HDTenEightyP/NetNews huggingface dataset:
From: neal@cmptrc.lonestar.org (Neal Howard)
Subject: Humidity Sensor Needed (Cheap!!!)
Date: Wed, 26 Aug 1992 00:01:56 GMT
Organization: CompuTrac Inc., Richardson TX

Can anyone out there help me with my search for something to use as an
electronic relative humidity sensor. So far my search has revealed the following
methods for building a sensor device for use in constructing an electronic
hygrometer I wish to interface to my PC:

1) I've been told of a synthetic rope-like material impregnated with graphite,
   powdered metal, and ionic salts for which the electrical resistance will
   change logarithmically with the relative humidity of the air around it.
   The engineer who informed me of this item works for a commercial
   meteorological instrumentation firm and cannot reveal the source of such
   material or the details of making it myself since his company 
   considers it a trade secret. The biggest advantage was that it doesn't
   require much in the way of temperature compensation and makes for an
   extremely accurate(less than .5% error), maintenance-free sensor.

2) An open, humidity-sensitive, thin-film-dielectric capacitor may be 
   constructed, but will require serious temperature change compensation and
   must be sealed inside some kind of housing that is almost airtight but would
   be porous enough to let the water molecules in the air through but keep
   keep out pollutants which could contaminate the delicate capacitor, like
   a porous ceramic case. This device could be used to control
   the frequency of an oscillator, whose output would be run through a
   frequency-to-voltage converter then through an A/D converter to give me
   the binary form I really need for my software to use. This sensor is 
   subject to false readings if the temperature compensation circiutry
   doesn't work perfectly. I don't think the accuracy is much better than 2%
   either plus there is a time lag for the water molecules in the air to
   penetrate the porous ceramic housing.

3) The ugliest way would be to employ a wet/dry pair of electronic thermometers
   and use software to calculate the relative humidity from the temperature
   difference. Yuck!!!! I really don't want to maintain a water supply and the
   necessary mechanical junk that would go along with this method.

Surely there must be some kind of easily obtainable or constructable relative
humidity sensor that can give an instantaneous, accurate (within 1%),
electronic signal output (I can convert from resistive, capacitive, or 
current generating) that would be inexpensive and maintenance-free.
If anyone out there knows of such a device, I would appreciate it very much.

Thanks, 
Neal Howard
email address => neal@cmptrc.lonestar.org 
or just post to sci.electronics, there may be others interested in this topic.
=======================================================================
From: nagle@netcom.com (John Nagle)
Newsgroups: sci.electronics
Subject: Re: Need encoding scheme for TV remote infrared controller
Date: 3 Sep 92 18:11:10 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

Re IR remote controls for consumer electronics:

      It's not that bad.  Motorola has components for all the remote
control functions, and you can get the data sheets and see how it's done.
The MC14497 is a "dumb" one-chip IR remote control IC, intended to
be driven by a 4x4 keypad.  The corresponding receiver is a MC3373P.
This outputs a TTL bitstream.  There's a newer part, the MC44520 RC
Receiver, which is part of Motorola's chip set for TV receivers.
There's also an application note, AN1016, Infrared Sensing and Data
Transmission Fundamentals, which may be useful.  Motorola info can
be obtained from their tech hotline, 1-800-521-6274.  [JN, Sep 92]
From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics
Subject: Re: Success! Resist Pen Works in HP Plotter!
Keywords: resist pens, pcb, etching
Date: 4 Sep 92 08:46:02 GMT
Organization: Acorn Computers Ltd, Cambridge, UK

In article <78655@ut-emx.uucp> david@moe.ece.utexas.edu (david lee) writes:
>
>And in the catagory of 'Best Pen to Withstand Etching of Copper Clad
>Circuit Board Using Ferric Chloride' the winner is....
>
>Manufacturer: Staedtler
>Model: Lumocolor 313 AV
>Ink color: Red
>
>This Pen is available in several sizes; The S size has a 0.4mm tip
>which is PERFECT for running traces *between* the 0.1 inch spacing
>of DIPs. After Etching the boards in warm ferric chloride, every other ink

.. and also in several shapes, including some that are made to fit HP
plotters ! After noticing that the plotter pens I was disembowelling to
fit Lumocolor tips into were also made by Staedtler, I went hunting for
an OHP plotter pen from the same company.

They make :

	31HP07K-2	0.7mm, short pen for 7220 and similar
	31HP03K-2	0.3mm, ditto
	31HP03L-2	0.3mm, long pen for Draftmaster etc.

(-2 indicates red ink)

I tried the 31HP03K-2 last night and it appears to be exactly the same ink
as the 313 AV. It certainly works as well !
The tip on this pen is similar to that on the 'Fine' (318 AV ?) Lumocolor,
and suffers slightly from poor ink transfer - fine lines appear in the resist,
and it leaks slightly. I had this problem with all the Lumocolor pens I tried,
to a greater or lesser degree. It certainly appears to be worthwhile plotting 
the tracks twice (or perhaps using a very slow plotting speed) as another
writer suggested.

-adrian


-- 
Adrian Godwin : agodwin@acorn.co.uk : adrian@fangorn.demon.co.uk : g7hwn@gb7khw
ObDisclaimer  : I believe this rubbish .. don't imagine that anyone else does.
Newsgroups: sci.electronics
From: larryc@netcom.com (Larry Ching)
Subject: 100VDC Lamp Modulation
Date: Sun, 30 Aug 92 02:47:57 GMT
Expires: Tue, 15 Sep 92 07:00:00 GMT
Organization: Netcom - Online Communication Services (408 241-9760 guest)
Summary: A request for information on modulating regular incandecent bulbs
Distribution: sci.electronics
Keywords: incandescent, modulation 


 I'm trying to find out if what I'm planning to do has been done before.
I want to use 100VDC to power an incandescent lamp circuit, that will
drive regular light bulbs with sine waves in the frequency range of 1HZ
to 30HZ. The sine waves will be +VDC offset, so that the most negative peak
of the sine wave corresponds to 0VDC. The amplitude should be controllable,
but that can be sacrificed in the early versions of the circuit.

 If this has been done before, I'd like some reference information. I'm
looking for design hints and constraints.

                                       Thanks!
                                       Larry Ching / larryc@netcom.com

-- 

 *---------------------------------------------------------------------*
 | "Listen carefully to the music, and dance like a flower"            |
 |  ----> BODY OF LIGHT:"Dance Like A Flower"      larryc@netcom.com   |
 *---------------------------------------------------------------------*

Newsgroups: sci.electronics
From: rubin@glockenspiel.cis.ohio-state.edu (Daniel Rubin)
Subject: Re: <<<<<FOR SALE  68030 33MHz. - $300  shipping paid by me
Keywords: 68030
Organization: The Ohio State University Dept. of Computer and Info. Science
Date: Fri, 4 Sep 1992 17:01:04 GMT

>>Now look at the 80386 -40 (or Intel -33, whatever).
>>Who uses this CPU?  many many open MS-DOS/Unix/whatever systems.
>>Cost for the motherboard and CPU?  -> $225.
>
>	The lesson: a part like the 80386, which is generic (and available
>from two independent sources, AMD and Intel) is less expensive than
>a part like the 68030, which is not available in a 'clone' from
>any second source.
>
>	Anyone else want to start up an 'Open Hardware Foundation'?
>
>	John Whitmore

Hmm... Well I do agree with your theory that identical parts available from
several sources should be less expensive than a part only available from
a single source but...

Here are the microprocessor prices directly out of the 1992 JDR Microdevices
catalog #21 !

68000 $6.95 <- wow very cheap considering
68020 $189.95

80286-8Mhz  $12.95

80386-20Mhz  $ 269.95
80386-25Mhz  $ 289.95
80386-33Mhz  $ 299.95
80386-40Mhz  $ 329.95 <- you are getting a hell of a deal on that board!

80486-33Mhz  $ 599.00
80486-50Mhz  $1199.00 <- Ack!

I never knew that popular microprocessors were so exspensive.  By the way the
speeds of the 6800 series were not listed like the 8000 series.  All these
microprocessors are sold as single pieces which jacks up the price, but all
is relative and the 68020 is much cheaper than a 20Mhz 80386 and you can get
a 68000 for nothin which I would much rather work with than a 8Mhz 80286 !!  
The 68030 is not listed in that catalog.

								   - Dan
-- 
  Daniel Joseph Rubin    |  "...A good football team for the alumni, parking
rubin@cis.ohio-state.edu |  for the faculty and sex for the students."
      GO        GO       |  - President E. Gordon Gee on the three things that
    BENGALS  BUCKEYES    |  a great university president must provide.....
Newsgroups: sci.electronics
From: hgw@julia.math.ucla.edu (Harold Wong)
Subject: contact cleaner
Organization: UCLA Mathematics Department
Distribution: usa
Date: Wed, 26 Aug 92 22:43:50 GMT

I am in need of about 5 gallons of electronic contact cleaner/degreaser to
clean about 50 keyboards.  I've been using Blue Shower (tm) in small
quantities but now I need alot.  The price per gallon is about $100. 
Anybody know of a generic brand of contact cleaner for a better price? 
It must be safe on plastics. Thanks.

-------------------------------------------------------------------------------

Harold Wong         (310) 825-9040 
UCLA-Mathnet; 3915F MSA; 405 Hilgard Ave.; Los Angeles, CA 90024-1555
ARPA: hgw@math.ucla.edu          BITNET: hgw%math.ucla.edu@INTERBIT
Newsgroups: sci.electronics
From: RSPEIRS@130.187.170.178 (RON SPEIRS)
Subject: Wanlass Paraformer - does anyone remember?
Organization: Evans & Sutherland Computer Corp.
Date: Fri, 4 Sep 1992 17:09:56 GMT
X-News-Reader: VMS NEWS 1.11

About 10 or 15 years ago, I remember reading advertising literature from
a company called Wanlass.  They had invented a unique kind of transformer
and power supply (with the trademark of Paraformer or Parax?).  This
transformer was built differently than ordinary transformers, in that
one winding was rotated 90 degrees from another winding.  The literature
went into the theory of how this transformer utilized a "parametric"
term in the transformer equations, which in most other cases was ignored.
(If I'm not quite right on these details, it has been a long time since
I have seen the literature.)  The transformer was claimed to have
better regulation than other transformers.

Does anyone remember this company or have any of their literature?  This
is strictly a curiosity search to satisfy a discussion among my fellow
engineers.

I called a company which had bought the patent rights and the name
"Paraformer":  Adtech Power in Anaheim CA, but the engineer there said that
they had been bought and sold several times and that the paraformer
technology was "dead".  He didn't have any information on it.  I suppose
that todays switch-mode power supplies have eliminated the need for the
paraformer technology.

If anyone has any remembrances, experience or literature on this product,
I would appreciate hearing from you.  Please send E-mail since I don't
read this news group very often.  Thanks in advance.

Ron Speirs, Evans & Sutherland Computer Corp., Salt Lake City, Utah 84108 
            600 Komas Drive          (801)582-5847

Newsgroups: sci.electronics
From: frank@rover.uchicago.edu (Frank - Hardware Hacker - Borger)
Subject: Re: Mail-order sources for picture tubes?
News-Software: VAX/VMS VNEWS 1.41    
Reply-To: frank@rover.uchicago.edu
Organization: Joint Center for Radiation Therapy
Date: Thu, 3 Sep 1992 00:19:00 GMT

In article <1992Sep2.190645.1010@keinstr.uucp>, marks@keinstr.UUCP (Mike Marks) writes...
> 
>Greetings,
> 
>Does anyone know any mail-order sources for TV picture tubes/
>projection TV tubes?  I was wondering if it's possible to save
>by replacing tubes myself instead of paying the local shop 
>markups for the tubes & labor.  Yes, I have my TV's service
>manuals & access to plenty of test equipment here at work.

	I've done it, it's pretty easy. 

	1/ As per previous suggestion, best is to look for a local jobber
	   for the tube.

	2/ Wierd trick to do convergence without a pattern generator. Do
	   it on Saturday morning. (Why you ask? Because cartoons, especially
	   the cheaper ones with less motion are ideal for checking convergence.)

	3/ Only kicker is to be very careful when disconnecting the HV anode
	   lead. 

   Frank R. Borger - Physicist    __       Internet:  Frank@rover.uchicago.edu
Michael Reese - Univ. of Chicago |___      Phone : 312-791-8075 fax : 567-7455
  Center for Radiation Therapy   | |_) _   
    2929 South Ellis Avenue        | \|_)  I used to be Snow White, but I
    Chicago, Illinois 60616           |_)  drifted. Mae West
Newsgroups: sci.electronics
From: 10666281@eng2.eng.monash.edu.au (KEVIN PRATER)
Subject: Does 74LS88 Exist
Organization: Faculty of Engineering, Monash University 
Date: Mon, 24 Aug 1992 01:00:43 GMT

	I'm trying to find out if the chip 74LS88 exists!
The diagram I have uses it but I looked in the 1986 Philips specs and they 
didn't have it. The closest I found was the 74LS86 (Quad two input 
exclusive OR Gate) which seems to be two '88's stuck together.

	Also is there a 74LS07 Hex buffer/driver (open collector) or
did they mean to say the 7407. As this is another chip I can't seem to 
find.  

Thank again
Kevin Prater
Newsgroups: sci.electronics
From: massoud@chemteca.sdsu.edu (Massoud Ajami)
Subject: Re: how do you figure out cost per kilowatt-hour?
Summary: need for figure out costs for power consumption
Organization: San Diego State University
Distribution: na
Date: Tue, 1 Sep 1992 15:42:30 GMT

In article <124@kc2wz.bubble.org> bob@kc2wz.bubble.org (Bob Billson) writes:
>From: bob@kc2wz.bubble.org (Bob Billson)
>Subject: how do you figure out cost per kilowatt-hour?
>Summary: need for figure out costs for power consumption
>Date: 31 Aug 92 20:28:42 GMT
>I need to determine how much some particular electronic is costing me to run.
>For the sake of example, I need to know the cost of running something consuming
>100 watts, all day long, all month long.  I know the cost the power company
>charges per kilowatt-hour.  Can someone provide an equation to convert the
>equipment's power rating to kilowatt-hours?
>
>Simply using:
>
>         (power_rating/1000) * hours_used * days_used
>
>does not work out correctly (or so it seems).  Help? :-)  Thanks
>
>       Bob
>-- 
>  Bob Billson, KC2WZ                          | internet: bob@kc2wz.bubble.org
>                                              |           kc2wz@amsat.org
>  $nail:  21 Bates Way,  Westfield, NJ 07090  | uucp:     ...!uunet!kc2wz!bob
>                  C code.  C code run.  Run code run...<please!>

Equipment power rating is Watt-hour, so kilowatt-hour is watt-hour/1000.
Of course this is for resistive loads like light bulb, iron, toaster,....

      (power-rating/1000) * hours_used * cost $/kwatt-hour =total cost $.

units:       kwatt        *    hour    *      $/kwatt-hour = $.



Peace and Prosperity!
  ---==< 110 >==---
Newsgroups: sci.electronics
From: gary@kimbark.uchicago.edu (Gary Mr.OS/2 Buchholz)
Subject: Need info on Power Inverters & why some devices dont like sq waves
Reply-To: gary@midway.uchicago.edu
Organization: University of Chicago Computing Organizations
Date: Thu, 27 Aug 1992 22:11:55 GMT

Ok, Here's a simple question - I hope.

I've seen alot of ads for power inverters.  Thats is, devices that take 
12V DC and convert it to 120V "AC".

Some ads for power inverters explicitly state that they generate square
waves rather than sine waves.  Further, the ads state that "some devices"
will not run properly with this inverter.

Question 1 - Are all inverters in the $50-$100 price class "square wave"
	    generators.  Are there inverters that generate true sine waves?

Question 2 - WHAT devices wont work with square wave AC.

It seems to me that the RMS voltage would be different in square wave vs
since waves... and possibly fake out a switching power supply... as used
in computer equipment.  

If the device ultimately steps down the volatge through a transformer and 
LC filter network and regulator.. it shouldn't matter if the AC is square 
wave ... ?

Anyone got the scoop on power inverters?

Thanks,
  Gary
-- 
Gary Buchholz / KE9ZM			Internet: gary@midway.uchicago.edu
University of Chicago			Packet:   KE9ZM@N9HSI.IL.USA.NA
Academic and Public Computing		
1155 East 60'th St., Chicago, Ill.	(312) 702-7611
Newsgroups: sci.electronics
From: carrasco@bmers263.bnr.ca (Sylvano Carrasco)
Subject: Re: Need encoding scheme for TV remote infrared ... 
Organization: Bell-Northern Research Ltd, Ottawa, Canada
Date: Wed, 02 Sep 92 20:29:44 GMT

Keith Mancus states
> Odd. I've seen "generic controllers that can be programmed to drive a wide variety of remote-
>controlled devices.

To re-iterate, MOST TV IR-remotes use a 40 Khz carrier.  The generic controllers take advantage
of this.  There are basically two types of 'generic remotes'

I)  The first one is the type that has a IR sensor (a photocell/phototransistor) but into it.
You program the 'generic remote' by aligning your TV/Stereo/CD/VCR remote head-to-head with the
'generic remote'.  You then press one button on the original remote.  The 'generic remote' 
senses the pattern (or modulation) for that particular button and saves it in memory.
Essentially the 'generic remote' is sampling the output from your original remote.  

If you are interested in building/understanding how generic remote controllers like this work,
dig up an old issue of Byte magazine.  I don't have the reference but Steve Ciarcia (now the
editor of Circuit Cellar Ink) had a project where he designs a trainable remote control.  I'm
sure this article will be of help. (Try BYTE circa 1985, 1986).  There's a pretty in depth
discussion of how the IR works.

II)  The second type works on somewhat trial and error.  This is the type of controller you
get on some VCRs that can also control your TV (at least that's what my new VCR controller can
do).  Basically, the remote-control has stored some patterns that are standard for a number of
different TVs (i.e. SONY uses the same pattern[modulation] on all their TVs so you can take 
your remote to a friend's place and play mind games with him as you mysteriously change channels
during the ball game {I've tried this...trust me hours of entertainment as he gets up to smack 
his $1000 TV}.  So basically the controller has to figure out which set of patterns it should
assign to all the buttons.  There's a program button on the 'generic controller'. To train the
remote, the instructions tell you to start pressing buttons randomly.  You will get weird 
behaviour, i.e. pressing 5 will cause the volume to increase and pressing ON will change the
channel. Once you find the button that makes the channel go 'up', you then press the 'program'
button.  The controller can then map which is the correct set of patterns for each button by
looking in its memory for that match.

Hope this helps

-- 
Sylvano

+------------------+------------------------------+----------------+
|  Sylvano Carrasco|   Bell-Northern Research     |  #define       |
|                  |   P.O. Box 3511 Station 'C'  |     Opinions   |
|  (613) 763-4109  |   Ottawa, Ontario.           |        My_Own  |
|                  |   Canada.  K1Y 4H7           |                |
+------------------+------------------------------+----------------+
Newsgroups: sci.electronics
From: ghuntres@nyx.cs.du.edu (Gary  huntress)
Subject: substitution of logic families
Keywords: ttl cmos als substitution
Organization: University of Denver, Dept. of Math & Comp. Sci.
Date: Fri, 4 Sep 92 19:16:35 GMT


Can LS, ALS, and CMOS (pin compatible) components be substituted
for TTL parts in general?  I've got an "old" TTL system that needs
a couple of spare parts, do I need to agonize over speed, power, fan out
rise times.......or are the newer logic families always "better"?
From: exumfox@exu.ericsson.se (Mike Fox)
Newsgroups: sci.electronics
Subject: Re: Where to buy parts
Date: 24 Aug 92 23:02:21 GMT
Reply-To: exumfox@exu.ericsson.se
Distribution: dfw
Organization: Ericsson Network Systems


Off-the-Shelf has a good selection (high prices though)
it is North of Arapaho and West of Plano Road. Their
van is usually sitting out front. Their door faces the
south and you can't see it from Plano Road.

There is another place nearby South of Campbell and
east of Greenville. Electronics Parts Outlet (I think
that is what it is called) It is next to some kind
of sporting goods/ski store. They have a lot of 
strange stuff.

For bargains - try 1st saturday. Every 1st Saturday
of the month there is a huge swap meet in downtown
Dallas.  Ross street and Central Expressway.

I don't get any kickbacks from these places or know
anyone who works there. They are close to where I
work and frequent them often.

/Mike
From: krueger@cal.enst.fr (Martin Krueger)
Newsgroups: sci.electronics
Subject: Anyone knows "Ansafone" ?
Date: 31 Aug 92 12:08:19 GMT
Organization: Telecom Paris


Hello !!

Does anyone on the net has ever heard of a company named "Ansafone" ? The
company doesn't exist any more, as does the french distributor.

I have a very sophisticated (although it is from 1977) answering-machine of
that brand. I'd like to get it going, but there is a problem. Basically, the
machine doesn't hook off when the phone is ringing. The recording tape seems to
work normally (it's a highly complex 3-motor reel-to-reel!), as does the
announcement-tape. Since I don't have the handbook, I cannot tell wether this
is due to a failure in some circuit or wether I overlooked something.


!!!!! Help of any kind (even encouragements, sic) is greatly welcome !!!!!
		
		M A R T I N

---------------------------------------------------------------------------
Quoting what I found on the rear of the cabinet 
(It has been sold in France):

"ANSAFONE LTD. Camberley ou London
 Mark VIIP
 Annee 1977   No 224765

"Societe BLANC                         /* must be the french distributor */
 11 Bis Rue Pasteur
 l'Etang la Ville 78620

"Conforme au modele agree par l'Administration des PTT
 Agrement No 73-30 TPH du 2.3.1973
 Schema No 7000 planches 1 a 4 Edition 1


That's all folks...
Newsgroups: sci.electronics
From: wa2ise@cbnewsb.cb.att.com (robert.f.casey)
Subject: DC-DC converter in my RCA VLT260 VCR runs too hot?
Keywords: PADS schematics
Organization: AT&T
Date: Mon, 31 Aug 1992 17:48:45 GMT

Just replaced a DC-DC converter module in a RCA VCR, model VLT260
(made by Hitachi, I think).  The old one burned out, and the new one
gets awfully hot, a bit too hot to touch.  Can't find any overloads
on the outputs, voltages correct.  Before I installed the new one, I
used some bench power supplies to supply the voltages that this
thing generates, and didn't see any seemingly exeessive current demand.
Other power handeling parts of this VCR also run hot, so maybe this
module getting hot is normal?  If so, than i'd call it marginal
design.  I stuck a heat sink on the module to try to cool it some.
Anyone have experence with this or similar VCRs?
Newsgroups: sci.electronics
From: cscc13@judy.uh.edu (NAVEED IQBAL)
Subject: NTSC to PAL	Did anyone try?
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Houston
Date: Fri, 28 Aug 1992 21:30:00 GMT

Did anyone try converting NTSC to PAL system? 
I hear some people does the conversion but I don't know how.

Naveed
NIqbal@uh.edu

Newsgroups: sci.electronics