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Helston Revisited


Andy Keane
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35 minutes ago, Andy Keane said:

Phil

I have MERG current sensors literally on every section of my layout - so far thats 28 in the fiddle yard and I put in 8 more today on the first station board with another 20 or so to go - these all talk to JMRI so my tracks light up as things move around - see below (two lasers and 16 occupancy sensors talking to an Arduino Mega linked to the NCE bus) - its not pretty but it all works fine. But for automation I need more precise position inputs so in the fiddle yard I have the lasers as in the photo. But in the station these would be too obtrusive so I am going with undertrack active IR. I am debating on exactly where to put them but they will link into the Arduinos alongside the MERG current sensors. Its probably overkill but it needs doing while I am laying and wiring tyrack even if I don't in the end use it.

regards

Andy

20220302_214735.jpg.cf07d97de2dc089147cc3de5ceea7ee5.jpg

 

The advantage of current sensing is that it is completely invisible and won't get interference from ambient sources like bright sunlight.

 

Isn't precise position input using current sensing just a question of more (smaller) isolated sections of track?

 

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Phil,

My key requirement for automation is to be able to have a train stop, decouple the loco, run around, recouple and leave again. In the fiddle yard the lasers give me fine precision. But I want to ensure that my loco stops in the station platform with its coupling over the eltro-magnet that will release my Kadees. for that I need accuracy to around plus / minus an inch. I suppose I could make the section with the doucoupler into a very small current sensing unit - I had not thought of doing that but now you have me thinking again - the great joy of this madness we engage in - I will let the grey cells work on your suggestion overnight. Maybe an experiment is called for.

Many thanks for your inputs which are much appreciated

Andy

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9 hours ago, Andy Keane said:

I suppose I could make the section with the doucoupler into a very small current sensing unit

Doesn’t need a ‘small’ section, it’s where the break between section is that defines the stopping point.  Then it’s loco length that says where the uncoupler is.  Different length locos will need different stopping positions.

Paul.

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3 hours ago, 5BarVT said:

Doesn’t need a ‘small’ section, it’s where the break between section is that defines the stopping point.  Then it’s loco length that says where the uncoupler is.  Different length locos will need different stopping positions.

Paul.

Ok - I think I see. When the loco enters the section before the uncoupler we slow to a crawl. Then when the loco crosses into the new section and both the old section says its left and the new one says its arrived we apply the final brakes. We just need the section break to allign with our desired stopping point. Hopefully the train stops almost immediately so we know where its rear end is. And because we check for the old section to clear provided we have pickups on wheels at the ends of the loco its length will not matter  too much. So on my tank engines length is probably not too critical but if running a tender loco in reverse with tender based pickups only it would get it wrong. But I could probably fix this by adding contacts to the driving wheels on such locos. I modified my Bachmann Mogul so it has pickups on both tender wheels and main driving wheels so it would be like a tank engine in that regard. Alternatively the automation code would need to know which loco it was dealing with and allow a slight delay on final stopping. I can see much fun ahead!

Andy

ps - you are up early!

Edited by Andy Keane
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"Fun" or "Pain"? Maybe this is not such a good idea.

 

 

You really want to know the position of the couplings rather than the locos... And you really want to measure those positions changing, not just have a binary notification that it has reached a certain point...

 

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8 hours ago, Andy Keane said:

ps - you are up early!

Early flight!  I do it about once per year, those on checkin etc probably do it one week in three.  Respect.

Paul.

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Have pottered away this weekend putting the wiring for the station throat board. Motors and DCC wiring in. Just the Arduino to configure and add plus three controllers for the signals, also the 16v DC supply that will provide power for the Arduino and various elements of lighting (loco shed and yard lamps etc). Still undecided about adding IR track sensors in the loco and head siding on this board. Not really sure I would actually use them.

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20220508_195231.jpg.8a5f549c56974e8ecd832ae3f7b55ac8.jpg

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1 hour ago, Graham T said:

Impressive stuff Andy (and very neatly done), although I must confess that I don't know what half of it is!

I have a habit of engineering the simplicity out of things!

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4 minutes ago, Andy Keane said:

I am off to expoEM in Bracknell this Sunday to help with the Missenden stand. Will anybody else be going?

I shall be sat next to you....sorry...

Chris....

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On 10/05/2022 at 16:46, Andy Keane said:

A bit of loco painting and relettering.

20220510_155234.jpg.57de89340858463d229ce524200887a7.jpg

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I have been looking at the photos of 44/45xx locos in J.H. Russell's two volume pictorial record of GW engines and none of them shows the yellow route letter on the cab. Does this mean in fact these engines were unrestricted? I had planned to add a route disc but now I think I will not bother. What I really need is a colour photo of a dirty 44/45xx or a 14/48xx to base my weathering on if anybody knows of any.

Andy

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46 minutes ago, Andy Keane said:

I have been looking at the photos of 44/45xx locos in J.H. Russell's two volume pictorial record of GW engines and none of them shows the yellow route letter on the cab. Does this mean in fact these engines were unrestricted? I had planned to add a route disc but now I think I will not bother. What I really need is a colour photo of a dirty 44/45xx or a 14/48xx to base my weathering on if anybody knows of any.

Andy

There are a few period photos of 48xx in Neil Dimmer's collection here: 

4855 unknown location

 

(Mostly BR era though and very few in colour.)

 

45xx's in another folder.

 

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I have popped a frog juicer (from www.blocksignalling.co.uk ) onto point 8 in the station so it frees up the switch on the DCC Concepts point motor that I would normally switch the frog with. This will then be used to switch between the two lever four ground signals as per the signalling diagrams so the twoi signals can be workerd from a single lever / DCC accessory code. I have not used juicers before so will be interested to see how they work. And I have yet to get a working ground signal up and running either.

Andy

20220514_103851.jpg.1f6461dea1d3d34a3787cdf0d94f7ddd.jpg

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That will be interesting to see how it all comes together Andy.

 

Will the ground signal be servo controlled? I’m surprised there isn’t a steam era RTR ground signal yet.

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2 hours ago, Neal Ball said:

 

Will the ground signal be servo controlled? I’m surprised there isn’t a steam era RTR ground signal yet.

 

If we're lucky perhaps Dapol will do the honours?

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56 minutes ago, Graham T said:

 

If we're lucky perhaps Dapol will do the honours?


Yes…. But….

 

On adjacent lines, there might not be enough space to get their huge mech under the board!

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