1049 stories

Brussels tried to blame it on him being a "bad guy", but Angola quickly dismissed that argument, insisting that Brussels is more than whatever labels he's allowed to be applied to himself.

archive - contact - sexy exciting merchandise - search - about
July 22nd, 2014next


This Wednesday (tomorrow!) the final issue of The Midas Flesh comes out! You can read a preview here, and catch up with all you missed at midasflesh.com!

– Ryan

Read the whole story
1 minute ago
"Those poor sharks must be stressed and agitated"
Earth, Sol system, Western spiral arm
Share this story
1 public comment
7 hours ago
alt-text: Angola Maldives broke free and managed to lecture his arch-nemesis, Brussels Samoa, on proper sharkkeeping. Also he stopped his space lasers from melting the Earth's crust. I forgot to mention that part but it was going on the whole time.
Rio de Janeiro, Brasil

Researchers Test Developer Biometrics To Predict Buggy Code

1 Comment

rjmarvin writes: Microsoft Research is testing a new method for predicting errors and bugs while developers write code: biometrics. By measuring a developer's eye movements, physical and mental characteristics as they code, the researchers tracked alertness and stress levels to predict the difficulty of a given task with respect to the coder's abilities. In a paper entitled "Using Psycho-Physiological Measures to Assess Task Difficulty in Software Development," the researchers summarized how they strapped an eye tracker, an electrodermal sensor and an EEG sensor to 15 developers as they programmed for various tasks. Biometrics predicted task difficulty for a new developer 64.99% of the time. For a subsequent tasks with the same developer, the researchers found biometrics to be 84.38% accurate. They suggest using the information to mark places in code that developers find particularly difficult, and then reviewing or refactoring those sections later.

Read the whole story
4 hours ago
they can detect my eyes rolling when I run into crappy code? wow.
Earth, Sol system, Western spiral arm
Share this story

Netflix Reduces Physical-Disc Processing, Keeps Prices the Same

1 Comment
Nom du Keyboard writes: After seeing a drop in my DVD service from Netflix I got a customer service representative tonight to confirm that Netflix has ceased processing DVD returns on Saturdays nationwide. And that they did this without notifying their customers, or reducing prices to compensate for the reduced service. Given that the DVD selection still far outstrips their streaming selection, this may be news to others like myself who don't find streaming an adequate replacement for plastic discs. My experience up until recently, unlike Netflix's promise of a 1-3 day turnaround at their end which gives them lots of wiggle room to degrade service even further, had been of mailing in a DVD on day one, having them receive it and mail out my next selection on day two, and receiving it on day three. Now with them only working 5 days and many U.S. Post Office holidays, they're still getting the same money for significantly less. The Netflix shipping FAQ confirms the change, and a spokesperson said, "Saturdays have been low volume ship days for us."
Read the whole story
6 hours ago
one less reason to ever turn my netflix subscription back on, I guess.
Earth, Sol system, Western spiral arm
Share this story

Kenmore 158: MOSFET vs. Rectified 120 VAC

1 Comment

Kenmore 158: MOSFET vs. Rectified 120 VAC

This arrangement actually worked:

Kenmore 158 - FW bridge MOSFET test

Kenmore 158 – FW bridge MOSFET test

At least until I blew out the MOSFET, which is about what I expected. It’s screwed to that randomly selected heatsink, with a dab of thermal compound underneath.

Incoming AC from an isolated variable transformer (basically, an isolated Variac) goes to a bridge rectifier. Rectified output: positive to the motor, motor to MOSFET drain, MOSFET source to negative.

MOSFET gate from bench supply positive and supply negative to source.

Hall effect current probe clamped around the motor current path.

The MOSFET was an IRF610: 200 V / 3.3 A. That’s under-rated for what I was doing, but I had a bunch of ‘em.

I actually worked up to that mess, starting with the bare motor on the bench running from the 50 VDC supply. That sufficed to show that you can, in fact, control the motor speed by twiddling the gate voltage to regulate the current going into the motor. It also showed that a universal-wound motor’s square-law positive feedback loop will definitely require careful tuning; think of an unstable fly-by-wire airplane and you’ve got the general idea.

In any event, flushed with success, I ignored the safe operating area graph (from the Vishay datasheet):

IRF610 - Safe Operating Area

IRF610 – Safe Operating Area

Drain current over half an amp at 160-ish peak volts (from rectified 120 VAC) will kill the MOSFET unless you apply it as short single pulses, not repetitive 120 Hz hammerblows.

I also ignored the transfer characteristics graph:

IRF610 - Typical Transfer Characteristics

IRF610 – Typical Transfer Characteristics

The curve starting at the lower left should be labeled 25 °C and the other should be 150 °C. The key point is that they cross around VGS = 6.5 V, where IDS = 2 A. Below that point, the MOSFET conducts more current as it heats up… which means that if a small part of the die heats up, it will conduct more current, heat up even more, and eventually burn through.

Yes, MOSFETs can suffer thermal runaway, too.

The motor draws about half an amp while driving the sewing machine, which suggests the gate voltage will be around 5 V. In round numbers, it was 5.5 to 6 V as I twiddled the knob to maintain a constant speed.

At half an amp, the MOSFET dissipated anywhere from a bit under 1 W (from RDS(on) = 1.5 Ω to well over 25 W (while trying to maintain headway with friction on the handwheel). I ran out of fingers to record the numbers, but dropping 10 to 20 V across the MOSFET seemed typical and that turns into 5 to 10 W.

It eventually failed shorted and the sewing machine revved up to full speed. Sic transit gloria mundi.

In any event, I think the only way to have a transistor survive that sort of abuse is to start with one so grossly over-rated that it can handle a few amps at 200 V without sweating. It might actually be easier to get an ordinary NPN transistor with such ratings; using a hockey puck IGBT or some such seems like overkill.

Eks probably has a box full of the things …

Read the whole story
8 hours ago
what, no picture of the blown-up mosfet?
Earth, Sol system, Western spiral arm
Share this story

women-owned worker coops & the fight against the feminization of poverty

1 Share
Sarah McKinley and Violeta Duncan for Community Wealth: Worker Cooperatives Address Low-Wage Work and the Feminization of Poverty.
Women of color working low-wage jobs must often navigate unregulated work conditions, as much of their work is domestic labor—caregiving, house cleaning, child care—an industry that, historically, is not only low-paid but also exploitative. The National Domestic Workers Alliance (NDWA), a 10,000 membership-based organization for nannies, housecleaners, and caregivers, describes, in its 2012 Home Economics: The Invisible and Unregulated World of Domestic Work [PDF] report, the substandard conditions of domestic work, including lack of employment benefits, meager wages, exposure to toxic chemicals, and physical abuse.

Such unhealthy work environments and insufficient pay have led a number of these low-wage women to take matters in to their own hands. Many have formed women-owned worker cooperatives that ensure good pay and healthy working conditions, help women overcome the isolation and vulnerability of domestic work, and empower women to build wealth for themselves, their families, and their communities.

Women-owned, women-run worker co-ops featured in the article include: Other women-owned, women-run co-ops in the United States: Bonus reading material: Previously on MeFi:
Read the whole story
Share this story

Gender Rolls

1 Comment

New Comic!

My gender expression is varied enough day to day that sometimes I feel like it would be easier if the decision was just taken out of my hands.

Transcript below:


Daily Gender Check:

Roll Three:

Roll 1d8

1 – Agender

2 – Genderqueer

3 – Trans

4 – Genderfluid

5 – Cis

6 – Non-Binary

7 – Questioning

8 – Bigender

Roll 1d10

1 – Dapper

2 – Femmetype

3 – Twinky

4 – Sophisticate

5 – Androgynous

6 – Leather

7 – Flexible

9 – Queerdo

10 – Nonconforming

Roll 1d12

1 – Princex

2 – Dragon

3 – Beefcake

4 – Shortcake

5 – Dudebro

6 – Gentleperson

7 – Cumberbatch

8 – Butch

9 – Bear

10 – Dandy

11 – Otter

12 – Queen

A: What did you get today?

B: Genderqueer femmetype dudebro

A: Tough one.

B: Nah, I’m going to totally rock it. You?

A: Agender sophisticate dragon.

b: Nice.

Read the whole story
13 hours ago
hee hee, but who has the wardrobe and acting chops to do the idea justice?
Earth, Sol system, Western spiral arm
Share this story
Next Page of Stories