* Posts by Tom66

34 publicly visible posts • joined 23 Jun 2022

Make your neighbor think their house is haunted by blinking their Ikea smart bulbs

Tom66

Re: Why???

Zigbee is only 'transiently' IoT - you can build a perfectly functional Zigbee smart home without a single internet connection.

It's the Tuya Wi-Fi bulbs that ought to be avoided (though I wish I'd known, and communicated this, before friends and family bought many of them for our home.) Said bulbs need a continuous, outbound connection to a server somewhere to work. And that company makes no promises about how long that service will be available, and the bulbs don't work all that well without the connection to the internet (they turn on and off with the power switch, but if you cycle them more than a few times they go into a bloody annoying programming mode where they flash for about 5 minutes.)

Tom66

Re: Epilepsy?

There's no risk from cycling the bulbs on and off quickly. They're already PWM-dimmed to provide the dim/colour effects, which will be at hundreds of Hz to avoid annoying users too much.

The design of smart bulbs is usually quite simple. An integrated PSU produces something like a 6V ~ 100V supply for the LED array, and maybe a secondary rail for the microcontroller. A small array of FETs switches the colour channels on and off as required.

There's usually a power envelope, so for bulbs with cool/warm white and RGB not all channels can be on at once; such an overload would probably just result in the LEDs dying rather than any fire. PCB materials are made of non-combustible UL-approved 94V-0 fibreglass. Overload protection will also be enforced by the power supply design which will fold back on overcurrent - the effect will be to blink the bulb on and off until the microcontroller resets.

Those screws on the Apple Watch Ultra are a red herring

Tom66

And what would Apple do with whatever they take back? It all just ends up as e-waste

The solution isn't to get better at recycling, it's to reduce the amount that needs to be recycled in the first place. There's no good reason a smartwatch can't last as long as a regular watch, with normal servicing.

I don't mind having to replace a battery in my "gadgets", but I do mind when that process is made very difficult and expensive, or limited to service personnel.

Soaring costs, inflation nurturing generation of 'quiet quitters' among under-30s

Tom66

Re: Wrong!!

Thank you. I measured my actual inflation level of 6% last year measured up to last month. I expect around 10% this year. It is not great by any means, but it is hardly 80% of my pay disappearing.

The biggest risk is a recession might make it harder to negotiate any raise to cover this. I'm very glad I managed to get a substantial raise earlier this year - I doubt it would be possible right now to negotiate the same despite a shortage of skilled engineers in my field.

BT's emergency call handlers will join pay strikes

Tom66

Depends upon whether you own property already or not.

I know people with £400pm mortgages creaming it in London - but they bought 20-30 years ago and are looking to a huge pension payout when they downsize into retirement. A friend of a friend in South Norwood bought their house in the mid 90's recession for about £80k and it's now worth ca. £800k.

And of course others spending £1500pm on rent - especially young people.

Not sure you can say there is a universal cost of living anywhere - and giving more to people (WITHOUT solving fundamental issues) is just inflationary as rent and house prices tend to track incomes. Perhaps a better avenue is to try and figure out why someone can't live on £50k pa in London when that's an excellent wage in most of the country.

That probably means more social housing, but that's an anathema to the current government (and a lot of the electorate, too, I suspect, who own homes.)

Tom66

Re: emergency calls?

BT are the service that ask you "police, fire, ambulance", the bulk of the call is then handled by a local operator provided by e.g. West Yorks police.

The operators are trained to direct a call to the most appropriate service - and that includes the less often specified ones (coastguard, mountain rescue, any others I missed?)

BT also provide the location services so that they know which local service to direct a call to, and the operator can try to determine that if these services aren't working for some reason.

All in all it's pretty essential work.

How Google uses mirrors to dynamically reconfigure its networks

Tom66

How Google uses mirrors dynamically reconfigure its networks dynamically,

As opposed to dynamically reconfiguring its networks statically?

Microsoft Azure cloud region settles over desert in Doha, Qatar

Tom66

Re: Just what the planet needs

Mmm, hot dessert.

But serious, yep, this is going to require a ridiculous amount of air conditioning, and you can't exactly use water to cool your radiators either, it's going to be air to air, with air temperatures approaching 50C in summer.

I really hope they put a proper solar array on top and adjacent to it, it would provide shade plus power during the daytime.

BT union announces 48-hour strike action in protest over pay

Tom66

Re: Colleagues?

Probably because the fatcat will leave if he doesn't get a raise like that.

Individual workers can leave too, but are in less demand, so can't negotiate ridiculous wages.

Tom66

Re: Colleagues?

Take his £3.2m package and divide it between 26k workers - they each get £120

Far better to focus on the £1.3bn profits, that would (if shared equally) give every employee a £50k dividend. Even 10% of that would take the sting off inflation for many.

Microsoft asks staff to think twice before submitting expenses

Tom66

Re: Microsoft managers personally paid the bill to feed and water staff at a company picnic

They're still not free. They don't pay tax on them, but they do reduce revenue. Same as companies donating to charity. Yes, it's a tax write-off, but the tax written off is always less (barring some bizarre exceptions perhaps) than the donation.

Of course, the cost of pissing off staff can be significant, and if I had been asked to cover staff expenses even as a MSFT manager on $200k+ I would be brushing up my CV pronto.

DoE digs up molten salt nuclear reactor tech, taps Los Alamos to lead the way back

Tom66

Re: REstart?

Many types of nuclear reactor design require overhaul if allowed to cool down too much because it can stress the walls of the reactor chamber. There's nothing new here.

Tesla Full Self-Driving 'fails' to notice child-sized objects in testing

Tom66

The problem is Tesla chose the word "autopilot" (and "full self driving") rather than "supervised self driving" or something like that, but then Elon is a four-letter-word when it comes to marketing.

You have to always be paying attention -- because it's still level 2 supervised driving. So what's the point? Well, it is a pretty good way to get training data in the real world without spending much $ so obviously attractive to Tesla there. And it gives the user a 'taste' of what an FSD car might be capable of. Still not worth the $10k or whatever they're currently asking for it, but fools and money I guess.

I drive a car with adaptive cruise control, from VW; in the manual there's about 20 warnings along the lines of what the system won't do. It won't stop for totally stationary vehicles. It doesn't see pedestrians. It doesn't adapt to the weather conditions. It might brake sharply if you get cut off. It might accelerate unexpectedly if you leave the road (e.g. motorway exit). It might accelerate unexpectedly if it loses the radar signature from the car in front, and you're on a sharp bend. Despite these limitations, I would not buy a car without this function. Provided you're aware of the system's limitations, and are *always* supervising it, it's a good way to reduce driver fatigue (your brain is no longer running the complex "regulate-speed-and-distance" algorithm, instead you're just "stay in lane, watch out for weird ACC stuff") which brings more safety benefits than the disbenefits of the system.

I think the Tesla AP/FSD beta should be treated this way; it's a fancy lane-assist and speed-assist system, which means you can turn your brain from "driving mode" into "monitor mode", but you cannot be using your phone or idly ignoring the road conditions. Dan O'Dowd might as well say, "look at this modern car with ACC, it ignores children in the road" ... failing to note that it's a supervised system that isn't designed to respond to that specific circumstance.

It might be interesting to note that O'Dowd also has some interesting competing interests that he doesn't disclose in the video, or in general. He owns a company selling safety-critical software and has been critical over Tesla's use of Linux (instead promoting his own operating system, 'Integrity') despite no obvious issues arising from Tesla's choice of OS.

N.B. It seems many in the press confuse 'AP', 'Nav on AP' and 'FSD Beta'. 'AP' is the original system based on Mobileye chipset, it's pretty much the same as 'lane hold' in a modern car. 'Nav on AP' is based on the Tesla AP computer and is rated for highway use only. 'FSD Beta' (also known as 'City Streets') is a closed beta for individuals with a certain attentiveness score, based on a few factors disclosed like time to take over after AP requests. Most 'FSD' issues are actually 'Nav on AP' or 'AP' issues. I'm reasonably sure the video is showing regular Nav on AP; the system is simply not *trained* to process the idea of a small child appearing on a highway.

Hi, I'll be your ransomware negotiator today – but don't tell the crooks that

Tom66

Re: stupid question

Fortunately (though not for ransomware cases), encryption algorithms are not usually vulnerable to what you describe as a "known plaintext" attack.

As an example for why this would be really bad for any serious use, think about encrypting a filesystem. If it's a Windows system, you can probably take a guess that it's NTFS, and try to break the algorithm based on likely locations for header structures and the like, or common document formats (docx, jpg, zip) or known executable images (ntoskrnl.exe, kernel32.dll might be good things to go hunting for.)

It's only particularly broken algorithms where known plaintext attacks work, and even then it usually only gives you a few bits more information that you don't have to crack (known plaintext was one of the attacks used against Enigma.)

Pull jet fuel from thin air? We can do that, say scientists

Tom66

Re: What's the catch

Ivanpah and Crescent Dunes are both still active (the latter has had a spotty past, but more business related than project related it appears.)

Tom66

Re: you focus on EVs were you can

Certainly won't be the case that anything new from JLR will last 31 years!

Tom66

It is still impossible to build a combustion engine of any reasonable efficiency (even if CO2 restrictions were weakened so e.g. 30 mpg cars became more common) that does not produce NOx.

NOx is highly toxic to humans and has been shown to lead to: breathing problems, headaches, chronically reduced lung function, eye irritation, loss of appetite and tooth corrosion. It also acidifies rain (along with sulfur dioxide) and has similar downstream effects for animals.

Besides, even if regulatory requirements for efficiency were relaxed, consumers would demand fuel efficiency remain high.

Chip startup alleges Cadence sabotaged processor rollout

Tom66

Having used Cadence IP on the Xilinx Zynq - this, so many times over. Very buggy, and many bugs are not easy to overcome. For a few bugs, there is no resolution, critically disabling certain features. Seems like there is a lack of attention to detail in verification there.

Homes in London under threat as datacenters pull in all the power

Tom66

Re: And they said...

Centralised infrastructure will almost certainly use less power than decentralised infrastructure. Especially if you can keep the utilisation of that kit at 90%+ by selling it to multiple customers.

BT accused of 'misinformation' campaign ahead of strikes

Tom66

Re: Viva!

As you type this message on a device invented, designed and innovated upon at the behest of capitalism.

Tom66

Re: That claim that it's 8% for their lowest paid workers...

Why would they be paid what they are if they didn't generate significantly more in revenue/profits? These execs typically serve at the pleasure of shareholders, so if they're making f-all difference for their ridiculous salary they'll get the boot soon enough. I don't like the high salaries/bonuses from an ethical standpoint but it's a consequence of a limited pool of suitable candidates & high demand for their services.

Shanghai surprise? Another analyst sees historic PC decline

Tom66

Infinite growth on a finite planet isn't sustainable. It's fine if shipments are down now and then.

This credit card-sized PC board can use an Intel Core i7

Tom66

Credit card sized but requiring a heatsink and fan about the same size as the module.

Engineers on the brink of extinction threaten entire tech ecosystems

Tom66

Lots of PCBs are still made in the UK. Still king for quick turn, I can get boards done in 1-2 days up to 6-8 layers at the place down the road from me. Plus very complex ones like flexi-rigid assemblies are still done here quite commonly.

Like many other things the cheap commodity high volume stuff has gone to China but that doesn't mean there isn't still a bustling PCB industry here.

Tom66

It's still a 37 hour per week job, so does it matter if it's three different specialisms? I'd get *bored* focused on just one thing all the time.

Tom66

Not a bad idea.

The problem is university degrees are too focused on the theory and not the practical day to day work of an elec engineer (and this is true for a lot of fields that have a strong practical / vocational aspect).

I would personally love to see the degree chopped down to two years and have the other two years be in industry. Pass the first two years to get the industry position. You need a great deal of theory to do EE competently, but you don't need to understand semiconductor physics or communications theory in great depth unless you're going to specialise in those fields (in which case, a 4 year course is probably best for these students, but it isn't "electronics engineering" it's "electronics and communication", for instance.)

In order to complete the degree you'd need to do those 2 years in an accredited org and in return you'd get a living wage salary during your time there. Not big bucks but covers rent so you don't need to accumulate more debt as a student.

Of course this won't ever happen because the universities love having students there for 4 years. Even when I did a year in industry it was sandwiched in the course, rather than replacing a year.

Tom66

That EE salary probably doesn't consider the sub fields of EE.

I have more than twice that salary 4 years post graduation and I'm pretty sure I could be touching on £100k going by job ads and discussing with some friends in the same field. My job title is officially "senior" electronics engineer but really I have a lot of focus in FPGA and some in software and project management. Schematic/PCB work is still done by me, but probably only a day or two in any given month.

So the curve is extremely wide, a junior might get £30k but a principal FPGA + proj mgmt + software monkey that understands h/w could be going on for £100k in even a small firm because we're really valuable and there's no many out there that can do all competently, without tooting my own horn too much.

Tom66

I completed an Electronics and Electrical Engineering degree at a major red brick university and this was similar to my experience.

When are we going to go from boring white boards to actually solving problems?

It wasn't until fourth year that we picked up soldering irons for real. I'd had many years prior as this was a hobby as well as a field of study for me, but for most students, this was their first time.

And after that year they were expected to go out into the big wide world and get a Real Job(TM)... most of them having little to no practical experience. No knowledge of PCB stackup and manufacture (we'd done machined in-house PCBs only, which -no one- does in industry). Limited experience to the process of board bringup and test. Virtually no debugging of circuits when things don't work, or understanding common failure modes.

But we did know about the precise physics of laser diodes, so there's that, I suppose. Really useful stuff.

Tom66

Electronics was still taught in schools when I was there about 10 years ago. It's one reason I ended up doing it as a degree and a career.

Smart thermostat swarms are straining the US grid

Tom66

Re: Click

"if possible"

Tom66

Re: Click

At 9pm the load for air con will be less, because the outside temperature will be lower. So this is still a good idea. Also encourages EV charging, cooking, and any other high power stuff outside of peak times if possible.

Tom66

Re: Randomized time offset ?

EV chargers use a PWM signal to set the charge current from the car. The duty cycle of this will vary somewhat randomly in a small region, that's more than sufficient entropy. Or you could use the 50Hz carrier counts from last power off, or the variation in charging current, or plug temperature or all sorts of other things to get entropy.

All you need is say 5 bits of true entropy to give a delay of 0-15.5 minutes and you've probably got enough of a distribution to make it work.

Tom66

Re: Pope is catholic, bears defecate in woods..

Or have batteries and diesel generators standing by to 'kick-start' the grid when things go wrong.

Totaled Tesla goes up in flames three weeks after crash

Tom66

Re: So when one of these things is junked ...

The battery pack has a pyrofuse in it which breaks the connection as soon as the airbags go off. The battery is effectively open circuit.

This won't really help stop a thermal event if the battery is damaged, but prevents electrocution for first responders cutting you out of the mangled wreckage.

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