6. Interesting automation

A Forum that is covering a build of a South African N Gauge layout by Fidel Naidoo.
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Fidel Naidoo
Posts: 59
Joined: 18 Jul 2011, 12:44

6. Interesting automation

Post by Fidel Naidoo »

Good day !!!

I haven't posted anything for some time, because I haven't done much but debug, debug and debug for 4-8-4's and 2-8-4. There are two sets of points I have replaced twice, but the leading wheels seem unable to get through the curve side of the points with out a de-rail.

Finally, this week, my latching relays arrived. I plan to use some of these on the spot where my double tracks merge into a single to over the bridge. These relays with handle signalling and train control to avoid accidents, all automatically. Because I know nothing about them, except what their basic behaviour is, I laid out a small piece of track, and soldered up the wires to one relay to make auto reversal. Very simple operation.

48 second video here : http://www.youtube.com/watch?v=S0wvZNob ... e=youtu.be

( sorry about quality - had as an MP4, converted to swf ).
I can now measure current over the legs, and draw up a plan for my junction.

Two things about these : Damn difficult to buy, ( ordered from overseas ), and smaller than you think, so difficult to solder.
Fidel Naidoo
Posts: 59
Joined: 18 Jul 2011, 12:44

Re: Interesting automation

Post by Fidel Naidoo »

OK,

My head is hurting now, with figuring the wiring out......
But I think I've got it. The reed switches have to power rails, dis-power rails, change points, and cut out their opposite switches until the 'clear' switch is triggered once the train is back on double lines.
And I haven't even included signal operation, because I'll let the point motors pull threads to operate the semaphores.

When I've actually built and tested the circuit in this post, if anyone wants, I can publish a neat, detailed schematic.
SAM_0627.JPG
SAM_0627.JPG (182.26 KiB) Viewed 4001 times
Niel Wilson
Posts: 23
Joined: 23 Apr 2010, 13:14
Location: Gauteng, South Africa
Contact:

Re: Interesting automation

Post by Niel Wilson »

Nice work using the latching relay as an auto reversing unit. Back when I still had an DC layout I did the same thing with a double pole relay and a 555 Timer IC as an astable oscillator to flip the polarity.

Just a suggestion for your soldering problem with relay. Some of the smaller relays can be plugged into IC sockets. These are easier to solder to and also reduces the chance of damaging the relay. Also if something goes wrong with the relay you can easily replace the relay.

I'm not sure on the size of your relay or the pin layout would work with your relay.

Cheers,

Niel
Fidel Naidoo
Posts: 59
Joined: 18 Jul 2011, 12:44

Re: Interesting automation

Post by Fidel Naidoo »

Neil,

Thanks for the idea. I reckon I'm going to the electronic shop on Tuesday with a sample to see if they have some kind of socket for these. The relays have funny connectors. They look like feet, because they come out of the relay body vertically down, and then turn outward 90 degrees for about 2 mm. I can't picture the socket they are likely to fit into.
Niel Wilson
Posts: 23
Joined: 23 Apr 2010, 13:14
Location: Gauteng, South Africa
Contact:

Re: Interesting automation

Post by Niel Wilson »

Most relays I've dealt with have always had pins that come straight out of the bottom. No funny bends or anything. I can't say I've come across anything that would fit your type of relay.

Just for interest sakes, where did you get your relays from?
Fidel Naidoo
Posts: 59
Joined: 18 Jul 2011, 12:44

Re: Interesting automation

Post by Fidel Naidoo »

Neil,

The only place I could find them was RS components online. They have an enormous selection of items, I just knew that I wanted 12v double pulse, double throw, double coil latching relays.
These guys seem to have a warehouse, or despatch centre in Gauteng. What I wanted isn't kept in stock, I had to wait ( only 8 days ) for them to arrive from the UK. They automatically couriered them to me, but if you close by, you can avoid the courier fee and collect direct. Your socket idea makes much sense on all levels, and I saw that they had sockets as linked items on many relays, but not the type I bought.

In terms of the junction, I've now soldered everything together ( 3 latching relays ), and it works great, to a point. I was up early to sort the problem out, and then I realised that I had made one small logic mistake ( but a very obvious one ), but that's easily solved with another relay.
Niel Wilson
Posts: 23
Joined: 23 Apr 2010, 13:14
Location: Gauteng, South Africa
Contact:

Re: Interesting automation

Post by Niel Wilson »

Fidel,

Thanks I'll take a look at RS Components next time I'm looking for some odd stuff like latching relays. These aren't something I've used before so not sure if either of my "local stores" stock them.

Thanks again
Fidel Naidoo
Posts: 59
Joined: 18 Jul 2011, 12:44

Re: 6. Interesting automation

Post by Fidel Naidoo »

Here is the finished product ..........
Z999.jpg
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The amazing thing is, it works !!
I ran into hassles with getting the two points to switch at the same time, so I looked the solution up, and found out about capacitor discharge units. Peco makes one, but I found that my 21 bucks spent on the components at the Electronic shop was better. The simple CDU is on the left side of the photo.
The logic unit has 4 latching relays, and three normal relays to perfectly control the single track where the girder bridge is going to be. Obviously, the unit won't stay on top there forever, I just want to test it completely before I hide it away.

I'll post a short video soon of it in action.
Kevin Wilson-Smith

Re: 6. Interesting automation

Post by Kevin Wilson-Smith »

Clever idea - look forward to the video!
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