Member postings for SillyOldDuffer

I wondered that too. Reading Wikipedia's article on Remote Keyless Systems suggests only one type of fob actively responds to the car. They seem to be fitted to high-end cars, the sort stolen to order, not the average banger I drive!

A potential problem with shielding an active device in a tin is that the receiver might flatten the battery by winding the gain up in an attempt to stay in contact with the car. Mobile phones in areas of poor reception can do this. But I think it unlikely, because most cars are parked a considerable distance from their owner whilst she's at work or shopping. So I expect the fobs receiver is always on, deaf as a post and consuming a couple of microamps, but it doesn't transmit until it hears the car loud and clear. No problem with the car polling with a low power signal because it has a massive battery.

Security is a constant battle between the clever chaps who develop systems and the clever chaps who break them. Usually it's only a matter of time before a security system gives way, so they always have to be backed up by something else, such as the police turning up. Our job is to delay the bad-guy for as long as possible, for example by locking the car in a garage with a decent door, with a Denver Clamp, and a steering wheel lock. None of these are good enough in themselves, but the combination will put most thieves off.

Make the car less attractive. Don't leave money or anything that might be valuable visible inside. Personalised number plates attract thieves because those cars are likely to contain lots of expensive bling. Not owning a high-end car at all works quite well. Ordinary modern cars are fairly well protected which makes them more bother to nick than is worth it.

Dave

Michael's link opened a box of breakfast delights for me. 'What controls toughness' leads via 'Effect of Retained Austenite', to a forum post on Cryogenic Heat treatments.

When heat treating steel, I guess we all understand the importance of of heating the metal to the correct temperature for sufficient time for the internal structure to change before catching it by cooling rapidly. Never occurred to me that cooling below room temperature might result in a further improvement.

In most workshops heat treatment ends naturally at room temperature, but there are steels that benefit from going much lower: 'For example, a fully austenitized 1020 steel with 0.5% Mn and 0.4% Si would have 1.1% retained austenite at room temperature, 0.3% at dry ice, and 0.1% at liquid nitrogen temperature.

More info on Wikipedia

Now I want a few gallons of liquid Nitrogen to play with...

Dave

Yeah, it's a problem! I see it as a consequence of past mismanagement, due to UK governments and voters choosing to ignore where bank profits were coming from. For 50 years the financial system was wide open to abuse, not only in overseas dependencies like the Cayman and British Virgin Islands, but much closer to home in the Isle of Man, Channel Islands and the City of London. Not a uniquely British problem because many other countries did similar.

Party on until it became painfully obvious that society was being undermined by a banking system that enabled large-scale corruption, tax-evasion, money laundering (drugs, people trafficking etc), sanctions busting, arms dealing, fraud, terrorism, and anything else dodgy involving money.  Got too spicy and now countermeasures being applied.

Unfortunately it's been extremely easy to open a bank account for a long time - for 50 years hardly any checks were made. As a result large numbers of existing accounts are bent, many masquerading as small businesses, charities, and clubs etc. The only way to find out who the malefactors are is to require account holders to identify themselves to a higher standard. Banks can't tell the difference between Samsaranda's Group and a small money laundering operation.

Banks have been reluctant to tackle the problem. Partly because putting legitimate customers through the mill upsets them, but a cynic might suggest banks prefer not to know where their profits come from. For whatever reason, progress has been slow and government and Regulators are leaning harder on financial institutions - sort this mess out or else. Again in cynic mode, it's possible Samsaranda's Bank has been set a target to prove 'n' accounts this year, and it suits them to pick on lots of small accounts that are unlikely to be wrong than profitable big money accounts that could be bent.

Who is guilty? We are. In the past, folk voted for tax-cuts or improved services rather than ask awkward questions about how they would be paid for. Or they knew what was going on and decided it was worth it. To my shame that group includes me.

Dave

Edited By SillyOldDuffer on 03/06/2023 11:45:54

I agree software is the likely cause. I've confirmed a few things it's not:

• Pendulum period as measured by the Arduino is steady, apart from the expected temperature and pressure changes that don't explain a constant drift. Nor is the drift explained by the average rise UK in temperature as summer approached.
• The going increments correctly, so the clock should average UTC - unlikely to be spot on, but always nearby.
• NTP on the Raspberry is OK (usually within 30ms of GPS) Like the pendulum, NTP varies around average UTC, and doesn't drift.
• Not running out of memory, or at least that's extremely unlikely

Related to running out of memory is integer or buffer overflow, which is possible. Still looking, but I've not found any candidates

Also under investigation is USB/serial comms delay. Not looking likely, as it seems to be fairly constant, and I can't think of a way it would cause constant drift.

I'm probably missing something obvious. Meanwhile, I upgraded the software last night. Not expecting much because it only removes some dead code and fixes a few buglets. Having to let code run for a day or two to confirm it's working properly doesn't help. I share your test team's pain!

Dave

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I suggest it's the installation that's industrial: 3-phase and many kilowatts. It's electrically nothing like a bungalow in Penge! In my book if it looks like a duck, walks like a duck and quacks like a duck, it is a duck. Could be wrong, but I wouldn't expect the meter on something like that to be domestic.

I think the dispute is because a domestic customer wandered into in industrial territory. Installations on this scale are rarely operated by retired private individuals. Most of us, me included, have bog-standard household electrics with domestic meters that measure real, not apparent, power. In our homes those LED lights would save us money exactly as advertised.

As industrial meters typically measure apparent power it's possible that these lights didn't save money in this installation. 'The only meter that is relevant here is the one by which you are charged by your electricity supplier'. Spot on, but I don't think it's a domestic meter: worth checking I suggest!

I'm fairly sure the issue is due to Power Factor and that the LEDs weren't really consuming lots of energy. Industrial customers are familiar with Power Factor considerations, most domestic users have never heard of it and don't need to care, lucky them. Here's what the NTOC has to say about Power Factor in what I call industrial circumstances:

Heavy responsibilities are placed on industrial customers because they often have unusual electrical requirements likely to mess up the power factor, making it necessary for them to design an installation that satisfies the rules. Money is a strong incentive - if an industrial customer fails to correct his Power Factor, the meter charges for apparent power and his electricity bill shoots up. The meter charges for real power only when the PF is within limits. The point is Power Factor would explain why the LED lamps were apparent power hogs.

Simpler rules apply to domestic consumers because we're all much the same electrically. As most home and office devices come with a 13A plug, we're predictable!

No point in arguing about it on the internet; it's the suppliers Terms and Conditions and his meter that decide.

Dave

Is it me or are the dimensions wrong in the drawing? A 12 x 12 square isn't cut by an R7.2 arc as shown.

In his first post Mick mentions using bushes made from a rod with a slot milled in it. That's what I would do, and braze them.

Maybe the handle is designed with an asymmetrical socket with one curved side because a slotted bush of the required shape is easy to make and to fit into a round hole. The designer intended it to be fabricated with a bush? I could be completely wrong - maybe asymmetry is to stop the handle of a safety critical valve being fitted at the wrong angle, in which case a weak brazed bush is dodgy.

Dave

Ho, hum, bum!

Latest result not good:

As can be seen, the uncompensated clock kept reasonable time for 2.5 days with bumps explained by the weather, then at midday it started losing time in a near straight line, i.e. constant drift.

I have no idea why. Nothing happened at midday, and the drift isn't obviously related to temperature or pressure. The pendulum seems OK. Nor is NTP to blame. Possibly my logger program or the operating system is introducing a delay. Or drift correction has mysteriously turned itself off. (Thinks - overflow?)

Another oddity is ringed in red. Just after midnight the rate of drift slows until about dawn. Could be daylight or temperature related.

Although the parts needed to build the vacuum enclosure have all arrived, I see no point in sucking air until this latest problem is fixed.

About 25% into a giant tidy-up too. Tedious and tiring, and I haven't started on the workshop mess yet!!!

Dave

A colleagues wife worked at Pucklechurch Prison when it specialised in young offenders. She taught her husband all her boys knew about twocking, Taking Without Consent, and he became the go to guy at work whenever people lost keys or locked themselves out of their cars. (Top quality design made it simple to lock cars with the keys inside.) Anyway, not difficult to get into cars made well into my middle age with a hook made from a coat hanger, and even easier with a length of strip steel with a notch in it. Also easy to hot-wire cars - the cables weren't protected. Hope they're better made now, but a fit young man could defeat most 20th century ignition locks simply by wrenching the steering wheel. Anyone could do it with a crowbar!

I don't think twocking was high-skilled work. My mate lent me his 750cc mini, the early model that opened the doors by pulling cords. Late for work, I rushed up to it and opened the door with what turned out to be my cheapo briefcase key. Didn't even look like a car key! The lock must have been very basic.

Dave

I looked into this when I started with SE too. I'm pretty sure the software doesn't identify changed files.

CTRL-S saves the current file at any time. A timer can be set to issue save reminders, default 60 minutes. As it's a nag, I turned it off. Otherwise Files are saved when the package shuts down, or are Closed. There is an exception: the Close-and-Return button keeps the file in memory without saving it.

The reminder and Close-and-Return behaviours suggest SE doesn't encourage user saves. From our perspective, saving can be a bad move because it destroys the the Undo/Redo list.

May also be to do with the way SE manages big models. So far I've not modelled anything with more than about 40 components, which is a tiddler model compared with what SE can develop. SE provides ways of managing giant models that probably break the simple IN/OUT relationship between a file on disc and its contents in memory. SE allows files to be opened, worked on, and temporarily unloaded from memory to create space for more components to worked on. A behind-the-scenes file/memory management scheme is needed to do this, and the performance/capacity benefit of memory management is reduced if nervous users keep saving to disc.

However memory and files are managed under the bonnet, SE models seem to survive power-cuts etc. In my experience it's reliable. I've not found the absence of file changes tags to be a disadvantage.

In any case, believing saving files copies them to a safe place is mostly wishful thinking! It worked in the good old days when operating systems didn't use RAM unless they really had to. Not now! After about 1995 Operating Systems utilise all the RAM available. The most common use of 'spare' RAM is improving performance by loading and editing files in RAM, and only flushing files to disc occasionally. Thus it's possible that all ctrl-s does in modern software is set a new milestone and zero the undo/redo list. It's the operating system that decides when a physical save takes place, not the end-user.

Dave

Edited By SillyOldDuffer on 01/06/2023 09:56:50

Patience and persistence.

5 tactics available:

• Tapping the drawbar sharply with a hammer applies a peak shock pressure to the joint that's likely to unlock it. When the taper is normally tight, tapping the drawbar with a hammer is unlikely to damage the bearings. Folk worry it might, but I've never seen a report of actual damage, and the method has been in use for about 160 years. I think most of the shock energy in the blow is absorbed by releasing the taper, and has little impact on the bearings. Pounding on a jambed taper is ill-advised!
• Soaking in penetrating oil. This helps if the cause is corrosion or gummed up oil sticking the taper together.
• Heat is effective against corrosion, gummed up oil, and a tightly wedged taper. It works by expanding the metal on the outside of the joint faster than the inside. Simply blasting the whole lot with a torch and keeping it hot is more stressful than quickly heating the outer to sizzling hot (a little above 100°C) and then letting the whole thing cool down for an hour, less if cooling is available, repeat several times. Each hot/cold cycle moves the joint slightly and it will eventually give. You might speed the process by giving the slightly loosened drawbar a couple of sharp taps with a hammer immediately after the torch is switched off. Heat and shock together,
• Wedging applies a steady pressure which is kind to the bearings but has little shock effect. I use two slotted wedges sliding over each other from opposite sides to release drill chucks. One wedge is supported with a lump hammer whilst the other is banged home with a small one.
• Ady's sideways cutting method has worked well for me. Set the mill up to take a heavyish interrupted cut into some awkward scrap. Undo the drawbar. Side-cutting with more than normal vibration and chatter is good at undoing taper joints.

In the absence of corrosion or gummed/caramelised oil, the most likely cause of a serious jamb is putting a cold taper into a hot socket and then over-tightening the drawbar. When the hot socket cools, the resulting shrink fit is super-tight, even after the drawbar is undone. Even worse when in place long enough for a little corrosion to take place as well. Or for the oil to gum up. (3 in 1 isn't a good choice on tapers..)

Dave

Edited By SillyOldDuffer on 30/05/2023 12:37:36

Edited By SillyOldDuffer on 30/05/2023 12:38:42

You can't generalise about PDF being safe or unsafe: it depends on what's inside, the editor that created the PDF, which reader is used, and the operating system. In particular, PDF is a container format, not a straightforward file. It can contain active code such as Javascript, Java, and embedded media (including the famously high-risk Flash)

PDF has vulnerabilities, so take warnings seriously. Much depends on what you have. A file that's low risk on a modern HTML5 based browser could be high risk on an ancient version of Acrobat,

When an alert is received, answer these two questions:

• Is the computer up-to-date?
• Do you trust the source?

In this example my computer is up-to-date AND I trust the source.

The index has been made available for years without causing problems, the author is well known, and David's been kind enough to offer reassurances on the forum. To me ME Index is low-risk.

In sharp contrast, I wouldn't open a PDF that Google or anyone else warned me about if I didn't trust the source or my computer wasn't up-to-date.

Downloading stuff despite warnings is asking for trouble. It's in the same class as believing that the dodgy phone call really is from 'Microsoft', that your computer really is sick, and that you really should install their software so they can fix it for you...

Dave

Nothing does! Up until about 1850 workshops and craftsmen made their own threads, to whatever approximate diameter, form, flank angle, and pitch they thought best. Using standard threads caught on slowl, and British clock makers were ultra-conservative.

The only way I know is to measure them. With luck they will be found to match to a standard for which taps and dies are available. Otherwise they have to be bespoke. Not difficult in principle, but fiddly. Female threads can be imprinted on a soft wooden dowel by screwing it into the hole. The professionals use shadowgraphs and other gizmos to do this accurately. However, males can be measured at home with a caliper, v-angle gauges and a loupe. A USB microscope and pixel measuring software would speed the process considerably if more than a few need to be investigated.

Once the thread's properties are known, a tap can be made in the lathe. And from the tap, a die.

I guess (but don't know!!!) that pre-standard clock threads will be similar. For practical reasons, thread applications have a limited range of useful pitches and diameters. - for example, fasteners all have thread angles between 48° and 60°. Thus, a fairly small set of home-made taps and dies might cover most clock repair requirements.

Dave

The distinction between illegal and unlawful applies. Clearly illegal when a law specifically forbids it, such as possessing an unlicensed firearm in the UK. Unlawful is much broader, covering anything contrary to and unauthorised by law, including stuff that isn't specifically forbidden.

Not illegal to repair a ladder, or to use it yourself. So far so good!

However. expect legal trouble if a home repaired ladder fails whilst being used by someone else. Worse if the ladder fails after a professional repair, or is owned by a business and an employee is injured. Order of magnitude more expensive if the failure injures a passer by.

Most businesses choose not to take the risk of repairing ladders. New ones aren't expensive, are properly made, and the owner isn't liable for the consequences of supplying kit that might fail due to a botched repair. Different story when expensive safety-critical equipment like an airliner is maintained. The work is never done untraceably as a side-job by a workshop optimist! Or shouldn't be.

Seems to me that most practical men don't know how much accidents cost. Not being personally responsible makes it easy to be gung-ho about H&S. Very different when you carry the can and know fatalities cost a couple of million each. Life changing injuries are even more expensive. That's just the money, the impact of accidents on people and their families is often off-the-scale.

Dave

Years ago a colleague married to a senior policeman had their Mercedes stolen off their front drive whilst she and Superintendent hubby watched TV about 20' away. Saw and heard nothing.

No electronics involved, the thieves arrived with a crane on a flat-bed truck, passed straps underneath, and lifted the car over the gate and on to the truck. Only took a few minutes. A neighbour had seen the car being lifted and assumed it was being taken away for repair. Never seen again. No suspects identified.

Dave

Other way round unfortunately! Not upgrading computers causes far more trouble than keeping them up to date.

Trouble is security loopholes are discovered after software is delivered, maybe years later. The only way to fix flaws is by upgrading. Or avoid the risk by disconnecting entirely.

In the Meta Pixel example there's nothing in W7 or an older browser that automatically stops it working. It, and similar, can be blocked but the user has to configure his browser. Assuming an old set-up will resist a new attack is wrong. (Not just computers, All assumptions are iffy! Check!)

Of course new technologies bring different risks. For example, as far as I know, the original Internet Explorer made money through sales. In contrast, Edge is 'free', but it earns money by collecting user data so that advertisers can target individuals. Unfortunately, collections of user data can also be used for nefarious purposes.

What I do:

• Linux is safer than Windows, so is used for almost all browsing.
• Firefox has enhanced privacy features compared with some other browsers and being Open Source isn't monetised by a commercial owner.
• Firefox is configured by me:
  • The Search Engine is DuckDuckGo, not Google, Bing, Yahoo etc. (DuckDuckGo promise not to track)
  • I have also installed 'DuckDuckGo Privacy Essentials'. On this forum page, which is low risk, it has blocked Facebook, Crazy Egg and 2 different Google trackers. Because I allow advertising on this site it permits Ads from google, gstatic, and advintage that would otherwise be blocked.
  • Generally I block adverts because the difference between legitimate Ads and trackers is narrow.
• GDPR and other legislation requires sites to ask permission before they use cookies. If the site offers a plain 'Reject All' button, use it. However, many sites ask permission in ambiguous ways: it's not clear what acceptance actually blocks and allows. 'Legitimate Interest' is meaningless. I walk away from these. Websites that have chosen to be unclear about cookies are likely to be collecting more data than I want to release.
• Internet hygiene is important. Although most legitimate sites are safe-ish, avoid off colour humour, political, porn, gambling, drugs, or anything else that fluffs your interest with dodgy material.
• I do not assume that any of the above, or the security measures I haven't listed, are valid for ever. For example, I periodically check the Firefox is still a good choice: software changes rapidly, so it's always possible a different browser, ad-blocker, privacy tool or whatever else will do a better job.

I'm Windows 10 at the moment and dithering about going to W11. Doing so involves making a BIOS change and it could go wrong! But the clock is ticking - W10 goes out of support on October 14, 2025. Functionally W11 doesn't do anything I want, so I could leave it alone. But this introduces another risk, which is the size of the gap that has to be jumped between an ancient version of an operating system and the newest. Best to keep the gap small: apart from the increased risk of a technical malfunction, anyone jumping from W7 to W11 will find a multitude of differences when they arrive. An when I fire up W11 I know Microsoft will have switched off all my security selections and I'll have to wade through putting them back. It's a pain. Unfortunately, procrastination usually causes even more hassle in the long run.

Dave

Really good fun spending Roossone's money!

From the beginning my outfit included a computer, printer and 2D-CAD (QCad) Spreadsheet, Word processor and graphics tools too.

Now I spend a good deal of time with 3D-CAD, which supports complex designs, and saves time in the workshop. Can be done on a laptop, but a fast computer with two big screens is much better. Most of my prototyping is done on a computer supported by a 3D printer, so when I cut metal there's a good chance all the bits will fit together. Pity in a way because I enjoy working my machines. Again the value of CAD tooling depends on what the workshop is for: being experimental means I do high proportion of original design. 3D-CAD is much less valuable when an engine is being built to an existing design. CAD is also less useful if the workshop mostly does repair and restoration work.

Although well equipped now, I got plenty of fun and interest out of a mini-lathe and basic hand-tools. There's no need to spend enormous money on day 1. May even be better not too.

Except you need an angle grinder and a packet of cigarette papers...

Dave

The Texas link has to be read carefully because it suggests human misreporting on Reddit as well! Have to determine by experiment if ChatGPT recognises it's own output or not: British Prime Ministers and ex-American presidents definitely don't! 

Four examples of deep dishonesty in UK public life in the news at the moment.

I don't know if the Professor was a fool or not. According to the Texas link, one student has confessed. Possibly the professor suspected foul play and tried to scare his students into admitting it. No surprise that a proportion of students cheat by whatever means available.

My view is that we live in an imperfect world. In it there's a distinct possibility that AI will be more trustworthy than people! Dishonesty apart, of course AI will make mistakes. So do people, all the time, and on a grand-scale. I don't think there's a reason to trust anybody or anything without checking the evidence.

Dave

Edited By SillyOldDuffer on 27/05/2023 11:01:51

Clock still performing well. After subtracting the synchronisation error, it's 1.128s fast at the moment. However, although drift is averaging near to zero, my clock and NTP differ by up to 2.5s, and my clock is always a bit fast. The variation in time difference mostly due to pressure and temperature changes, so turning compensation on and sacrificing a virgin should fix it. Not sure what's causing my clock to consistently run a little faster than NTP; I expect it to run 50/50 faster and slower than NTP. Could be because average temperature is rising as the UK moves from spring to summer, so the average period has changed slightly since calculated a few days ago. If so, the swiching compensation on should fix it.

Think I know what's wrong with my synchronisation code - I'm sending half the required value.

Dave

Edited By SillyOldDuffer on 27/05/2023 10:23:35

No problem. Two examples on the bottom of this photo, the right hand one is unmodified, The left hand one has been bodged by unsoldering the IR sender and photo-sensor and wiring them via choc-block terminals to the white holder. The bob breaks the beam as it swings between them. (The two electromagnets were an early experiment.)

The modules are very common, prices vary depending on source, this seller on Amazon is offering 20 for £12.99

The electronics are basic, consisting of an LM393 comparator chip, a pot, an IR LED, a phototransistor, a few resistors and a couple of indicator LEDs. Three pins: 5V, Ground, and Output.

The IR sensor and sender are ordinary, typical of the type found in TV remotes, with a wide beam - usually 35° Not ideal, but work reasonably well. They have to be protected against ambient light, and perform better when contained in tubes that narrow the beam. My tubes are slotted at the output end, and can be rotated to angle or narrow the effective aperture.

I'm finding SK and Joe's comments on Comparators and Schmitt triggers interesting. It's yet another aspect of pendulum design with hidden depths. Although I know a bit about Op Amps, Comparators and Schmitt Triggers, I'm not an expert! When reading their comments, bear in mind that John and I are both using modules rather than bespoke circuits. I don't think either of us are keen to build SMD circuits! So although the trigger points of a Schmitt Trigger circuit can be altered with a some sums and a pair of resistors, John might have trouble changing the resistors buried inside his encapsulated module. Likewise, though I could reconfigure the Arduino module as a Schmitt Trigger, it's hard for Mr Clumsy here to do.

Dave

H&S is always worth a thought, but the risks in a Model Engineering workshop are low. Maybe a fire extinguisher. Safety glasses or a visor, occasionally ear-defenders. I wear steel toe-capped trainers, and maybe gloves, Two types of glove: rubberised fabric work-gloves for shifting stuff and cleaning up, but not near spinning machines; thin disposable latex to keep paws clean when working a machine (because they tear off if caught), or using chemicals. Latex also to keep finger marks off clean work. Nitrile is better than latex. However, barrier cream is also good alternative to thin gloves, and bare hands aren't daft unless you have sensitive skin,

Experience usually resolves which type of hand protection is best in your workshop. Experience also influences many other purchases. Much depends on what the workshop does, so there's an argument against creating a big list on day one. Particularly when a beginner isn't sure yet where the hobby will take him or is general-purpose. A lot of money can be wastered on tools that are rarely needed, in the worst case blowing the budget just before realising something important and expensive is needed. I don't need one, but I've noticed live steam specialists often put their engines on a motorbike lift.

If I was putting a big well-funded workshop together from scratch it would be very brightly lit, with lamps positioned to avoid shadows, and I'd put a lot of thought into maximising productivity by positioning tools and stock 'just so'. Compared with my Chinese mill, Bridgeports come with a galaxy of conveniences that speed up workflow. It's a shame to undermine these by storing collets boxed in a distant cupboard rather than mounted in a rack with the mill. Ditto cutters, edge finders, and all the other mill related stuff - it should all be within easy reach of the operator. Same applies to the lathe. The idea goes further when a workshop has a particular workflow, say from mill to lathe, to bench and back to mill etc. Which alters were the power points go...

How well insulated is the space? Poor insulation leads to condensation, so it should be beefed up before filling the space. If damp turns out to be a problem, a dehumidifier may be needed.

I started with a big list, but prioritised it before spending any money, ruthlessly starting with essentials only. Didn't get it completely right, but so far I've only made one completely useless purchase (a cross-vice), and 3 not so smart (a 3 in 1 sheet-metal tool, a flood cooling system and a press. Nothing wrong with them, but they're rarely needed for what I do,) In contrast, owning 3 DIY worktables and a medium crowbar is very handy.

Dave

Edited By SillyOldDuffer on 27/05/2023 08:35:13