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"Dave M" <dgminala@mediacombb.net>: Sep 22 10:53AM -0500 Dave M wrote: > D'Arsonval movements have about 20-30% range on the > mechancial zero adjustment, so yours might be a long stretch for this > method. Never know till you try!! Dave M     I forgot to mention that for the zener solution, you really need to select as low power a zener that you can find, such as 400mW or lower. The 1N4104 is a 10V, 250mW zener, with a test current of 1uA, and a max current of 25ma, well within your requirements. In stock at Mouser.com.   Cheers, Dave M

Jeff Liebermann <jeffl@cruzio.com>: Sep 22 10:22AM -0700 >It's what you do when you don't understand what you need, but you >start building it anyway.   >If you need precision, you don't want an analog meter.   In college (about 1969), I build an "electronic slide rule" in the form of an analog computer inside a brief case. Inside, it was two log amps, a multiplier, range switch, and an anti-log amp. Input was via two Bournes Helipot 10 turn pots (linearity 0.1%). Output was on a mirrored scale analog panel meter about 6" in width. Accuracy was 3 decimal places in the lower part of the meter, and 2 decimal places over the rest of the scale. However, I had to use temperature compensation tables for the pots, multipliers, and amps to obtain that level of accuracy.   What level of precision were you expecting?   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Ian Field" <gangprobing.alien1@virginmedia.com>: Sep 22 08:27PM +0100 "T i m" <news@spaced.me.uk> wrote in message news:e898schb0qaru15b36kmcfvrroth86grt6@4ax.com... >>kind of power supply.   > Because the reference voltage will be too close to the minimum voltage > expected Ian?   The TL431 is actually a comparator with its own built in 2.5V reference.   In closed loop operation, that's as low as the cathode goes - you can saturate it in open loop operation, but "Vce-sat" is around 2V.

whit3rd <whit3rd@gmail.com>: Sep 22 02:13PM -0700 On Thursday, September 21, 2017 at 10:51:33 AM UTC-7, T i m wrote:   > I was thinking of using either a voltage reference such as > LM4040DIZ-10.0 or could I get away with a simple zener (BZX55C?) with > associated resistor(s) please?   You can use any zener under 10V to do a 10V zero offset (just divide down the input voltage until that 10V input matches the zener knee). So, with an arbitrary zener (I'd use a TL431 as a 2.5V reference, they're convenient and accurate) and a trimmer acting as voltage divider, it just remains to make a range-setting resistor in series with the meter.   The important thing, is to doodle up a really nifty scale for your meter that indicates 10V to 15V, with clear markings, along the pointer's arc, maybe with a bunch of subdivision marks. Last time I did that, it took a plotter and a bit of custom software to draw the arcs and labels, then some fiddling with the faceplate of the meter to affix it (warning: you need to worry about laser-print ink, paper, glue compatibility).

tabbypurr@gmail.com: Sep 22 03:38PM -0700 On Friday, 22 September 2017 05:05:35 UTC+1, Jeff Liebermann wrote:   > "The Windows programs for drawing analog meter scales" > <http://www.tonnesoftware.com/meter.html> > $35 for the full version.   fails to solve the issue AND adds pointless cost.     NT

tabbypurr@gmail.com: Sep 22 03:39PM -0700 On Friday, 22 September 2017 05:22:46 UTC+1, Foxs Mercantile wrote: > > simple but time consuming producing a new dial paper   > With the low current Zener, it doesn't look like that will be > necessary.   Oh, you've found a zener that's 10v +/- 1%?     NT

tabbypurr@gmail.com: Sep 22 03:45PM -0700 On Friday, 22 September 2017 05:42:36 UTC+1, mike wrote:   > >> End rant.   > > He's making a one off for use at home, not commissioning a new design of military hardware.   > The task is the same no matter who the customer.   Rubbish. For a large project all the specs have been calculated to meet the requirements, the contract gone through by a team of lawyers, and the task of the lec eng is to produce a circuit that meets all the given specs under all specified conditions.   For a one off at home the requirements are often not pinned down firmly, as in this case. There are no lawyers, no contract, and the elec eng's job is to trade off cost & complexity versus specs to find what turns out to be the most agreeable compromise for the client, oneself. In most cases this is a device that is much less tightly specced.     NT

tabbypurr@gmail.com: Sep 22 03:48PM -0700 On Friday, 22 September 2017 05:43:10 UTC+1, mike wrote: > the precision measurement desired is never entered into > any other system/program. The desired functionality > could be obtained by a Sharpie mark or two on the face of the meter.   Indeed. This can be done in such a way to make it tidy. But the use of a zener means the scale will have to be calibrated, which is a waste of time, especially to get a nice neat result.   > It's what you do when you don't understand what you need, but you > start building it anyway.   > If you need precision, you don't want an analog meter.   I see it's foolish claims day today.     NT

tabbypurr@gmail.com: Sep 22 03:57PM -0700 > On Thu, 21 Sep 2017 17:21:23 -0700, mike <ham789@netzero.net> wrote:   >Words like exactly, "as good as possible" have no place in a specification.   a common enough phrase for an in-house spec. Such phrases should be cleared up later of course, once the specifier knows what the engineers can actually do and what the options cost.     > >Specs are numbers and test methods. Specs include allowable > >variations due to initial component tolerances, component age, > >temperature, vibration, misuse.   Some do. Some are 'how can you get it as cheap as possible and still have it sell & not destroy our repuation.' Some are 'we want to beat what's out there, how good could you get it?' Some are 'we want it to do this.' etc etc etc.     > readings interpreting and so ITRW, we are 'most likely' to not require > much in the way of precision or we wouldn't be using those things in > the first place. ;-)   1% is doable for some analogue meters. That's enough precision for a lot of tasks.     NT

amdx <nojunk@knology.net>: Sep 22 08:13PM -0500 > Had I known, the "meter man" at Kutztown would have had exactly what you want in the size you want it, new or used. He has hundreds. Now you have to wait until spring.   > Peter Wieck > Melrose Park, PA   I don't know if you are asking for an expanded scale meter, were the 0V line is 10V and FS line is 15 volts, so the whole range is only 5 volts. That's what I gleaned. First you need to put a series 60K ohm resistor to make the meter read FS with 15V applied. (for accuracy you should subtract the resistance of the meter from the 60K ohms) Then you need to add a circuit shown in these sites.   > http://www.radcomms.net/Expanded_Scale_Voltmeter.html   http://www.thebackshed.com/windmill/articles/ExpandedScaleVoltMeter.asp   > http://www.zbasic.net/forum/about1423.html   This last one will probably need a 10K resistor tied from one OUT to the other OUT. Just so there is enough current to make the regulators work properly.   Here's a youtube, I didn't watch it all, but you might learn something.   > https://www.youtube.com/watch?v=-z_j4MclCTk   Mikek

bruce2bowser@gmail.com: Sep 23 12:03AM -0700 mike wrote: > >> End rant.   > > He's making a one off for use at home, not commissioning a new design of military hardware.   > The task is the same no matter who the customer.   At least the extra option should be there.

Jeff Liebermann <jeffl@cruzio.com>: Sep 23 09:35AM -0700 >> $35 for the full version.   >fails to solve the issue AND adds pointless cost. >NT   The consensus seems to be to use an expanded scale analog voltmeter. If the OP is going to build such a thing, he needs a new scale on his analog meter. That can be done with the free version of the software. (I just checked and it will do an expanded scale).   I usually ignore one line pontifications, but I'm curious. Why does a new meter scale fail to solve the issue? Ummm... what issue?   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann <jeffl@cruzio.com>: Sep 22 10:08AM -0700 On Fri, 22 Sep 2017 07:55:03 -0400, bitrex   >On 09/20/2017 08:56 PM, Jeff Liebermann wrote: (...) >> refuses to allow a firmware downgrade.   >Thanks for the detailed reply! You can really brick Apple keyboads >during a firmware update whaaaaat?!   Firmware upgrade didn't brick the keyboard, but killed a few keys.   It's been a few years and the keyboards were recycled long ago. Before the upgrade, both wireless keyboards worked normally. Afterwards, the BT KBD would work, but several keys were dead. Different keys on each keyboard. I trashed one on my Mac Mini, while a customer trashed theirs on some other Mac. I vaguely recall the firmware version as 1.4, but that might be incorrect.   The problem was not the failed firmware upload, but rather that Apple does not allow firmware downgrades or reloading the same version that is installed. This is just plain stupid as I could have recovered the keyboard if either were allowed. I tried to find my postings to the Apple forum on the topic, but failed. The user replies were not very useful.   The reason that I mentioned it is that you will find Apple Aluminum BT wireless keyboards at thrift shops with a few defective keys. In many cases, new in the box. Everyone seems to assume that it's a mechanical or liquid problem with the keyboard mechanics. However, I believe it to be failed firmware upgrade problems similar to what I experienced.   Caveat Emptor.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Look165 <look165@numericable.fr>: Sep 22 08:21PM +0200 Generally, these devices are IR comunicating.     This needs an IR receiver on the PC.       bitrex a écrit :

Jeff Liebermann <jeffl@cruzio.com>: Sep 23 09:30AM -0700 On Fri, 22 Sep 2017 20:21:41 +0200, Look165 <look165@numericable.fr> wrote:   >Generally, these devices are IR comunicating. >This needs an IR receiver on the PC.   Huh? IrDA has been essentially dead for at least 10 years. I haven't seen a full size keyboard that uses IR for at least that long. Most everything these days uses some form of wireless to communicate.   Well, not totally dead. It is still possible to buy an IR keyboard today: <http://www.dsi-keyboards.com/product-category/keyboards/wireless-keyboards/ir-infrared-keyboards/>     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

Look165 <look165@numericable.fr>: Sep 23 06:35PM +0200 A question of cost efficiency and stock dumping.   IR is so simple to integrate.   ...And it uses "big batteries" !   Jeff Liebermann a écrit :

micky <NONONOmisc07@bigfoot.com>: Sep 23 11:01AM -0400 I'm thinking of installing a Gromaudio device that, if your car radio has a CD changer input jack, allows for USB input, AUX input from a cellphone, and for another $50 Bluetooth use of the cellphone through the car speakers and an add-on microphone (in addition to the first $150).   The most important feature for me is the USB input.   Do any of you know anything good or bad about Grom audio? Do any of you know a competitor you would recommend (instead?)?   For example, Crutchfield sells a similar device that is only $70 for everything (except the microphone and I can't even figure out how to plug a microphone in). But assuming a microphone would work, would you assume the one that sells for $200 is better than the one that sells for 70?     I've read as many reviews as I can find, but I wanted your opinions, and I wanted to let you know such things are available. I never heard of them before 4 days ago.   Their webpages will tell you if your car factory radio is compatible. They say they even retain the use of SWC, steering wheel controls.   There are one or two other companies that sell devices that have everything but the USB input, and I found something on ebay that had everything and was only $18. At that price it's worth trying it just in case it works, but based on the pictures, I don't think I could find one that fit my particular jack. Hmm. Now it says "Only 4 available" and the price has gone up to $20.

ss.chelsc@gmail.com: Sep 23 06:16AM -0700 SIL patterns invariably have one end with a square solder pad. This just helps you recognize which end is which when you turn your board over. I don't think it has a functional significance.

Foxs Mercantile <jdangus@att.net>: Sep 23 08:24AM -0500 > SIL patterns invariably have one end with a square solder pad.   The square pad is simply identification. Pin-1, Cathode, (+) etc.       -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com

Jeff Liebermann <jeffl@cruzio.com>: Sep 22 09:54AM -0700 >Too much here to respond to,   Sorry. I was in a hurry and didn't have time to be brief. Actually, I got interested in the topic and decided that it was worth expounding in detail. Enjoy.   >but also consider that ePaper displays don't >flicker. Even if you don't notice the flicker, moving your eyes creates >distortion while the ePaper display is fixed.   Flicker doesn't bother me much, so I don't notice it. The usual method of reducing LCD flicker is to use any vertical refresh rate that's not 60 Hz. However, on my desktop (Samsung SyncMaster 243T 1920x1200), I'm running 60 Hz because higher refresh rates (72 and 75Hz) result in a blurred image. I can't really see it with graphics, but with high contrast text, it's really obvious. I've also noticed this on some other monitors but not on all monitors.   I don't know about eye movement causing distortion. The problem is that on an LCD, each pixel is a combination of different color dots. <https://www.google.com/search?q=lcd+magnified&tbm=isch> To produce a white pixel, all the color dots need to be turned on resulting in a large and potentially blurry pixel. That's not a problem with e-paper, which only has to deal with turning one B&W dot on and off. <http://www.bit-101.com/blog/?p=2722> Try a magnifier on your devices and see for yourself. More on this (time permitting) if you're interested.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

rickman <gnuarm@gmail.com>: Sep 22 04:19PM -0400 Jeff Liebermann wrote on 9/22/2017 12:54 PM: > <http://www.bit-101.com/blog/?p=2722> > Try a magnifier on your devices and see for yourself. > More on this (time permitting) if you're interested.   Not sure what you mean when you say flicker doesn't bother you. You don't have to see the flicker for it to cause a problem. The point is your eyes don't adjust to a flickering screen as well as one that isn't flickering. Your eyes constantly readjusting is what makes them tired.   --   Rick C   Viewed the eclipse at Wintercrest Farms, on the centerline of totality since 1998

John-Del <ohger1s@gmail.com>: Sep 22 10:45AM -0700 On Wednesday, September 20, 2017 at 9:51:09 PM UTC-4, Ivan Vegvary wrote:   > Very little information on the web, what I would really like is a "DEFAULT RESET" function. I suppose I could put a switch in the battery circuit and do a manual shutoff. > Thanks for any ideas.   > Ivan Vegvary, Oregon       $16.80 on ebay including shipping: item 172863952489   Unless you can try a firmware (available, possible?), you're looking at a $16.80 dead end...

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