Interesting findings on the internet

[tggzzz]

I suppose IoT stuff has its uses. Turning on the central heating remotely, so it's ready when you come home occurs.

Curiously I regard that as a prime example of why I am an IoT sceptic. Why heat an empty house? Just leave a sweater or coat on until it has warmed up

The one IoT thing I do have is a Ring doorbell; it was a Christmas present. That helps with my inability to hear doorbells, by sounding the vibrating siren in my shirt pocket. It also provides warning that a delivery is about to take place, or proof that it wasn't attempted.

[tggzzz]

I really can't see why anyone would wish to control a washing machine, dishwasher etc from a mobile phone, or pay extra for the feature.

Those with grid tied solar installations use remote and/or delayed appliance activation when they are at work and getting good solar output rather than have to pay the grid operator more for the power they generate for free from solar and get shit all for pumping it into the grid.

That does sound like a benefit.

[Zenith]

IoT seems to be one of those things, which seems as if it ought to be useful and has a considerable Gee Whizz factor. Some people do find aspects useful, but it's not a Godsend to millions. Things like baby cams are definitely suspect. As I recall the Bosch washing machines with internet control were considerably more than those without it, although I doubt that was the only distinguishing feature.

[tggzzz]

Too many IoT add-ons are mere shiny marketing features. I don't object provided the IoT can be switched off without losing functionality.

If you do that with modern cars, you risk invalidating your insurance, FFS. Yes, the software controlling all of the car's wheels must be "up to date".

[Zenith]

It reminds me of a lot of the projects that were published in the electronics comics years ago. A contraption to raise an alarm when your outside LPG bottle was getting low. A device to raise an alarm if the deep freeze had failed and was thawing out. Definitely of use to someone and interesting to skim through, but giving the impression of ingenuity desperate to find an expression.

"Making" and SBCs such as Raspberry Pi cater to the same sheddy, tinkering instinct the amateur electronics rags covered. It's a constructive interest and no bad thing. There's an IoT version of Windows 10 for Raspberry Pi, so Microsoft must have thought there was enough of a market and potential profits to be worth addressing. I suppose the modern freezer alarm would detect the freezer had failed and send a text message to your mobile phone. The maker could build it in at very little extra cost and claim it as a feature. I know someone who came home to a freezer full of rotting food, because while she was on holiday, poorly thought out and codged wiring in an outbuilding, had thrown the main trip in the house, which really shouldn't have happened. Possibly receiving a message would have enabled her to do something about it, but I doubt she would have come back from Italy or wherever, to deal with it.

Don't start me on the useless and potentially expensive extras with modern cars. The gas in the air conditioning in mine is exhausted. I asked about it at the MOT a week back, because I have heard that on some cars if the A/C doesn't work, there are problems with the cooling system as they are integrated. I was told that with this car that wasn't so, and if I didn't use the A/C it could safely be ignored. Depending on the gas, it would cost either £60 or £120 to recharge. In the UK I've found it pleasant two or three times a year, but nothing I can't live without. In Arizona it would be different.

[tggzzz]

It reminds me of a lot of the projects that were published in the electronics comics years ago. A contraption to raise an alarm when your outside LPG bottle was getting low. A device to raise an alarm if the deep freeze had failed and was thawing out. Definitely of use to someone and interesting to skim through, but giving the impression of ingenuity desperate to find an expression.

The sensing and display techniques were interesting, but little else.

"Making" and SBCs such as Raspberry Pi cater to the same sheddy, tinkering instinct the amateur electronics rags covered. It's a constructive interest and no bad thing.
....
I know someone who came home to a freezer full of rotting food, because while she was on holiday, poorly thought out and codged wiring in an outbuilding, had thrown the main trip in the house, which really shouldn't have happened. Possibly receiving a message would have enabled her to do something about it, but I doubt she would have come back from Italy or wherever, to deal with it.

I could have done with a freezer alarm a few months ago, but IoT devices usually require power and a working internet connection. Spot the catch 22.

Don't start me on the useless and potentially expensive extras with modern cars. The gas in the air conditioning in mine is exhausted. I asked about it at the MOT a week back, because I have heard that on some cars if the A/C doesn't work, there are problems with the cooling system as they are integrated....

My second car's air con consisted of a 24" * 3" hole behind the steering wheel.

I've long appreciated this 1980s advert. Note it does have central locking ...

[Zenith]

"Making" and SBCs such as Raspberry Pi cater to the same sheddy, tinkering instinct the amateur electronics rags covered. It's a constructive interest and no bad thing.
....
I know someone who came home to a freezer full of rotting food, because while she was on holiday, poorly thought out and codged wiring in an outbuilding, had thrown the main trip in the house, which really shouldn't have happened. Possibly receiving a message would have enabled her to do something about it, but I doubt she would have come back from Italy or wherever, to deal with it.

I could have done with a freezer alarm a few months ago, but IoT devices usually require power and a working internet connection. Spot the catch 22.

It depends on the fault you are guarding against and whether you have a UPS capable of keeping the internet connection going for a few minutes, and whether the monitor in the fridge had a battery or super capacitor to keep it going for a short time. If the fridge broke because the thermostat or motor had failed, the monitor would still have power.

You also have to estimate how likely it is to happen, and balance the cost of a failure against the cost of providing against it.

In her case the ELCB in the outbuilding was present but not wired in, neither was there an ELCB in the house for the outbuilding, most of which was an ancient barn with an apartment on the end. The wiring in the outbuilding was amateurish, and in some places hair-raisingly dangerous. There was a short, I'd guess caused by water, and the main trip in the house was thrown, disconnecting everything. Had she been made aware of this and left a key with friend, they could have been contacted and asked to reset the trip, but it's by no means certain that would have helped. The main trip could well have been thrown again immediately. The fault may have been caused by rain being blown in and getting to the wrong place.The outbuilding could have been disconnected, but you'd need to have some electrical knowledge and investigate sufficiently to isolate the problem.

[tggzzz]

Too many IoT add-ons are mere shiny marketing features. I don't object provided the IoT can be switched off without losing functionality.

If you do that with modern cars, you risk invalidating your insurance, FFS. Yes, the software controlling all of the car's wheels must be "up to date".

Today's IoT car news...

Nissan is turning off its car app with a months notice. That means cars 4-8 years old will be neutered.
https://www.theguardian.com/environment ... ect-ev-app

[MED6753]

I will never buy an EV, hybrid, or any vehicle that relies upon connectivity to operate. I hope I'm dead before that choice is gone.

2004 Civic
2010 Accord
2013 CR-V

All gas. No ridiculous "start/stop". No required connectivity. No unreliable CVT. And best of all.....no car payment.

[tautech]

"Making" and SBCs such as Raspberry Pi cater to the same sheddy, tinkering instinct the amateur electronics rags covered. It's a constructive interest and no bad thing.
....
I know someone who came home to a freezer full of rotting food, because while she was on holiday, poorly thought out and codged wiring in an outbuilding, had thrown the main trip in the house, which really shouldn't have happened. Possibly receiving a message would have enabled her to do something about it, but I doubt she would have come back from Italy or wherever, to deal with it.

I could have done with a freezer alarm a few months ago, but IoT devices usually require power and a working internet connection. Spot the catch 22.

It depends on the fault you are guarding against and whether you have a UPS capable of keeping the internet connection going for a few minutes, and whether the monitor in the fridge had a battery or super capacitor to keep it going for a short time. If the fridge broke because the thermostat or motor had failed, the monitor would still have power.

You also have to estimate how likely it is to happen, and balance the cost of a failure against the cost of providing against it.

Yup a UPS for the 'Net is invaluable when running a home business in a rural location where some are so dumb to see the risk their trees are to the power grid.
Our Mom and Pop ISP threw a small but commercial grade UPS on their installation here where we also act as a high point relay station for a few of their customers.
It gives us several hours of WiFi connectivity when the lights go out and one might have thought longer but the 4 POE antennae suck the power down just keeping them alive.
I sure don't miss having to tether the iPhone to any devices when the power goes down.

[tggzzz]

It is not clear how long connectivity would continue in the event of a widespread power failure.

1 hour I'm sure would be OK for cellphones. 6 hours is possible but I certainly wouldn't bet on it. A day is unlikely, except perhaps for emergency calls and government / police / military.

Landlines are probably similar.

[tautech]

Yup ~6hrs is all one can expect from the major connectivity suppliers.

But those that give a stuff will go to a bit of trouble to keep their systems alive.....that's if you can get a genset from a hire company before everyone else cleans them out.

[Zenith]

It will depend on the kind of disaster you are planning for. I find power cuts usually last about an hour and affect a few streets. They happen maybe twice a year. The last one was caused by a problem at the local sub station, lasted about two hours and took out most of the village. I've no idea whether they affect the cable network, because when there is one the cable modem is down. I assume the local server has power from two substations and maybe a backup generator, and so could continue for at least a few hours. There may be repeaters between here and the server which could be affected.

Looking on Amazon there are UPSs for £100 or so. Giving it a cursory look over, I'd guess they could keep a normal PC going for about five minutes, enough time for an orderly shutdown or to complete a BIOS update. They could probably keep a cable modem and a low consumption computer, such as an SBC, going for much longer.

I've just looked up automated light houses. Many of them are in remote locations. There's not much by way of details and what there is says they use solar cells and batteries. Their power consumption must be well thought out and not that high, but relying on solar power around the coasts of the UK in winter must be dicey, with short days and no strong sunlight. I assume there's a small diesel generator or two, to fire up to charge the batteries in emergencies, or maybe they have fuel cells.

Conventional landlines are a vanishing thing these days. I'm pretty sure that in the old days, the phone system was run from batteries charged from the mains, so in the event of a power outage they could continue for a long time.

[tautech]

Power outages in rural areas are a lot more common and often only last a few minutes but sometimes an hour or 3.
Big storm winds are our main risk from tree damage to the network....it's a pet hate of mine and anywhere along our road frontage I've ensured no tree can impact the infrastructure....I own several chainsaws and not afraid to use them.

A couple yrs back we had a 2 1/2 day outage, and you guessed it, from mostly widespread tree damage to lines so our little 2.5kW genset got a good workout for a few days keeping fridges, freezers, house water pump, charging iPads and phones and the PC up and running.

You just gotta have enuf splitter boxes and extension leads to manage such a nightmare.
Cooking and boiling the kettle is easy with the camping gear but house hot water requires kicking the log burner with a wetback out from summer retirement.
Still, after a few days you get well over this no power BS.

I remember Pop telling me power came through here in 1935 when he was preschool age and they marvelled at no longer needing kerosene lanterns and candles at night.

[tggzzz]

It will depend on the kind of disaster you are planning for. I find power cuts usually last about an hour and affect a few streets. They happen maybe twice a year. The last one was caused by a problem at the local sub station, lasted about two hours and took out most of the village. I've no idea whether they affect the cable network, because when there is one the cable modem is down. I assume the local server has power from two substations and maybe a backup generator, and so could continue for at least a few hours. There may be repeaters between here and the server which could be affected.

One recent experience...

"In December 2015, life for more than 100,000 people in Lancaster reverted to a pre-electronics era. A flood at an electricity substation resulted in a blackout over the entire city that lasted for more than 24 hours. Suddenly people realised that, without electricity, there is no internet, no mobile phones, no contactless payment, no lifts and no petrol pumps. Although these dependencies were not difficult to see few had thought through the implications of losing so many aspects of modern life at once."

Some rural areas outages last for weeks. Then there are the issues when the UK's 2 days stores of gas are exhausted. At that point rotating planned outages occur, as we experienced in the 70s.

No point in asking VirginMedia about roadside cable repeaters or anything else, of course.

Newer FTTP Openreach connections go directly to the exchange. That leaves the ONT and modem in the customer premises. Both of those are powered by mains->12V bricks. Clearly in a prolonged outage it would be possible to use a car battery or AGM battery to supply the 12V; current 25mA-750mA for the ONT, 1A-1.5A for the modem. I'd use a tablet which can run for 8 hours on its internal battery, and use a 12V->USB adaptor to power USB devices.

Not sure what will happen when my village exchange closes in 2030. If the fibres already go directly to a central exchange, then probably not much. But I suspect there are some form of "concentrators" knocking around between the ?10000? houses and the exchanges.

Looking on Amazon there are UPSs for £100 or so. Giving it a cursory look over, I'd guess they could keep a normal PC going for about five minutes, enough time for an orderly shutdown or to complete a BIOS update. They could probably keep a cable modem and a low consumption computer, such as an SBC, going for much longer.

I was not amused to find my 3kW UPS takes 100W from the batteries even if there is no load. One of my principal uses for mains would be freezers. While 90W when running, they can take 1kW or so during startup.

Depends on what you are looking for. If you can tolerate a short interruption then it may be better to have a "portable power station" consisting of a lithium battery plus inverter, and simply move the mains plugs.

Conventional landlines are a vanishing thing these days. I'm pretty sure that in the old days, the phone system was run from batteries charged from the mains, so in the event of a power outage they could continue for a long time.

Correct. Large numbers of batteries under the floor. Not sure whether they were lead-acid or NiFe.

[EC8010]

Exchanges had dirty great lead-acid batteries, with each cell the size of a domestic washing machine. Nominal voltage around the exchange was 48V, distributed by dirty great aluminium bus bars near the ceiling.

[tggzzz]

Exchanges had dirty great lead-acid batteries, with each cell the size of a domestic washing machine. Nominal voltage around the exchange was 48V, distributed by dirty great aluminium bus bars near the ceiling.

Also 48V on the lines to customer premises; current limited, of course. 48V was deemed to be non-hazardous if touched.

I heard stories about not wanting to drop a wrench on the busbars

[Zenith]

Exchanges had dirty great lead-acid batteries, with each cell the size of a domestic washing machine. Nominal voltage around the exchange was 48V, distributed by dirty great aluminium bus bars near the ceiling.

Also 48V on the lines to customer premises; current limited, of course. 48V was deemed to be non-hazardous if touched.

I heard stories about not wanting to drop a wrench on the busbars

I recall the ring tone was 75V AC (@ 15HZ??) and was produced by dynamotors.

I knew someone who was working on his car and laid down a big spanner - across the terminals of a new, fully charged car battery. The battery exploded. He was lucky to escape uninjured. Slightly differently, there was someone I was at school with who helped another ex-schoolmate repair the fuel tank of a TVO powered tractor by soldering it. TVO was a something like a mixture of paraffin and petrol. The tank exploded and blew the roof off the shed. Once again they were lucky and escaped without serious injury.

[EC8010]

Yes, there were strict rules about what could and couldn't be taken into battery rooms. No jewelry and (especially) no metal watch straps. Putting the bus bars near the ceiling made it harder to drop spanners on them. I never worked in a battery room, but I would expect there also to be rules about the sort of tools that could be taken in there. I would expect spanners and the like to be single-ended and insulated for their entire handle. The other issue is that charging batteries can produce explosive gas, so no smoking, either. Changing the subject slightly, if you read any 50s fiction (Nevil Shute, HG Wells, John Wyndham) all the characters smoke like chimneys.

Ring tone was 17c/s (Hz hadn't been invented) and in small installations produced by a Syncycle which divided mains frequency by three and produced 90VRMS. You knew about it if you worked on a frame to move jumpers and someone rang while you were connected. Once upon a time, I knew how a Syncycle worked, but it had no moving parts and relied on saturable inductors. It was 2U high and about 5" deep on a 19" frame. Oh, and to complete the dangerous voltages, there was telegraph, which was a +/-80V square wave. Repeater amplifiers for telegraph were mercury-wetted relays.

Noting Zenith's comments, you need to be very careful around batteries and fuel tanks. I short-listed for a Darwin award as a child by testing for a spark on the cleanest bit of metal I could find - the opening of the lawnmower's fuel tank with the cap removed; there was no spark.

[Zenith]

I was not amused to find my 3kW UPS takes 100W from the batteries even if there is no load. One of my principal uses for mains would be freezers. While 90W when running, they can take 1kW or so during startup.

It's not clear to me what's going on here. Do the freezers take 1kW for a second or two while the motor starts, or do they take 1kW while the motor is running and dropping the temperature? How many freezers? What are the consequences of overtaxing the UPS? Will it just refuse to play, or will it be damaged?

I'd say it needs a management system so not all freezers can start (or run) at the same time, with relays to isolate them at will. Such a thing may be commercially available, or could be a project.

The local shop was talked into buying several air conditioning units, which looked like overkill. They asked me why the main trip was being thrown randomly. Well, they had a lot of lights and the till and camera system drawing power all the time. It was hot weather. They had several freezers and chilled units switching on randomly and the air conditioning doing the same. There was bound to be a time when most or all of these were switched on together and so the main trip would go. Solutions included getting an upgraded mains supply, expensive, having fewer air conditioning units, or some management system to deal with demand. They now have one air conditioning unit and no problems.

[tggzzz]

I was not amused to find my 3kW UPS takes 100W from the batteries even if there is no load. One of my principal uses for mains would be freezers. While 90W when running, they can take 1kW or so during startup.

It's not clear to me what's going on here. Do the freezers take 1kW for a second or two while the motor starts, or do they take 1kW while the motor is running and dropping the temperature? How many freezers? What are the consequences of overtaxing the UPS? Will it just refuse to play, or will it be damaged?

For a single chest freezer the normal power consumption while motor is running is ~100W; that's as shown in the documentation.

For ~100ms to ~1000ms when the motor starts, the power consumption is from 250W to 1kW. I found no correlation between time and peak power and any other condition. I do not understand either the duration nor the peak; both seem excessive.

An overcurrent condition is detected, and shuts down without damage.

A ferro-resonant transformer merely makes it worse, since that predictably draws a lot of current when switched on. No surprises there.

[Zenith]

Then assuming you have half a dozen of these freezers, all in their working temperature range and switching on and off semi-randomly, and there's a power cut and the UPS takes over, you only have a problem if more than two decide to switch on in the same short (approx 1 second) period, which on the face of it is highly unlikely. You could gather stats on the way they turn on and off and quantify the risk. IMHO it's not worth the trouble.

[tggzzz]

The problem arises in two cases.

Firstly if you have a 500W UPS for a single freezer. Looks OK on paper, but doesn't work.

Secondly if there is a prolonged power cut during which the temperature of several freezers rises to, say, -15C. Then all the motors will switch on simultaneously - and might even pop a circuit breaker in the central fuse box.

Solution to the latter is obviously to unplug all but one freezer, reset the breaker/fuse, and then plug in each freezer one at a time. I've warned my daughter she might have to do that.

[AVGresponding]

My free-standing worktop height one uses less than 100W with the compressor motor running. Be careful if you plan to run one on a UPS; the motors don't like modified sine or square waves, they cause too many I²R losses and consequently overheat.
I'm guessing 1kW is a momentary inrush? Most UPS's/inverters can handle 2-3x rating for a few milliseconds without a problem.

100W while idling is pretty normal; you've got a 3KVA transformer to keep energised, and if it's a consumer/low end commercial grade unit it'll be running on quite a low DC voltage so it has a lot of work to do in the primary.

I helped replace a couple of battery shelves at the Kearsley telephone switch in the 1990s. At that time, they were using a large room filled with shelves of SLA batteries, 38Ah ones in many paralleled strings of 4. Each shelf contained 2 tonnes of batteries IIRC, and there would have been a dozen or so.

[youtube]https://www.youtube.com/watch?v=DpQeDcEpEn0&t=127s[/youtube]

[Zenith]

For the first problem there just has to be adequate UPS backup.

For the second problem, some sort of monitoring and staggered start and alarm system. For instance, she might be on holiday abroad or somewhere far flung in the UK. Just an alarm system would enable someone - you? - to go across and sort things out before everything spoiled.