Root Access

Bob

00:02

gotta say, though, those buttons look ... pretty messy :P

Canadian Luke

That's the default, centered aligned with the image to the left. I made everything big for the Surface Pros that some of the Administration Staff have

Otherwise, I'd prefer smaller, and no pictures

Bob

@CanadianLuke could at least left-align them :P

or left-align the icons

also the bottom left button doesn't look centred

Canadian Luke

Hmmm

Trying the different options in Visual Studio, none seem to make them look good

Michael Frank

Yea, those labels are all at rather awkward positions. :P

Canadian Luke

If I left-align them, and have the images on the right, that's the closest to semi-normal, but still weird

How's that?

FML Cat

00:18

You guys are smart, what does the DT part of a 4PDT switch mean?

Canadian Luke

Double-Tap

FML Cat

Cool! Thanks

Canadian Luke

... I have no idea

FML Cat

I knew you'd know :-D

Bob

@FMLCat double throw

normally SPST, SPDT, DPST, DPDT... 4P is a bit odd

DT just means you can close separate circuits in either position of the switch

ST means you can only close a circuit in one position; the other position is unpowered always

FML Cat

00:22

@Bob Cool. I think I need a DPDT minimum but Maplin has a cheap 4PDT and all the other options are SP I think

Bob

@FMLCat you'd only need >SP if you need to keep two circuits independent from each other but both activated by the same switch position

I think more Ps than you need is usually fine but you might want to check the current rating

FML Cat

Basically I have a dumb ammeter that can only measure current across an external shunt in one direction. So I need a switch to switch the polarity of the +/- pins

@Bob It's just a voltage measurement, current flow will be zero (or immeasurably negligible)

Bob

ah

so you'd need a DT at a minimum, but idk if you really need more than SP... 4P shouldn't hurt

also switch nomenclature has always confused me

Journeyman Geek

dual throw.

FML Cat

@Bob Well there's two lines coming off the shunt so I'd need DP I'd suspect

Journeyman Geek

00:28

@FMLCat when in doubt, and its cheap, the continuity tester is your friend

FML Cat

Journeyman Geek

hmm

Bob

@JourneymanGeek double is more conventional :P

Journeyman Geek

A | A
N | N
B | B

FML Cat

learn.sparkfun.com/tutorials/switch-basics/…

This explained a lot

Journeyman Geek

00:31

@FMLCat its worth thinking of it this way - basically you have position A and B. N is common. each 'side' is seperate.

FML Cat

Urgh then there's On-On On-Off On-Off-On On-(Off) (On)-Off crap too

@JourneymanGeek I don't want no commoners!

Journeyman Geek

so assuming N isn't tied together, what you need to do is connect + to A and - to N on one side, and N to + and B to - on the other.

@FMLCat you want (k)nobs?

FML Cat

@JourneymanGeek Now you've lost me

@JourneymanGeek No, just a simple rocker will do

Journeyman Geek

@FMLCat ya see how that switch has 6 pins?

FML Cat

Eh I figured it out

Need a DPDT but 4P won't hurt if I leave the other two P's disconnected. And they're all the same price anyway

Of course having a non-dumb ammeter would negate this problem, despite this one trying to be "smart" and having excessive features I don't need, it can't measure bidirectional current -_-

This is the crap I have

Bob

00:39

wpdev.uservoice.com/forums/110705-universal-windows-platform/…

votes pls :D

(also, @allquixotic ^ ... replacement for named pipes? POSIX-y Windows? :D)

Canadian Luke

@Bob Instructions unclear; reported to mods instead

FML Cat

Bob's outsmarted me

Bob

o.O

Canadian Luke

OK, issue with .Net Core - it won't launch the Explorer window for the Printers folder

Bob

@CanadianLuke Hm?

How are you launching it?

Canadian Luke

00:50

On a Windows 10 system (brand new), I ran the program... Clicked the button to open the Printers folder, and now I'm getting an error that the library can't be found

The .exe, all by itself, on another system

Bob

@CanadianLuke Yea, uh... I just remembered Core doesn't support WPF/WinForms.

Canadian Luke

....

Bob

sorry!

completely forgot -_-

actually I'm wondering how you got to a button in the first place

Canadian Luke

Wait... I remember I didn't get the Core part running... It's targeting .Net 4.0

Journeyman Geek

meta.stackexchange.com/questions/306737/… coming soon if you don't have adblock.

FML Cat

00:52

Gah how hard can it be to find a standalone ammeter that can measure bidirectional current... geez. Just about every multimeter does it by default

Journeyman Geek

"standalone" there's your problem!

FML Cat

@JourneymanGeek It's kinda hard to keep hold of a probe-based multimeter while riding a motorcycle, not to mention most don't support 100A current measurements without an external shunt and manual maths

Journeyman Geek

2 multimeters? ;p

Canadian Luke

OK, error was my fault... If I hard-code the `C:\Windows` folder, then it works.

I'm going home now

FML Cat

@JourneymanGeek Or two standalone meters, which is excessive but does work... I had considered it...

Journeyman Geek

01:00

hmm

or diodes, leds to show direction (which may also work as diodes - but eh, max voltage) and one multimeter.

Bob

@PolyGeo Many GIS developers are looking for a soulmate, so by that logic "hot singles in your area" would be on-topic, too. — Federico Poloni Nov 25 '16 at 13:44

@JourneymanGeek Also I thought SU already had ads

Journeyman Geek

@Bob apparently not affiliate ads - like for products, or something.

I donno. I adblock ._.

FML Cat

Maybe I should build some sort of current divider, or something

@JourneymanGeek Problem with diodes is this thing relies on miniscule voltages (75mV at 100A, so microvolts at low current) and AFAIK you can't get diodes to switch on microvolts

Heck now that I think about it all laptop batteries have this sorta circuitry built in

Bob

01:21

latest xkcd is so true... I still haven't found the perfect bag :P

"This one is perfect in every way, except that for some reason it's woven from a tungsten mesh, so it weighs 85 pounds and I'll need to carry it around on a hand cart." "That seems like a bad--" "BUT IT HAS THE PERFECT POCKET ARRANGEMENT!"

@JourneymanGeek but they're saying they're expanding it to more sites... I thought trilogy already had them

FML Cat

@Bob Swap laptop and backpack and you've got me

Bob

@FMLCat en.wikipedia.org/wiki/Precision_rectifier? idk electronics :P

@FMLCat digitaldiy.io/articles/electronics/general/… 50mV...

> Using a MOSFET in place of a diode provides a resistive channel so that voltage drop is proportional to current and can be much lower than for a diode.

=> electronics.stackexchange.com/a/38776/34550

proportional to current, you say..?

> How much this is depends on the FET chosen but 10 milliohms FETs are relatibely common. At 10 mOhm and 1A you get only 10 milli-Volt drop.

@FMLCat Wait are you actually sending 100A over the diodes?

Hm. No. That'd be over the shunt.

*shrug* what's the actual measured current?

FML Cat

@Bob Anywhere from -10 to +100A

Bob

@FMLCat Sorry, I meant ... uh. I have no idea what's going on actually :P

@FMLCat got an example circuit diagram?

FML Cat

@Bob Current going into and out of a motorcycle starter battery

Michael Frank

01:32

@Bob This is 100% true for me at the moment...

Bob

@FMLCat ya, but what's the current going to the ammeter (i.e. not the shunt)?

taking this example allaboutcircuits.com/textbook/direct-current/chpt-8/…

the current going to the 'movement', I suppose

FML Cat

@Bob Nothing

The ammeter measures current by measuring voltage across the shunt

Bob

@FMLCat well, wouldn't that depend on the input resistance of your voltmeter then?

FML Cat

@Bob Well it's a standalone device that uses a voltmeter function to display current but for all intents and purposes in the input resistance is/should be infinite

Bob

lemme just try to remember the math...

@FMLCat IIRC ~10MOhm is common

But yea. The current is probably low enough you could just hook up one of those mosfets

it'd still affect the reading, and the voltage drop depends on current through it, but it's probably negligible compared to the input resistance

FML Cat

01:41

Wonder if it'd be easier to hack the firmware of the measurement device

allquixotic

@Bob It's down to two: the one with the Class 1 range and the one with ANC -- wait, that other one has 40 hours of battery life! Ugh. Do I even want new BT headphones? Maybe I should be looking at wireless non-BT headphones again. OK, starting over.

Journeyman Geek

or wired headphones ;p

FML Cat

This one's dodgy enough anyway since it has no reset/recalibrate button and measures a constant phantom current of 0.33A

Bob

@allquixotic but... you've got two examples already with class 1 + ANC :P (three, if you count the discarded beats)

@FMLCat what value shunt are you using? and do you have the specs for your voltmeter?

allquixotic

@Bob I own zero pair with class 1 + ANC currently, and only had the Beats for a while because they hurt my ears

Bob

01:43

@allquixotic thought you ordered the PXC?

allquixotic

That's a general problem with many things I buy. I want features A, B, C, D, E and F, and every product is missing one or more of them

Bob

(still not-too-subtly suggesting the backbeat pro 2 here :D)

allquixotic

@Bob I did, but they're not here yet! :P

Journeyman Geek

@allquixotic does ANC make sense for normal use? I always felt they were more useful in aircraft.

FML Cat

@Bob 75mV at 100A

allquixotic

01:43

and I wasn't saying I need yet another pair; I was just applying the message of that xkcd to my BT headphones quest

FML Cat

It's one of these things

amazon.co.uk/…

Bob

@JourneymanGeek I've used mine for lawn mowing and power tools (hole saws, etc)... it's great

@FMLCat ah. lemme math that

allquixotic

@JourneymanGeek IMO it makes perfect sense... I dislike hearing people talk about stuff while I'm trying to work, and ANC is great at making people shut up (at least from my own perspective)

Journeyman Geek

0_0

maybe its gotten a lot better. I found active noise cancelllation is good for drony noises.

allquixotic

also great when occasionally commuting by train... the engineer often waits until the train is right on top of us to blow the horn announcing his arrival, killing our ears

Bob

01:45

0.00075 Ohm

allquixotic

standing on the platform is much more comfortable with ANCs on

FML Cat

@Bob Yeah, that

Journeyman Geek

passive noise cancellation and bigass cans almost work better for shutting people up

Bob

@JourneymanGeek modern ANC is more active than that

Journeyman Geek

ah, its been a while I guess

Bob

01:46

it's not quite perfect but there's a noticeable drop in noise

allquixotic

and if a saw is going "NYEEEEEEER!!!!" the ANCs almost perfectly cancel it out with a "!!!!REEEEEEEEEYN"

Bob

@FMLCat Do you have one of those with you right now?

FML Cat

1 hour ago, by FML Cat

Journeyman Geek

saws... are a perfect use case.

Bob

@FMLCat can you measure the input resistance? electronics.stackexchange.com/questions/13047/…

@FMLCat ...imblind

Journeyman Geek

01:48

but .... why are there saws where you work? 0_0

starts suspecting @allquixotic works for the TLA again.

allquixotic

@JourneymanGeek there are saws everywhere

Journeyman Geek

0_0

allquixotic

I regularly go to work with a running saw on my car's dashboard

my coworker saws his carrots in half for lunch

Journeyman Geek

clearly you work for the VSA...

"Very Strange/Saw Agency"

allquixotic

!!doge saw,saw,saw,saw,saw,saw,saw,saw

ChatBot John Cavil

01:50

        wow
                       many saw
such saw
            much saw
                          very saw
so saw
              very saw
                           many saw
so saw

Journeyman Geek

or maybe the National Saw Agency. "Cutting down america's trees to size since 1779"

potatoman

Hello!

allquixotic

1776?

potatoman

I have a question.

Is downvote abuse on superuser a common thing?

Journeyman Geek

@allquixotic those chaotic times were why the agency was founded

FML Cat

01:51

@Bob Weird. It says 1.3 in 200mOhm mode and out of range in 20mOhm mode

Journeyman Geek

@potatoman not really

potatoman

Well.

I just had almost all my posts (Some from years ago)

allquixotic

@potatoman that's something to search meta.superuser.com for, really, or ask a question if you honestly think it's not a duplicate

potatoman

downvoted all in one go

Bob

@FMLCat Assuming it's 10MOhm on the voltmeter, for 75mV you're looking at something like 7.5uA though the voltmeter.

allquixotic

01:51

@potatoman if you get more than 3 downvotes from the same user, they'll automatically be refunded as "serial downvoting"

Bob

@potatoman Yea that'd be serial downvoting. It'll probably be auto-reversed. If that doesn't happen in a few days, email the SE team.

potatoman

Want pics?

Bob

It's rare but it does happen as isolated cases of users acting up.

FML Cat

@potatoman TWSS

Journeyman Geek

we can take a rough look at your account but I think people actually might be DVing your questions case they need some bulking up

Bob

01:52

@FMLCat You should be able to make a bridge rectifier out of that mosfet that guy posted.

potatoman

Kinda unlikely

Since they were downvoting posts from years ago

All within MINUTES of each other

So I lost a LOT of points

45 -> 32

FML Cat

@Bob Nice

Ben N

Indeed, I see your reputation history

Bob

@potatoman Yea, don't worry about it - it'll be auto-reversed.

Ben N

If it's serial downvoting, it will be reversed within a day or so

allquixotic

01:53

that's not a lot, to be honest... but if that's from the same user, that's still enough for automatic serial downvoting reversal logic to kick in

potatoman

So if it doesn't get fixed.

Who should I contact?

Bob

@allquixotic It's enough to be a deliberate attack.

@potatoman Contact us link down the bottom, SE team.

Wait a couple days first.

Site mods can't do anything about voting.

potatoman

Thanks everyone for the help

See ya!

FML Cat

@Bob That's what happens when you hire a dog to be your site mod

Bob

@FMLCat electronics.stackexchange.com/a/38776/34550, taking the 100 mOhm Rdson example, 0.1V per A, 7.5uA = 0.75uV drop. Assuming it works at currents that low, anyway.

Journeyman Geek

01:56

@FMLCat our abilities on that are limited. We can't see who voted on a post or undo those.

FML Cat

@Bob Which would throw the measurement off by 0.001A, which I guess is... acceptable

@JourneymanGeek Maybe if you had opposable thumbs instead of paws?

Journeyman Geek

naw, normal human mods typing with their normal human hands have the same restricictions

FML Cat

How would you know, have you ever tried being one?

Journeyman Geek

naw, but there's no "mod-dog" flag

FML Cat

That's what they want you to think

Bob

02:01

@FMLCat The hard part is probably finding a mosfet with a low enough threshold voltage

Journeyman Geek

(granted, there's a ton of mods with dog avas, and less with cat avas)

Bob

@FMLCat what's the lowest current you might measure?

FML Cat

@Bob 0.02A? Practically speaking 0.1A resolution would be enough

Bob

@FMLCat Ouch... that's probably not doable with a mosfet

even 1A is hard

that's only 0.75mV

from what I'm seeing it's hard to find a mosfet with < 10mV Vgs threshold

potatoman

Sorry, it's me again.

Well.

It's serial downvoting

Thankfully, 3 UTC is coming soon

1 HR

FML Cat

02:08

@Bob Isn't that why we put a PA in the circuit?

Bob

@FMLCat I mean, you'll get a greater resolution than that, but with a mosfet the measurement would cut out entirely somewhere around... 10A absolute? 5A if you're lucky?

@FMLCat PA?

FML Cat

The amplifier bit

Bob

@FMLCat Wait. Where's the amplifier? o.O

FML Cat

The thing you linked to earlier? I am confuse

Bob

@FMLCat erm... I don't think I linked to anything with an amplifier.

Michael Frank

02:13

Huh... Grammarly is creating a huge amount of blank space between the last message in chat and the message box. o.O

Bob

hmmmmmm

@FMLCat wait, you're dealing with a 12V (24V?) battery, right?

I think (I know nothing about mosfets apart from today) you can just supply a higher voltage to gate-source and it should let your <75mV pass through gate-drain

s/gate-drain/source-drain/

@FMLCat Ok. hook up gate-source directly to the battery (with protection against voltage spikes). hook up source-drain to the voltmeter.

polarity is iffy

FML Cat

02:35

@Bob That's what I thought you were getting at earlier

Bob

@FMLCat Wait. Have we had this conversation before? (@JourneymanGeek)

@FMLCat mouser.com/ds/2/389/en.DM00224698-1223617.pdf

though that's probably way overkill

Journeyman Geek

Oddly enough... no

Bob

02:53

@FMLCat this looks good mouser.com/ds/2/427/sqj202ep-935238.pdf

you should be able to hook up both directions on it

+75mV => meter => drain => source => 0V, and +battery-V => gate => source => 0V

FatalBulletHit

@BenN If you are curious what I needed this for: stackoverflow.com/a/48676531/9248774 :)

Bob

and -75mV => source => drain => meter (flipped) => 0V, and -battery-V => source => gate => 0V

add some overvoltage protection on the two gate => source connections and I think that should work

@FMLCat ^, au.mouser.com/ProductDetail/Vishay-Siliconix/SQJ202EP-T1_GE3

FatalBulletHit

@Burgi figured that... :D

Bob

you should be able to protect the gate with electronics.stackexchange.com/questions/233394/…, I guess?

wait no a zener is a bad idea here

maybe a TVS diode?

FML Cat

@Bob beats me, I'll still know nothing about mosfets tomorrow.

Bob

05:04

hm

I have a 2700 page 100 MB pdf

halp

Journeyman Geek

05:42

no one can help you now.

potatoman

PSone SCPH-102 - Shorting IC CXD2941R

►

shorting a PS1

Bob

@JourneymanGeek the saladcase (:D) hurts my eyes: superuser.com/a/1292439/117590

oh, guy's German

potatoman

Oh

Bob

@Greg It's because any war between Alaska and Siberia would necessarily be a cold war. — tchrist yesterday

I swear the entire question was set up for just that joke :P

Journeyman Geek

06:08

@Bob heh. I just got a lxc container being set up. Might try experimenting with moving some services over to that (wanting to play with bitwarden @allquixotic 's fault, but throwing a third dbms on a physical system feels odd)

Bob

06:32

@JourneymanGeek you mean lxd, right?

please tell me you're not using raw lxc :P

Journeyman Geek

lxd

....

github.com/Microsoft/mssql-docker/issues/13

bleeeeeh

bwDraco

Your brain needs oxygen to realize anything, including the fact that it's not getting enough oxygen. In short, biology makes it very hard for a person to realize that they need more oxygen. The brain's not equipped with a low-oxygen-sensor, it just stops working. Fairly rapidly, too. — aroth Jul 24 '16 at 0:54

> The brain's not equipped with a low-oxygen-sensor, it just stops working.

lol

Bob

@JourneymanGeek ?

Journeyman Geek

@Bob guess what my server uses ;p

Oh!

more or less MSSQL won't run on a zfs filesystem

so I need to get an ext4 filesystem for /var/opt/mssql

Bob

06:53

@JourneymanGeek ...that doesn't sound right

Journeyman Geek

@Bob mostly useless error message and that's literally the suggested fix

Bob

@JourneymanGeek still sounds wonky as all hell

in a "wtf is mssql doing" way

Journeyman Geek

its mssql on linux

;p

Bob

@JourneymanGeek and? so? it's still wonky as all hell

Journeyman Geek

Yes it is!

Bob

06:57

wait. are you using a docker image?

Journeyman Geek

nope!

Bob

ok

Journeyman Geek

just the default ubuntu lxd image

pastebin.com/A4JTsUMK

working notes

Bob

zfs create -s -V 10G -o volblocksize=4k pool/disks/sqlserver

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