Home Improvement

wax eagle

1:39 PM

@KarlKatzke did you catch that he's a tenant?

Chris Cudmore

1:51 PM

@BMitch Which is why plate # should be a primary key!

BMitch

2:20 PM

@ChrisCudmore Should be, it was a WTF section of the podcast, complaining about the bad processes at the DMV.

wax eagle

2:35 PM

@ChrisCudmore we were really glad a couple of years ago that we weren't using our supposedly unique project numbers for primary keys in our database (we use a separate sequential ID). They decided that they could have several unique projects with the same corporate project number (has to do with separate client POs being issued on the same task).

also, just had an employee ask for "Mumbai" be added to our list of available countries.

Chris Cudmore

I'm a believer that key fields should be key, and unique. Your situation should probably have been solved via database redesign. I see all sorts of arguments as why not to make Social Security numbers P.K. -- all centered around flaws in the SS system and fraud/fake numbers. If I get a collision between you and bmitch, I should have the error immediately flagged and notify you both of a collision. I should not design the system to permit erroneous data.

But Mumbai ... that's funny.

wax eagle

@ChrisCudmore perhaps, and we have several other design flaws that we're living with because they are more work than they are worth to fix...but the problem would be changing our app in place with a little business disruption as possible...

theory, meet reality, you're not going to like each other. :)

@ChrisCudmore also, if we redesigned our entire system every time TVA decided to change their billing requirements, we'd need 100 devs instead of just 3 :)

Chris Cudmore

It sounds like billing is too tightly bound to projects.

Over all, I agree with you. I'd probably do some sort of weak entity table to hold the extra info, and bind onto that. It's the quickest fix.

wax eagle

@ChrisCudmore we have dependencies everywhere

Chris Cudmore

2:52 PM

Don't we all.

Matthew PK

@ChrisCudmore which is why I've always been a fan of surrogate keys

The row should be identified by the key, the whole key and nothing but the key, so help me Codd.

wax eagle

@MatthewPK I should really go back and read my database book now that I actually use this stuff, just to find out how well/bad we are doing

not that it means anything because I don't have control over design for the most part (i have input, but not control :()

Matthew PK

@waxeagle sounds like the plight of most engineers :D

wax eagle

3:08 PM

@MatthewPK school is all about learning the theory, work is all about learning how the theory breaks down when you have to actually use it and learning how to hack around it :)

Matthew PK

@waxeagle yeah, I know plenty of "engineers" who can't apply patterns at all, and plenty who will bitch about design mandates without being able to implement something better.... The main focus should often be sustainability of the project... sometimes a hack is ok, but for a continuously integrated project it is often a major obstacle later on

imho

on a completely unrelated note! .... Two days ago my power went out, and now the digital clock on my microwave is ticking a minute every 46 seconds....

??? wtf

wax eagle

@MatthewPK lol, sounds like it's clock chip was damaged :) might want to check make sure the seconds still count correctly when you cook something :|

Matthew PK

good thinking, I hadn't tried that

Niall C.

@MatthewPK Does it have a 50Hz/60Hz setting?

Matthew PK

dunno... but I haven't touched anything on it

wax eagle

3:15 PM

can a power surge change the oscillation of a crystal? (do clocks still use crystals?)

The Evil Greebo

@MatthewPK Probably someone just hacked in 60 seconds on the clock

Chris Cudmore

@waxeagle Yes. Even your computer has a crystal in the PLL (timing) chip.

wax eagle

@ChrisCudmore cool. still mostly quartz?

Chris Cudmore

"In all performances cases, crystal controlled oscillators are better behaved than the semiconductor- and LC-based alternatives. They tend to be more stable, more repeatable, have fewer and lower harmonics and lower noise than all the alternatives in their cost-band. This in part explains their huge popularity in low-cost and computer-controlled (i.e. PLL and synthesizer-based) VFOs."

Variable-frequency oscillator

A variable frequency oscillator (VFO) in electronics is an oscillator whose frequency can be tuned (i.e. varied) over some range. It is a necessary component in any tunable radio receiver or transmitter that works by the superheterodyne principle, and controls the frequency to which the apparatus is tuned. Purpose In a simple superhet radio receiver, the incoming radio frequency signal (at frequency f_{IN}) from the antenna is mixed with the VFO output signal tuned to f_{LO}, producing an intermediate frequency (IF) signal that can be processed downstream to extract the modulated informat...

I have no idea if it's still quartz.

Matthew PK

A few years ago we used a simple diffraction grating, a piezo and a screw to reliably vary and tune the frequency of laser diodes

within a specific range, of course

the piezo was driven solely by ICs

Niall C.

3:28 PM

A microwave is probably using either mains crossings or a 32.768kHz watch crystal to measure time

Chris Cudmore

a piezo is a crystal isn't it?

Niall C.

@ChrisCudmore yes

Matthew PK

Not in the sense of an oscillator

and not all of them are

BMitch

1

Q: Where can I find parts for attic pulldown stairs?

I need two rollers replaced in my attic loft pull down staircase - the big ones on the picture. These drums have tension spring inside that helps to pull the stairs up and down. The mechanism is quite similar to sectional garage doors but garage door contractors I have called would not even go p...

5

Q: What kind of contractor would I need to service or replace pull down attic stairs?

I have attic loft with pull down stairs access to it and I need it either serviced or replaced with a new rope system. Can you advice what kind of contractor I'd need for this? As you can see on the picture below it is not your basic attic ladder but quote sophisticated garage like pull down st...

attic stairs contractors

I'm guessing the last answer didn't really solve his problem, should this be considered a dup?

They are different questions trying to solve the same problem

1

Q: Do the guidelines for holes in joists apply to band joists?

This question have a great answer with all the guidelines for drilling holes in joists. The question: Are the guidelines the same for band joists? A bit of context: I'd like to add an exterior outlet for my central vaccuum cleaner and the shortest path is through the band joist. But I'm not sur...

code-compliance joists hole

exterior outlet to his central vacuum??? Is he going to vacuum his lawn?

wax eagle

@BMitch maybe his porch?

also, i want a central vacuum

BMitch

3:41 PM

I want to see the lawn vacuumed :)

@waxeagle I think they're overrated, all the effort saved not dragging around the vacuum cleaner is replaced by dragging around a big hose.

Matthew PK

exterior central vacuum plugs are common

and I agree that central vacuums are overrated

but exterior outlets are a potential hazard

Chris Cudmore

I think he wants one in or near the garage.

Matthew PK

a few months ago we had some serious burshfires here, and some million dollar homes burned down

wax eagle

@BMitch good point

Matthew PK

one of them, a concrete block house with a cement tile roof, burned down because the heat melted an exterior vacuum socket, causing the machine to turn on... which then sucked embers into the house.

BMitch

3:45 PM

@MatthewPK Yowza, that sucks

Matthew PK

@BMitch I have seen my mother vacuum a section of her lawn before

wax eagle

@MatthewPK yikes

Chris Cudmore

@MatthewPK Really? I thought there was a physical switch in the outlets that went on when you inserted the hose.

BMitch

My family's neighbor is going nuts, she goes out with a dust pan to cleanup grass clippings that blow over to her driveway

Chris Cudmore

I've also seen them with two low-voltage brass nipples that are electrically connected with a metal band on the hose.

Matthew PK

3:47 PM

@ChrisCudmore It's two low-voltage conductors, the hose is just a switch... melt the outlet and they got bridged.

BMitch

@ChrisCudmore I've seen the electrical style, all it takes is a short

Chris Cudmore

@MatthewPK That makes sense.

Chris Cudmore

5:01 PM

0

Q: How do I wire this kitchen fluorescent ceiling fixture?

I bought a new Home Depot kitchen ceiling fixture but am not sure of the proper way to install it. The fixture itself has black, white, and bare copper. The ceiling wiring is red and gray(white?). What goes to where?

wiring lighting

Is gray wiring normal? Could it be apartment single-strand wiring?

Chris Cudmore

5:12 PM

Parenting Win:

-2

Q: Is this considered child abuse

First, my mom never hits me; I want to be clear on that. My brother 13, and I, 15 got into a fight at McDonalds. We threw ketchup at each other and I accidentally got some on on a nearby woman. My mother had to reimburse the woman for the damage. My mother freaked out and humiliated us in McDona...

teen punishment

BMitch

Yes, McDonalds is a form of child abuse. — DA01 Jan 6 at 22:14

Karl Katzke

6:06 PM

@waxeagle He posted that he was a tenant I think after my answer. Which surprises me none -- the roof on the house we're renting in Houston is just as bad.

wax eagle

@KarlKatzke gotcha

Karl Katzke

@ChrisCudmore Grey is probably the neutral. And @BMitch and I have weighed in, but you actually can't omit the ground when you're wiring a fluorescent fixture, and it's really bad advice to advise someone that you can.

Chris Cudmore

If the code was such at the time the original was installed, then it can be replaced without upgrading the wiring.

Karl Katzke

Actually, it can't because the ballast won't start without the fixture grounded.

Most ballasts built this year will have that 'feature'

I found that out the hard way last weekend.

The symptom you'll see is that the entire fixture will show up live to a non-contact voltage tester when you switch it on.

I found that the ground at the other end of the wire running to that fixture had been snipped short inside the switch box...

Confused the hell out of me and I'd thought I'd gotten a bad unit. Then I (gasp) read the manual.

Chris Cudmore

@KarlKatzke You read the manual? -500 rep right there.

2

Karl Katzke

6:19 PM

I know, I know. I hate to admit it. :-P But it said in big bold letters that the fixture has to be grounded for the ballast to work.

Which made me get out my multimeter and find out that the ground wire I'd connected didn't work.

Chris Cudmore

Oh, If it's in bold it's ok.

You're allowed to glance at it. Just not actually read it.

Karl Katzke

Yeah, it was in the "warnings" section on the cover. I didn't actually open the manual, if it helps any.

And I had to open the trash can lid to read it.

Chris Cudmore

The problem is, that most of the warnings section is crap. "Do not eat silica gel", "Do not stop spinning blade with your hands" and stuff like that. It's usually the first section I ignore.

They really should have two warnings sections - "Lawyer warnings" and "Really Important Warnings particular to this project"

3

Like a chainsaw would have "Do not stop chain with hand" as a lawyer warning. "The entire saw can kick back, particularly when sawing knotty wood" would be something really useful to know.

Of course, a Chainsaw should also have "This is the most dangerous tool you will ever own!" on it.

Karl Katzke

No, that title's reserved for a toe kick saw.

wax eagle

@KarlKatzke that looks dangerous

Karl Katzke

6:34 PM

yeah, they have a bad habit of running astray. I think they call it a "toe kick" saw because you're likely to lose a toe.

Chris Cudmore

The GIS for that has some nice pictures of stitches.

I guess if there's any binding, the whole saw will torque out and get medieval.

Karl Katzke

Yeah. Sort of like a chainsaw, but with a higher torque motor and less leverage on the handles.

Chris Cudmore

We're pretty used to torque on a tool in the hammer swing directions, but that's on another plane altogether. (ie, it would be -z, rather that +x)

The Evil Greebo

@ChrisCudmore Manuals are used to prop up saw horse legs.

(he said, having just spent 15 mins reading NUnit's documentation on TestCaseSourceAttribute)

Chris Cudmore

Testing! Testing is for those who don't do it right the first time. A manual for a test framework is automatic revocation of your man card.

The Evil Greebo

6:54 PM

Yes, you've said so before.

BMitch

10:41 PM

@vebjornljosa I'm confused about your comment, this didn't look like an answer to me: diy.stackexchange.com/questions/18608/…

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