Use of dccconcepts wiper pickups for coach occupancy detection

[G.M.R.]

I wonder if anyone has tried this?

 

I have just purchased a pack of the wipers with the intention of using them on the trailing bogies of my passenger trains to help with complete detection of occupancy within a block. They are very simple to fit, and easily allow the inclusion of a suitable resistor, but ....

 

The pickups are very stiff, so they apply a lot of friction which has the tendency of stopping the wheels rotating. They could be bent inwards but that may defeat the spring of the contact. Maybe others have found a way to make this work.

 

Otherwise I might try the surface resistor and conductive paint method instead.

[john dew]

Quite the coincidence.......my little parcel from Australia arrived yesterday.

 

I will be interested to hear how you get on. I bought mine to use as tender pick ups and for my experimental trial with the précis-models uncoupler.

 

Bit worrying to hear they that they create drag......the blurb claimed there was virtually no friction.

 

For occupancy detection I have used resistive wheel sets for many years.......works very well and significantly cheaper than the pick ups

 

Kind regards

 

John

[G.M.R.]

Quite the coincidence.......my little parcel from Australia arrived yesterday.

I will be interested to hear how you get on. I bought mine to use as tender pick ups and for my experimental trial with the précis-models uncoupler.

Bit worrying to hear they that they create drag......the blurb claimed there was virtually no friction.

For occupancy detection I have used resistive wheel sets for many years.......works very well and significantly cheaper than the pick ups

Kind regards

John

Hi John, long time since we chatted. I've been working on a fully automated set of signals for one of my junctions. 12 arms controlled by servos and several multiple aspect coloured light signals. An Arduino then monitors a number of turnouts and occupancy detectors to enable the signals. Hence the need to be able to detect the end of each train. One day I might splash out on a full copy of RR&Co and use the computer, but for now I continue to enjoy handling things with electronics.

 

I will be interested to see how you get on with the pickups.

 

I've just placed an order with rs for the resistors and paint.

[Ian Abel]

Thanks to both the OP and John.

Useful/timely post, even if it IS somewhat disconcerting. I was/am just about to place an order for the exact same purpose as John, i.e. wanting to add some tender pickup to a few locos that don't have that feature.

 

Additionally, I was hoping to use them on a couple of 2-BIL trailing cars as I want to add lighting to the 2-BILs I have and would like the added "security" of additional pickup even though I intend to wire the lighting from the 2-function motor decoder I installed. Figured if I was running wires between the cars anyway, I'd add some additional pickups...

 

Will watch with interest as the friction issue develops and is discussed/overcome.

[roundhouse]

I picked some N scale wire pick ups from DCC Supplies a while ago and fitted them to both driving cab units for fitting headlights on a Farish 168. Hardly any drag at all. Can't remember the name but they do them in HO / 00 scale aswell.

[G.M.R.]

Here is one installed on my test coach, which is a Hornby Gresley:-

 

 

It works, but the friction is sufficient to stop the wheels turning so they are dragged along the track. Bending the wipers inwards corrects this, but then the side to side movement of the wheel set in their end bearings causes the wipers to intermittently lose contact.

 

Unless I'm doing something wrong. I'm not impressed.

[uax6]

Can you not use them as a basis for a little mod? I would get some ph/bronze wire, wrap it around a 2mm drill bit to form a single loop, and make sure that the ends are at 90* to each other. Solder one end to the DCC concepts wire, and the other against the edge of the flange. The loop will allow the wire to spring gently against the flange, so good pick-up and no skidding.

 

Andy G

[john dew]

Hi Geoff

 

It took a while for the penny to drop ........I had to check your profile ( you sound remarkably spritely at 101 years of age) before I realised you were my old electrical tutor on YMR and MRC.......I have often wondered about you......I just assumed your golf handicap had come down to single figures!

 

How is Mangarth coming along.......my last recollection is of the shed complex you were developing to showcase your A4s.

 

It's a pain about the pick ups.....kind of defeats the purpose .....later today I will fit one to the Toad BV that I am going to trial the uncoupler on......even if I don't set up the decoder at least I will get an idea of friction

 

Best. Wishes from a damp Vancouver

 

John

[Phil Bullock]

I make my own for tail lamp pick ups with lengths of .45mm NS wire soldered to a length of copper clad sleeper which I then superglue in to place

 

Arms are long enough to minimise drag whilst following side play in wheels

 

Wire is bent to a W shape, centre is soldered to CCS, outer arms of W are truncated, the points of the W bear on the inside of the wheels

 

Phil

[G.M.R.]

I make my own for tail lamp pick ups with lengths of .45mm NS wire soldered to a length of copper clad sleeper which I then superglue in to placeArms are long enough to minimise drag whilst following side play in wheelsWire is bent to a W shape, centre is soldered to CCS, outer arms of W are truncated, the points of the W bear on the inside of the wheelsPhil

Wish I had asked before I splashed out the £25 for these high quality parts. I've turned it around and added 0.45mm n/s wire more or less as you describe, Phil.

 

 

Works a treat. I can even spin the wheels a little. It runs along the block with no interruption to the detection from my recently acquired DBD22 current transformer detectors.

 

Thanks.

 

By the way if anyone else intends using these on plastic frames or bogies. Attach the wires or components first. The solder tags go right through, so I managed to melt the plastic under the body of the mount. Using CCS would not only be much cheaper, but would also not exhibit this problem!

[G.M.R.]

Hi Geoff

It took a while for the penny to drop ........I had to check your profile ( you sound remarkably spritely at 101 years of age) before I realised you were my old electrical tutor on YMR and MRC.......I have often wondered about you......I just assumed your golf handicap had come down to single figures!

How is Mangarth coming along.......my last recollection is of the shed complex you were developing to showcase your A4s.

It's a pain about the pick ups.....kind of defeats the purpose .....later today I will fit one to the Toad BV that I am going to trial the uncoupler on......even if I don't set up the decoder at least I will get an idea of friction

Best. Wishes from a damp Vancouver

John

Still playing a lot of golf, but also been able to continue to develop Mangarth. Signal activity posted here http://www.rmweb.co.uk/community/index.php?/topic/104284-new-signals-for-my-layout/

 

I have only recently come back to the forum so ought to update my old layout post with the current state of the layout.

[Phil Bullock]

Glad you found that useful Geoff

 

Also use a very similar arrangement to deal with the current collection issues on the current Bachmann 40s and Warships

 

Phil

[melmerby]

Bit of pcb and some springy wire.

 

I would never pay good money for that, I would just do it myself, as no doubt would many RMWebbers!

I have already done that on the trailing bogie for a Lima Railcar (And on the bogie of a K's Autotrailer) - maybe I should sue DCC Concepts for nicking my idea! (and everybody else's)

 

Keith

[Nigelcliffe]

Phos-bronze wire will be better than NS.  It can also be improved in "springiness" by adding a small 360 degree loop in the length of wire (wind it around a small drill bit). 

 

An alternative method is fix the resistor to the axle, and thus the scraper/drag pickup can be eliminated.  Use of conductive paint to complete circuits can help.  "Metal film" resistors are generally smaller body than "carbon film" so won't be so bulky along the axle, or surface mount resistors may also work for some people.

 

 

- Nigel

[RAF96]

I've used the springy phosphor bronze strips robbed from Hornby's nasty little track power clips to make axle wipers to pick up current for coach lighting using Hornby Pullman wheel sets, which are live axle to one wheel and the other wheel insulated..

 

They are in two lengths (nearside rail and far side rail) so you can use them to rub on one or two axles of a bogie set - just make sure you have your live wheels/axle set  to left and/or right as appropriate to preclude shorts.

 

Hornby's other replacement metal wheel sets have both wheels insulated from the axle so you then have to resort to wheel scrapers for power pickup.

[Mike Friedman]

If you just want resistive wheel sets for block detection I found the simplest method was using the largest surface mount resistors (the largest of three available sizes).

 

As Nigel mentioned these can be attached with superglue bridging the plastic axle to wheel insulation, then a dab of conductive paint ensures good conductivity and the job is done:

 

[G.M.R.]

If you just want resistive wheel sets for block detection I found the simplest method was using the largest surface mount resistors (the largest of three available sizes).

 

As Nigel mentioned these can be attached with superglue bridging the plastic axle to wheel insulation, then a dab of conductive paint ensures good conductivity and the job is done:

 

 

ResistorDs.jpg

Thanks for the photo. I've had a couple of goes and both provide the necessary resistance. The first was with a little heat shrink on the axle with the resistor horizontal. The second after I saw your photo done your way with the resistor vertical. Much easier, so that's the way I will use.

 

 

The one on the right is the vertical one. My photos not a patch on yours.

 

Thanks again.

[melmerby]

 

If you just want resistive wheel sets for block detection I found the simplest method was using the largest surface mount resistors (the largest of three available sizes).

 

As Nigel mentioned these can be attached with superglue bridging the plastic axle to wheel insulation, then a dab of conductive paint ensures good conductivity and the job is done:

 

 

 

I see you have used 4700 ohm resistors was that value arrived by experiment?

Is that just one per vehicle?

 

Another way to get contact if you are using 14mm coach wheels:

A lot of Hornby wheels have a solid wheel one side only, (used for coaches with lights) if you reverse one axle you can wipe against the axles with phospor bronze wires (one to each) with little friction putting a suitable resistor between the two wires.

 

Regards

Keith

[G.M.R.]

Keith, 4k7 is recommended by the makers of the DBD22 current transformer detectors that I have. One per car should be fine.

[RFS]

G.M.R., on 13 Feb 2016 - 19:17, said:

Keith, 4k7 is recommended by the makers of the DBD22 current transformer detectors that I have. One per car should be fine.

 

I would suggest two per vehicle - especially for ones at the end of the train.  Otherwise one dirty wheel could lead to the vehicle being invisible.

[melmerby]

I would suggest two per vehicle - especially for ones at the end of the train.  Otherwise one dirty wheel could lead to the vehicle being invisible.

I'm using RS-8s so I think a little experimenting is in order.

IIRC when testing the units they trigger with as high a value as about 12K

 

Cheers

 

Keith

 

EDIT

Just got another RS-8 kit out to assemble.

The specification trigger current is 1mA so my 12k would be about right.

[peach james]

I think with Digitrax stuff, I am running 10k per axle, and 2 axles on "known" EOT things- brake's.  Some of my wagons have been fitted as well, to keep detection within sections active on long trains.  It does no good to free up the section under the train, otherwise bad things happen...

 

Also remember to set however you use your detection to provide a 2-3 second delay on clear, I find it really helps with keeping constant detection values.   I'm still using RR&Co 5.0c.5 because I refuse to spend more money on something "new" that doesn't appear to be much better to me...

 

James

[Dagworth]

Rather than adding surface mount resistors or wiper pick-ups and resistors I use Uhlenbrock resistive paint.

http://www.aandhmodels.co.uk/uhlenbrock-40410-resistive-laquer-9303-p.asp

 

You can do hundreds of wheelsets in an evening!

 

Andi

[Dagworth]

I think with Digitrax stuff, I am running 10k per axle, and 2 axles on "known" EOT things- brake's.  Some of my wagons have been fitted as well, to keep detection within sections active on long trains.  It does no good to free up the section under the train, otherwise bad things happen...

 

Also remember to set however you use your detection to provide a 2-3 second delay on clear, I find it really helps with keeping constant detection values.   I'm still using RR&Co 5.0c.5 because I refuse to spend more money on something "new" that doesn't appear to be much better to me...

 

James

Agreed, detection of the whole length of the train can be pretty crucial, detecting the loco and last vehicle only is a recipe for points changing to clear a conflicting route underneath a train.

 

Ideally detection needs to be very fast detect and slow release, that way it will pick up dirty wheels too. My own detection system uses a pulse stretcher circuit to ensure positive detection every time. 

 

Andi

[melmerby]

Agreed, detection of the whole length of the train can be pretty crucial, detecting the loco and last vehicle only is a recipe for points changing to clear a conflicting route underneath a train.

 

 

Andi

Surely if you have specified a train length of say 60" the route will only be cleared when TC thinks the 60" has cleared the section?

As yet none of my wagons and few of my coaches have any sort of detection and usually there is no problem unless the train stalls for any reason before it's normal stopping point and then TC thinks it has completed the move with vehicles still in the previous section.

 

Keith