cliff park

The phrase 'Hall effect switch' is all embracing for a family of devices. The most basic can be thought of as a transistor which is turned on by a magnet. The more complex ones are integrated circuits which can include op-amps and latching circuitry. Even the basic one should be able to light an LED or operate a relay with the right circuit.

If you position a permanent magnet parallel to the reed but just far enough away not to operate it then only magnets the right way round, reinforcing the weak one, will operate it. So with two reeds you could achieve what you want. The two reeds could be side by side,, with the biassing magnets placed one each side.

My dad bought two vans to store building materials, back in the late sixties, and found a firm that supplied corrugated iron sheets curved to fit the roof. They are still in use today, if a little dilapidated, and no longer storing building materials, just garden stuff.

A quick vote for white vinegar. In the middle of the first lockdown I was given a woodturning lathe which had been left on a bench below a leaking shed roof for about 3 years. I stripped it all down, left it all in plastic tubs to soak for several hours, and it all came up beautifully, with no damage to plastic parts.

Can anybody identify this? A friend, retired carpenter, found this when tidying his workshop. He says he has no idea what it is, or where he got it from. The body and handle are wood, possibly rosewood. The other prong, the one without the crocodile clip appears to be broken off. All three screws have pointed ends. I have yet to see this in person, working from this:-

Harlequin is of course right, but just in case you are very new to this I will explain further. The frog, see sketch. can be part of each way of the point. So sometimes it needs to be connected to the A rail, and sometimes the B . The aim of the switch is to make this controlled by the point motor, and reliably connected to the right rail

We have something similar run by Norfolk County Council. Try this link http://www.historic-maps.norfolk.gov.uk/mapexplorer/ . It may come up with an error about non-secure link, but it works fine. Obviously it only covers Norfolk, back to tithe maps, but there could well be similar maps from other councils, I don't know how you would find them.

DIN plugs and sockets were originally intended for low power audio signals, and as such are not ideal for power. They also have small pins for soldering. SLR connectors are designed for power and have solder buckets and more space between pins, all making life much easier.

May I just tell the story (almost certainly apocryphal ) of the young man whose father was the village wheelwright and carpenter. The young man was drafted into the army and became an engineer. Home on leave he was explaining to his father how they made parts accurate to within 5 thousandths of an inch !!! His dad calmly replies "when I make something, I make it exact"

I don't understand the comment about drilling being a problem. When working chipboard always use sharp tools. I have been using chipboard in some projects in conjunction with a charity I run, and I was given 4 sheets, 12mm, 8' X3', (yes 3' for some reason). So I do have some experience. Your main concern is keeping it dry, and , importantly, this includes the question of how you ballast the track. You do not want to be sloshing water on it. Sometimes if you are heavy handed with PVA when gluing you can see it start to soak in before it dries. I suppose one option would be to do all the sawing, drilling etc that you can then seal it with something like oil based paint, liberally brushed all over, both sides and particularly the edges. Check your local waste tip, they sometimes have odd tins of paint very cheap, and the colour is irrelevant, although green or brown might be good. I do think that newer chipboard is better than the stuff I remember from childhood, and my dad was a carpenter so I did see plenty, finer chips and better glue now.

Little Snoring is actually a village in Norfolk, about 2 miles East of Fakenham.

In the waste recycling centres the different plastics are identified by firing a laser at them. Different plastics return different combinations of frequencies. Do you remember up until quite recently raw meat came on black trays ? These had to be discontinued when the lasers came in because they reflected none of the the light and all went to landfill, despite the plastic being recyclable. Not sure that the machines can deal with the small pieces we are dealing with here though.

I think the creeping banner adverts were designed by somebody with a warped mind. It is almost impossible to click on the 'last post' button while it is creeping down the screen. If anything it makes me promise NEVER to have anything to do with the advertised company because they annoy me so much. I seriously think I will have to cancel my membership, it is all getting too much

Just in case it helps, MDF will reliably take a thread. Obviously not for heavy loads, nor for repeated screwing in and out, but for an assembly like this it would be better than woodscrews

I have in the past used a drop shelf instead of a raised one. Obviously the shelf length must be less than the floor to layout height. It does restrict the doorway by the thickness of the shelf, say 4", and it helps if there is nothing sticking up on the top of the shelf, say telegraph poles, loading gauges or buildings. But for the 'tidal creek ' I would have thought it would work well. The barrel bolts can also be used to operate a relay so that when the shelf is down track either side of the shelf is dead

I have tried to put some notes together to answer the kind of questions that come up for people who have no electronics experience. LEDs and resistors are cheap. You can experiment without worrying what it will cost. Resistors are robust, mechanically and electrically, LEDs are not. LEDs can be destroyed by heat, don't solder too close to the body, and don't keep the iron there for too long. A good idea is to use chocolate blocks to try different resistor values, and solder once you're happy. LEDs are polarity sensitive, resistors are not. It does not matter a scrap which leg of the LED the resistor is in, BUT if you always put it in the same leg it makes life easier when wiring them up. LEDs with a resistor in series will not be harmed if connected the wrong way round, they just won't light up. Resistors are measured in Ohms, symbol Ω. If using resistors in series simply add the values together, so a 10KΩ (ten thousand ohm) plus a 10KΩ in series equals 20KΩ. Putting resistors in parallel is more complicated, but for this simple example a 10KΩ and a 10KΩ in parallel equals 5KΩ. Resistors come in preferred values. So you will not find a 5KΩ resistor, you must use 4·7KΩ or 5·6KΩ, but don't worry, when it comes to LED brightness those difference will not make a huge difference. You will almost certainly only ever need ¼ watt, the power rating, as the current used by LEDs is very small. Start off with high value resistors, the LED will be dim, reduce the resistance until it looks about right. Don't forget an LED sitting on the bench looks different once installed into a building.

As another (retired) electronics engineer I suspect that the sledgehammer brigade are just frightened of things they don't understand. I have told this story on here before. My first experience with a PAT guy was when we brought in external contractors, instead of doing it ourselves. He cut the mains plugs off half a dozen monitors and condemned them because there was no earth continuity to a metal screw he found in the case. They were all double earthed with no earth connection.

When I worked in the tech department of a high school we had lots of problems with photos of projects stuck into folders then having to be sent away for adjudication. On arrival lots of the photos had come free from the folders. After experimenting we found that of all the available brands Pritt Stick was the best and lasted the longest. Eventually, about 3 years, even they dried up, but that was paper on paper.

Maybe these ?

Saturday was market day in Norwich in the 1950s, I can remember as a child vast numbers of cattle being herded through the streets down to Trowse station to be loaded on the trains. I assume it had always been Saturday.

Not easy to see your circle, so if you don't mind I have highlighted it

They certainly use that trick to spray car panels and other metal parts. A place near us specialises in spray painting office furniture, frames for school desks etc, and I've seen that in action. Quite remarkable the way the paint is attracted to the metal.

Just noticed this post. Try asking in the 'Electrics non-DCC' forum. Lots of stuff on HM6000 units there

So the BT one and the APD one together add up to 1.15A approx. But this is only when 'loaded 'up. Ie most of the time they take negligible current. It wouldn't hurt to uprate your cable if you have multiple sockets, there is always the chance somebody will plug a fan heater or something similar in, or at least make sure the fuse in the plug is 3Amp.