Fitting light(s) to brake van for current detection

[ITG]

I’m at the early stages of exploring/implementing automation, using iTrain on a test layout. I’d like to include a tail end vehicle (ie a brake van) which has a current draw, to enable detection by sensors. The obvious thing seems to be to add lighting to a brake van, be that a tail light and/or interior lighting. So a few questions…

1. where would I find metal wheels, presumably on a split insulated axle?

2. and these would then need pick-ups which I’d need to find?

3. if I use LEDs, what resistors would be needed (I’m using DCC)?

 

This will be the first time I’ve tried to do anything like this, so any tips most welcome.

Ian

[Steven B]

1. What scale? Any metal tyred wheelset can work if they're isolated from each other.

 

2. There are a number of commercial kits that involve things like springs coiled around the axle or contacts that rub on the wheels. I've used phosphor bronze wire for pickups.

 

3. If using LED then you'll need a 1000 to 2000 ohm (1k-2k) resistor depending on the LED and how bright you want it. Start at 1.5k and work from there.

 

3b You'll also need a standard diode connected anode to cathode across the LED to prevent it being damaged by the switches in polarity of a DCC signal (or feed via a diode bridge)

 

Steven B

Edited August 19, 2022 by Steven B

[ITG]

4 minutes ago, Steven B said:

1. What scale? Any metal tyred wheelset can work if they're isolated from each other.

 

2. There are a number of commercial kits that involve things like springs coiled around the axle or contacts that rub on the wheels. I've used phosphor bronze wire for pickups.

 

3. If using LED then you'll need a 1000 to 2000 ohm (1k-2k) resistor depending on the LED and how bright you want it. Start at 1.5k and work from there.

 

3b You'll also need a standard diode connected anode to cathode across the LED to prevent it being damaged by the switches in polarity of a DCC signal (or feed via a diode bridge)

 

Steven B

Thanks for the response. It’s 00 gauge. 

[DCB]

I have a lit brake van, in 00, it has a Hornby dublo metal chassis with metal rim wrenn wheels with wiper contacts rubbing pressing down lightly on the tyres, 4 wheel pickup.  It has a red LED tail light diode controlled and an LED interior light with a rectifier so it stays on in both directions.  I think the main resistor is 1k, ith a subsidiary for the red which runs brighter than the yellow interior.  It only runs on 12 to 16 volt controllers, I would use 1.5 K with Duettes and the like which poke out 20 plus volts.   It has a electrolytic capacitor to keep the lights from flickering too much and after 20 years I can't remember how I made the tail light go out in reverse, but it still has a run every now and again and the tread wipers keep the wheels commendably clean. Unlike most vehicles the drag from the pickups is beneficial in keeping couplings taut.  I have a pair of brake composites with lights, pick up with Lima wheels through pin point bearings, 2 wheels per bogies, rectifiers, ceramic caps, one LED per compartment, and an Autocoach, Bachmann split axle wheels with wipers on the exposed sub axles, again one bogie pick up, capacitor, rectifier several LEDs etc .  They all look good in darkness, One LED per compartment makes all the difference especially if some ae dimmer than others, the bigger the ceramic cap the better they work, but the wipers on treads is by far the best system for keeping wheel treads and contacts clean

[DCCconcepts]

We make wheels with pickups, as well as wheels with integral resistors.

https://www.dccconcepts.com/?s=wheelsets+quality

 

And also pickups to add to your existing stock.

https://www.dccconcepts.com/product/pickup-wiper-12-pack/

 

Best Regards,

The DCCconcepts Team

[ITG]

9 minutes ago, DCCconcepts said:

We make wheels with pickups, as well as wheels with integral resistors.

https://www.dccconcepts.com/?s=wheelsets+quality

 

And also pickups to add to your existing stock.

https://www.dccconcepts.com/product/pickup-wiper-12-pack/

 

Best Regards,

The DCCconcepts Team

Thanks. I hadn’t thought about resistive wheels. I’m not that bothered about lighting, but didn’t know there was a simpler alternative. I’ll need to measure the existing wheels.

Ian

[WIMorrison]

Which type of feedback units are you using as that affects the value of the SMD resistor that you need to stick to the axle., as does your track voltage.

 

The required current to ‘trip’ the detector ranges from 1mA all the way to around 20mA and as you can see one value will not suit all scenarios.

[ITG]

14 minutes ago, WIMorrison said:

Which type of feedback units are you using as that affects the value of the SMD resistor that you need to stick to the axle., as does your track voltage.

 

The required current to ‘trip’ the detector ranges from 1mA all the way to around 20mA and as you can see one value will not suit all scenarios.

Hi Iain,

I’m using DR4088LN, with a Z21 on standard settings. Any suggestion re the required trip value, and therefore if the suggested DCC Concepts resistive wheels will be ok?

thanks

[WIMorrison]

I don't know what value the resistors are that they use but a DR4088LN will trip on 1mA, though I would normally head for a little higher. The default Z21 output is 18v giving a required resistance of around 9k. 

 

Assuming that your existing wheels are metal with an insulating bush I would make my own resistive axles. it is very easy.

 

Start with some 1206 SMD Resistors and get some conductive electric paint (you can get cheaper, but this is what I use. You then stick a resistor onto the axle at the insulated end with some superglue and when dry paint some of the conducting paint onto the resistor pads and the axle on one side and the back of the wheel on the other. Then give them about 2 hours to dry by which time the axle will be conducting.

 

The cost per axle is pennies and whilst the first is awkward by the time you have done several it is a 5-minute job that you do by turning the wagon upside done and doing it all in situ - easy-peasy 😇

 

 

[DCB]

On 21/08/2022 at 20:57, DCCconcepts said:

We make wheels with pickups, as well as wheels with integral resistors.

https://www.dccconcepts.com/?s=wheelsets+quality

 

And also pickups to add to your existing stock.

https://www.dccconcepts.com/product/pickup-wiper-12-pack/

 

Best Regards,

The DCCconcepts Team

Pick ups look very useful even to DC types like me.    Pics of the wheels would be useful.   "Better than RP25?"    Do they work on set track?   I'm a bit sceptical, well a lot actually, after having to re profile Dapol wheels which I think are RP25, to stop my Mogul constantly derailing on code 100

Incidentally that grainy grey background to the web pages makes your website text really awkward to read. Like one of those old grainy photocopies we use to get.  Really irritating to those of us with ageing eyes..   

[WIMorrison]

Be aware that the axle spring pickups require that you pull off one wheel to fit the spring, and then refit the wheel.