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Ask Slashdot: What's On Your Hardware Lab Bench?

mschiller Re:An O'Scope (215 comments)

But then again I work on custom FPGA-based mixed signal boards and therefore have a lot of custom interfaces to debug... For a micro-controller based project running on Linear regulators?? Yeah you could probably get by with a Logic Analyzer, but that isn't going to cut it for more complicated stuff like my project at work or even the design of a Video card or the main board of your Laptop.

about 4 months ago
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Ask Slashdot: What's On Your Hardware Lab Bench?

mschiller An O'Scope (215 comments)

If you're actually designing from scratch a new digital PCB, you can do without a lot of stuff but a 2GHz or faster O'scope is essential:

1) Debug of Switching Power Supplies [could get by with 100Mhz scope for this...]
2) Debug of high speed digital AC effects [line impendance, termination etc]
3) Verifying Setup / Hold of interface busses
4) Determining margin on variety of interfaces

Seriously. First tool a high speed scope... And Garmin International: 300MHz is for yesteryear, today most engineers need at least 1GHz to get by in digital design

2nd tool: a Good DMM
3rd tool: A thermal camera for when things go dreadfully wrong..

Other tools are gravy... [Though clearly a power supply is non-negotiable...]

about 4 months ago
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U.S. Independence Day is a ...

mschiller Re:When exactly was this, exactly? (330 comments)

Actually we are at peace right now and have been since the end of World War II (which depending on you interpretation ended on one of the following days: 9/2/1945 or at the Paris Peace Treaty 2/10/1947 when war was officially ended against the minor axis powers after the defeat of Germany and Japan earlier in 1945)

See: https://en.wikipedia.org/wiki/Declaration_of_war_by_the_United_States

The fundamental problem is that we have been having illegal wars since WWII. In WWII congress and the president did the right, constitutional thing: The president asked congress and congress gave a declaration of war. In Korea, Vietnam, the Gulf, Libya and Afghanistan (and others). The president did not insist on, nor the congress give a declaration of war. Therefore we are officially at peace. Without a declaration of war we are at peace. So we've been at peace for over 66 years.

So the original op, is somewhat correct though he fails to recognize that the 40 year span is actually the current span (+ many more years)

Personally I don't think the President should have the power to commit troops to another country for the purposes of war-like operations without a declaration of war from congress and I think the War Powers Act is unconstitutional. But congress apparently doesn't have the balls to either do the right thing and commit the US to a real war with clear objectives (by declaring war) and give the military full authority (and money) to win the war OR tell the president to shove it and not assert powers he doesn't have and stop waging war without congress first declaring it. The problem is the politicians don't want to declare war, because since these wars are controversial they can play politics to be seen to be on whatever side has the most for them to gain. They can play games with the budget, the scope, and other things by not declaring war, things that would be much harder with a declaration of war....

about 9 months ago
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USA Calling For the Extradition of Snowden

mschiller Re:Doing what is right... (955 comments)

I agree with you. Since I reject that spying on the American people can be justified without a Warrant for the specific person/information that is to be found. Eg the 4th amendment.

1) Releasing sensitive information on how we spy on Terrorists/other countries can easily be argued to comfort or aid "terrorists". Therefore the US Government will at least consider the charge of Treason.

Do I agree that this material aids terrorists? Not really. But that doesn't matter they will make the argument.

And for some of the sheeple in the US, that argument will per persuasive because we are all to ready to give up our liberties for "security".

about 10 months ago
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USA Calling For the Extradition of Snowden

mschiller Re:Doing what is right... (955 comments)

Oh there is plenty of stuff that probably justifies a top secret stamp.

Examples:
1) Landing location for a major offensive in a declared war. [Eg how much better could Germany have prepared, in WWII, if they knew exactly which beaches we were planning on using and what day we were going to launch our offensive...]
2) Technical specifications for NEW military hardware
===> Once the hardware is out there for a few years, say 7 years, the secret rating probably isn't as justified
3) Technical specifications for Nuclear bombs (no age limit...)
4) Identities of Our Spies operating in foreign countries
===> Note, I'm not stating that spying on folks is a correct thing. But if you accept that we must do it, because everyone else does it, then the spies identities must also be protected.

And probably lot's of other examples.

about 10 months ago
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USA Calling For the Extradition of Snowden

mschiller Doing what is right... (955 comments)

We have an obligation to do what is right and proper above any other law. In the sense of the USA government, the Constitution is the highest law and lies out what is right and proper. If our government is unjust and doing something unethical and against the constitution, then we must first do what is right and proper to protect the constitution.

Our Government is given power by the people, if they steal powers without consent of the governn than the highest law calls us to correct the misdeed and that trumps the laws on secrecy, etc. A soldier need not follow an illegal order!

Now that being said: Breaking confidentiality on top-secret stuff is no laughing matter. It's treason, a capital offense. But that doesn't mean we aren't called to follow the higher law if the top-secret stuff is in itself illegal.

about 10 months ago
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Let Them Eat Teslas

mschiller Not really the same (461 comments)

While it would be easy to say Government just prefers the sheeple broke and stupid... These really aren't the same. Cars can be repo'ed.. Your education can't be repo'ed.. Further from a Govt perspective the return in tax income from your education is risky.. You might never finish school. Might end up working in India and not paying taxes.. You might never repay those loans if given the choice because you won't lose anything.. The car might seem like a loss, but you will definitely pay taxes on stuff for the car like tires, registration and property taxes etc the employees who built the car will pay income tax etc. Plus there is the political side of green jobs.....

1 year,16 days
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Is Safe, Green Thorium Power Finally Ready For Prime Time?

mschiller Re:NO (258 comments)

You have a good point of course. But a lot of the cost of a nuclear reactor is in the safety systems. Which is being driven not my mathematics, but fear. Fear is the root cause of NIMBY. If we attributed the deaths caused by coal into the safety of mining and coal plants they would be alot more expensive too (but we don't, those are relatively hidden cost, while nuke absorbs some of those). We fear nuke power because of three relatively bad plant disasters in older style plants. Two of which are directly attributed to human error (TMI and Chernobyl) caused by improper operator commands.

I argue that we should go back to the drawing board. Do the research and get a safer design.

So to get cheap Nuke power we need:

1) Simpler safety systems as new designs incorporate safety by design rather than relying on pumps, electricity and human operators
2) Improved Training courses
3) The ultimate goal: Mass production.

Right now every plant is unique. We spend billions doing safety assesments, environmental impact studies, training, and inspecitions etc. What if we got to a design that was an appliance? Where you could get one installed next to your house, or one in every city or something?

Pebble bed reactors potentially would allow this...

Because it's not the fuel that makes nukes expensive it's the safety related stuff. And a better, newer, design might very well simplify the safety issue.

about a year ago
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Is Safe, Green Thorium Power Finally Ready For Prime Time?

mschiller Re:NO (258 comments)

I agree, but that doesn't change the fact that there is an awful lot of NIMBY going on. We could've and should've been building new reactors since the 70's, but instead the reactors that are online are mostly still the original first generation designs from the late 50's and early 60's. The same whack job environmentalists who should be all for this, are also typically the most adament against it. Yet watch them and their energy use isn't substantially different then any other American....

I suspect by the time we figure out that we can't put up with this NIMBY crap we will be OUT of oil OR have completely screwed up the environment once and for all...

I mean really this was the first new nuke plant licensed in 30 years:
http://money.cnn.com/2012/02/09/news/economy/nuclear_reactors/index.htm

And it's the AP1000. Still a Water based design and Generation 3.. Though from the look of it a lot safer than most of the reactors (Gen 2) in operation

about a year ago
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Is Safe, Green Thorium Power Finally Ready For Prime Time?

mschiller NO (258 comments)

Why?
NIMBY

about a year ago
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Current Radio Rules Mean Sinclair ZX Spectrum Wouldn't Fly Today

mschiller Re:Abject Failure? (64 comments)

4Layer? It was probably 2. But a worse case scenario would've been to make it more. Remember we're talking today.. Today an 8-layer board is nearly as cheap as a 2-layer board and if it meant having a legal product it would've been done.

about a year ago
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Current Radio Rules Mean Sinclair ZX Spectrum Wouldn't Fly Today

mschiller Abject Failure? (64 comments)

"It’s not just a failure; it’s an abject one" Really? Now I admit the situation could be a ALOT worse with the accessories and cables, and until you've ran the test you don't know. But it's only about 6dB above the line, I've seen a lot worse problems [try 20dB!]. There is a good chance this would be a relatively easy fix when you start looking at the problem.

A ferrite bead on the power supply cable would probably fix the "bad power" supply if indeed that's what it is. And some judicious copper taping would likely fix the other problems. Worse case you do a board spin and add ferrite beads to the I/O and possibly move suspect traces into internal layers. Worse WORSE case you change the clocking to use spread spectrum which would likely not require any changes except in the clocking circuits. None of those would prevent a "modern" version of the product from going to market.. And a good engineer could probably implement them in less than 6 weeks in a production environment...

Plus it doesn't even manner, if you were going to bring a sinclair back to market it would draw about 20mA, run on USB power and be completely implemented on a single chip.... Because it has roughly the same processing power as a PIC uC.

about a year ago
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Dell's Ubuntu Ultrabook Now On Sale; Costs $50 More Than Windows Version

mschiller Re:Boatware (403 comments)

Practically? This clearly demonstrates that it pays for the windows license and is also a revenue stream. Either that or Dell is sticking it to linux users just to get a few more bucks... Probably a windows machine that they just pay some high school student to install linux onto....

Who wants to take a bet there is a windows 7 key on the bottom of the laptop?

about a year ago
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Chuck Schumer Tells Apple and Google To "Curb Your Spy Planes"

mschiller Re:Security by obscurity? (302 comments)

Apparently, pushing refresh and then posting a reply comment is not sufficient. The backend for Slashdot must not be fully synchronous. We must have posted at the same time and non had made the comments page yet, even though they were working their way through the database.

about 2 years ago
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Ask Slashdot: What To Do Before College?

mschiller Enjoy your summer... (335 comments)

If you don't need the money, enjoy your summer! Spend time doing hobbies, volunteer opportunities, working on open source projects [programming]. Worry about education and internships when you get to college.

It'll be A LOT easier to get employed after your sophomore year. You should try after Freshmen year, but no guarantee it'll happen.

Maybe take a general ed class that will transfer at your local community college if you must do "something productive"

about 2 years ago
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Chuck Schumer Tells Apple and Google To "Curb Your Spy Planes"

mschiller Re:Security by obscurity? (302 comments)

Woot!. First post!

about a year ago
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Chuck Schumer Tells Apple and Google To "Curb Your Spy Planes"

mschiller Security by obscurity? (302 comments)

Come on there must be better way... Perhaps by having a raid array of the appropriate infrastructure?

about a year ago
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Ask Slashdot: How To Enter Private Space Industry As an Engineer?

mschiller Re:State school = less debt. (283 comments)

Not necessarily. IF you get into MIT and your parents aren't super rich [of course if they are super rich you probably don't have to worry about debt either because you've got $$$ from mom and dad], they will may make the financial offer competitive or even better than State school. MIT is need blind (on admission) and academic blind on financial aid. and they have a very big endowment / devoted alumni. They are committed to making MIT affordable to everyone.

Take my example:
HS Class of 1998 (yeah I'm getting old....)
California Resident.
Son of Vietnam Vet (at the time This meant FREE tuition at California State Schools.)
Parents made ~$60,000 /year with 2 kids in college and 1 still living at home. [Solidly middle class, but not even approaching rich back then]
NO college savings [Damn parents...]

Cost of attendance (approximate numbers, after free money given by universities):

UC Berkeley: $16,000 /year [NO Free money, some subsidized federal loans, some UNsubsidized federal loans]
MIT: $15,250 /year [>$20,000 free money [MIT alumni scholarship] + Federal Subsidized loans

Loans and Summer Internships covered that with no problem.

Graduated FROM MIT with about $10,000 /debt. Not too bad. If I hadn't flown home to california 3+ times a year probably could have pushed that to under $5000, or not bought those two laptops at ~$2000 each....

more than 2 years ago
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Seeing Through Walls

mschiller Re:What they don't tell you (163 comments)

It's called coherent integration gain. It's done entirely digitally in a modern radar such as this and can in theory allow you to detect pretty much any signal no matter how weak [there are practical limits of course...] The whole radar they've described probably has a BOM cost of less than $200,000. The real gotcha is labor to make it work, not the material cost. That'll cost millions [probably >$10Million, you could find out if you want to dig through some defense contracts and find the value of this one...] but so did your new iPhone 4S. The difference is that your iPhone 4S is going to have millions made this not so much. If the government wanted to build 100,000 of these, the cost would probably drop to around $50,000....

Here's the idea:
1) You transmit N identical pulses of radar waveform (probably an LFM or NLFM waveform for this application)
2) They bounce off the target and return to the radar
3) You receive them. They are WAY below the noise figure (say 50db). No amount of normal filtering will get them back. You have to analyze the noise for something that isn't "noise" like....
4) You use a matched filter that has a maximum output when the input signal is exactly the LFM you originally sampled to "pulse" compress the signal
5) If you're lucky the matched filter output has gotten you 20-30 db of gain because it's looking on a single pulse basis for the exact signal of interest. That 20-30db gain DOESN'T apply to the noise, because the noise won't match the matched filter [random vs determinisitic], therefore you've gained 20-30db of SNR.
6) Now remember you transmitted N pulses. Why not look for a signal across all of those? That's the next step. For this application they'd probably use Doppler processing. Turns out that if you do this properly you get gain on the desired signal equal to the number of pulses, so if you transmit thousands you can get that remaining 20-30db needed to make the signal >15db SNR which is the usual minimum for reliable detection in thermal noise.

It's really straight forward. The challenges here are not in that part of the design. That part is easy..

The challenges are:
1) Making it realtime (Coherent processing doesn't work when targets lose coherency that happens when they move "too quickly"). This limits the number of pulses you can use to make useable system
2) Dealing with the Dynamic range between the (very) STRONG wall return and the very weak internal targets. [Very expensive ADCs and RF amplifiers can help, they've also apparently added a doppler filtering step in analog which is interesting.... But fundamentally it's a pain]
3) Target classification. The military could care less how many TV and appliances you have. Unfortunately those will show up as targets behind the wall too...
4) Making it small enough and draw a reasonable enough amount of power to be vehicle mounted
===> If you fix #1 with more output power or a larger antenna you run into this problem.....
4) Having enough resolution to actually differentiate 2 separate targets. Without going into the details this becomes problematic for short range radars like this....because you want to see things that are on order 1ft x 1ft.. Radar is much better at seeing Planes and Tanks...

more than 2 years ago
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Apple Laptops Vulnerable To Battery Firmware Hack

mschiller Re:This why you NEED battry packs that can b REMOV (272 comments)

Actually this may not be a vulnerability in units without a removeable battery. When a Lithium Ion [or polymer] battery is removable manufactures install microcontrollers with firmware to orchestrate the safety system and do battery life management. This firmware is often provided by the pack subcontractor rather then written by the larger system manufacturer...

The pack has firmware for two reasons:

1) There is a variety of failure mechanisms that can cause fire and explosion with Lithium Ion batteries. When the uC detects one of these is occurring the battery is either temporarily or permanently placed in "Safe" mode. This disconnects the battery from it's terminals. Since on units with removable batteries these conditions can occur outside of the unit, these important safety functions must be built into the battery. Your typical Cell phone battery has three or more terminals for these functions [even though only 2 terminals is needed to charge/discharge the battery]
===> Another safety concern is "fake" batteries which often don't have these safety features, so often the uC authenticates itself to the Laptop before it can be used. This protects from counterfeits and also makes the laptop manufacturer money on replacement batteries.....

2) Charge Cycles and battery capacity information is also stored and calculated. This information is provided to the higher level system, when the battery is inserted. This is important so your Laptop can guess (relatively accurately) how much time is left even after you change the battery to a possibly degraded or partially charged spare. [Current monitors detect how much power goes into the battery and how much is removed. Based on historical information from previous charge/discharge cycles a good guess on the remaining capacity can be made]

Things are different however in units with a non-user serviceable battery. A lot of the safety concerns can be explained away and not protected against, since the battery is in a more protected position (this all comes down to lawsuits, if you can say the user tampered with the unit and prove it then the company is off the hook...). So often they will have a "dumb" charger connected to the battery with most of the safety functions removed. A special purpose capacity monitor chip (without firmware) can be used for the power monitoring feature. Thus in a lot of systems you don't need the uC (and thus the firmware) at all, if you assume the battery can't be tampered with...

more than 2 years ago

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