer specs say the source should
>> be 110, 60hz plus/minus 3hz. 

Yes, "what goes in comes out" with regard to frequency.  It takes much
more than a simple transformer to change the frequency.

Many electronic appliances are specifically marked 50/60 Hz on their
nameplate, especially the ones with a 110/220 V switch.

I did read somewhere, probably in a Toshiba printer owner's manual,
that while there product usually did work on 50 Hz, it was not
guaranteed or recommended, that it would likely shorten the printer
life (something ran a little hotter than intended, I believe) and would
void the warrantee.

If you will be frequently going back and forth between north america
and europe, I'd recommend finding a printer which is 110/220 V
switchable and also rated 50/60 Hz, which shouldn't be all that
difficult.  Recently, I've even seen some computing equipment that
AUTOMATICALLY switches between 110 and 220, or possibly it doesn't
really "switch" at all but just has a very tolerant power supply input
range.
Newsgroups: sci.electronics