E2e's 2017 4 Wheel Coach Competition Entry

[Roger (RJ)]

Board layout and circuit looks OK to me. The bridge rectifier takes care of reverse polarity on the input from the track.

[TimberSurf]

You have the 1k resistor after the bridge rectifier! I thought it was before, on the AC side (to act as a voltage dropper, as the AC voltage is too high)
Wait till you get the components before designing veroboard layout (may not be the size you expect)
You may be able to fit bridge rectifier like a diamond (only 1 cut needed)
The capacitor is "Polarity sensitive", ensure + on it goes to positive
2 wires do not go into 1 hole - light bar negative and link need to be on 2 different holes (you would have worked that out at the construction phase, but plenty of spare holes to choose from)
@alex3410 - polarity on ac does not matter, rotating carriage will have no effect

[End2end]

Thanks for the confirmation Roger So it doesn't matter which way round on the track they go either. Great stuff!
Hopefully I will have something to show in the next few days once the postie brings me the final pieces
Thanks
End2end

[End2end]

A little more explanation needed I think.

You have the 1k resistor after the bridge rectifier! I thought it was before, on the AC side (to act as a voltage dropper, as the AC voltage is too high)

Ahh I was going by this diagram in this video https://www.youtube.com/watch?v=JiZ6Jj3OoK8

EJcircuit.JPG (10.95 KiB) Viewed 3167 times

Wait till you get the components before designing veroboard layout (may not be the size you expect)

In my drawing I have used 6 x 6 but I can go upto 8 holes wide and 14 holes long but this length would lower the capacitor under the coach so there is some room to grow the board if I need to. It was more a case of "how can I make my original 8 x 14 board smaller?

You may be able to fit bridge rectifier like a diamond (only 1 cut needed)

The bridge rectifier is actually circular. I made it square in the drawing just for my benefit but this is the part I'm waiting for at the moment.

The capacitor is "Polarity sensitive", ensure + on it goes to positive

Will do

2 wires do not go into 1 hole - light bar negative and link need to be on 2 different holes (you would have worked that out at the construction phase, but plenty of spare holes to choose from)

Funny about this one Timbersurf.
As the 4 wheelers have holes in the floor either side in the middle of the length of the coach where I will push up the wires, I can move the output wires to the lighting bar by one hole on the positive and a choice of 5 holes for the negative and still be close enough to the wiring holes in the coach. I think that's going to make it much easier.

If anything is wrong please do point it out.
Thanks
End2end

[TimberSurf]

Leave the resistor as you have shown. I have seen it on the AC side before, but its probably better after, as it will limit the inrush to the cap on power up.
Rotating the "round" bridge rectifier by 45 degrees, so in plan view, leads form a diamond, can sometimes orientate the tracks for easier access.
If the Capacitor is not mounted on the board (not tight, but with some leads left long), you can probably fit it on 4x4! (also depends if you have ordered axial or radial lead type)
It's hard to imagine exactly were on the carriage you intend to put the electronics, but I still think loosing the veroboard and wiring the components to each other may yet have some merit, if you are really stuck for space.

[End2end]

Thanks for the reply Timbersurf.

It's hard to imagine exactly were on the carriage you intend to put the electronics

Underneath the coach in between the running boards. Theres a large void where a more detailed wagon or coach would have it's gubbins. It has some small diagonal supports (IN BLUE) at the side that almost split the bottom up into 3 areas. The largest, middle part (RED BOX) being big enough for ther 8 x 14 board but the actual full length of the void (YELLOW BOX) is 67mm. Unfortunatly it would make anything underneath the coach lower because of the diagonal supports if the whole void were to be used and would also hit the axles or wheels.

4WCInteriors19b.JPG (78.98 KiB) Viewed 3158 times

Thanks
End2end

[End2end]

OK so moving on.
Firstly temporarily pushing some of the componants through a larger board to make sure everything fits as in my 6 x 6 hole diagram.

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Then seeing how each will fit on the 6 x 6 hole boards.

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Drilling out some holes on the rear of the vero board, cutting the tracks to isolate some of them for the rectifier.

4WCElectronics3sm.JPG (27.2 KiB) Viewed 3142 times

Making sure alongside my diagram. (This is the rear of the board so the track cuts are mirrored to the diagram)

4WCElectronics4sm.JPG (41.56 KiB) Viewed 3142 times

Adding the rectifier.

4WCElectronics5sm.JPG (35.88 KiB) Viewed 3142 times

More to follow....

[End2end]

A close up of the positions of the rectifier and resistor.

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The legs of the rectifier and where it will be soldered.

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2 pictures with the capacitor now also soldered in place.

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4WCElectronics9sm.JPG (33.8 KiB) Viewed 3142 times

Next to add is the pick up springs and make the wheels conductive.
Thanks
End2end

[End2end]

So now onto making the wheels conductive. I did toy with the idea of conductive paint but went with a much simpler design of using kitchen / tin foil.
So first off I had to remove one of the wheels from the axle. This is easily done if you have a back to back gauge by standing the axle on its end and excerting pressure downwards on the lower wheel. Sometimes the plastic bush gets stuck on the axle so may need pulling off seperatly once the wheel has come off.

4WCWheels1sm.JPG (27.6 KiB) Viewed 3141 times

Here it is seperated into the componant parts I need including the small black bush. The metal rod that can be seen is actually an old metal clothes hanger I cut up and fits perfectly into the middle of the wheel to push out the bush.

4WCWheels3sm.JPG (28.82 KiB) Viewed 3141 times

The next 3 pictures show the method for adding the kitchen / tin foil.
Firstly the small strip can be seen at the bottom of the picture.

4WCWheels4sm.JPG (25.06 KiB) Viewed 3141 times

Next the foil can be seen folded in half twice.

4WCWheels5sm.JPG (26.72 KiB) Viewed 3141 times

And the twice folded foil added to the bush by pushing half of it through the middle and folding the other half over the outside.

4WCWheels6sm.JPG (24.79 KiB) Viewed 3141 times

More to follow....

[End2end]

The foiled bush now gets pushed back into the wheel making sure both "legs" of the foil go through the hole.

4WCWheels7sm.JPG (26.19 KiB) Viewed 3141 times

Now pushed home in the wheel and the pick up spring added to the axle before reconstructing the full wheel set.

4WCWheels8sm.JPG (29.95 KiB) Viewed 3141 times

And the finished conductive wheel set with any excess foil removed from the outside of the wheel.

4WCWheels9sm.JPG (26.51 KiB) Viewed 3141 times

Now repeat, in my case 9 more times.
I hope the descriptions and pictures are easy to follow if you are considering adding "powered from track" lighting on DCC without a decoder.
One thing I have noticed is that I have a small common point (flat) screwdriver end on my soldering iron which seems a little too big for the job so if you have one I would reccommend trying this project with a pointed ended soldering iron instead.
Do please let us know if try this out and you have a pointed end soldering iron and how it works out.
Thanks
End2end

[Alex3410]

Fascinating stuff!

Looks rather fiddly but you have made a good job of it, have you tested the connectivity of the wheels with your mod? Just thought it might be an idea before you do the lot!

I have a fine tip for my iron but it never seems to get hot enough to melt anything, when i get around to trying this I might have to give it another try.

Thank you for all the photos and detailed write up it's really interesting to follow

[Dad-1]

Interesting 'stuff'
Looking forward to running tests.

Geoff T.

[Boïschaut]

Interesting 'stuff'
Looking forward to running tests.

Geoff T.

Me too !

[End2end]

have you tested the connectivity of the wheels with your mod? Just thought it might be an idea before you do the lot!
I have a fine tip for my iron but it never seems to get hot enough to melt anything, when i get around to trying this I might have to give it another try.
Thank you for all the photos and detailed write up it's really interesting to follow

Thanks for the comments members.
One thing I omitted from the description which is paramount. Make sure when replacing the wheels sets that they pick up power from SEPERATE TRACKS!
Just to reply to your posts alex. Yes the connectivity is fine although sometimes I get a buzzing noise when testing a newly made up coach but it's just where the solder has leaked onto another track on the vero board because of the big soldering iron tip and doesn't take long to fix.

I think you may need a hotter soldering iron. Mine runs at 400 degress-ish as it's a more pro Weller one. On some irons the tip dictates the temperature so if you have more tips perhaps try experiementing with them to see if any run hotter.

I now have 2 complete working coaches although they still need the passengers.
Thanks
End2end

[End2end]

I went digging in a box last night that I knew had a few loose coal wagons in but little did I realise that I had another 4 wheel coach in there totalling 6.
I will need to get more of the seats if I'm to complete a full rake of 6 as I used up all I had in the first 5 coaches but if not I will push on to get the 5 finished in time.......to win
I also made the decision to halt work on these until a new smaller solder tip turns up that I ordered last night. I think my tip is just slightly too big and thus the solder is leaking to other tracks on the vero board sometimes.
Coincidently in the box was also a Wimpy van which now has it's picture in the "And the next photo will have" thread as a red van was requested. viewtopic.php?f=26&t=15101&p=623451#p623451

Thanks
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