General Lighting advice and information, Part 1
LIGHTING WITH DCC
This is a BIG subject as of all the ways you can add life to a model, the adding of realistic lighting is the most striking, bringing locomotives, rolling stock and layout to life.
Lighting starts with a good power supply and for rolling stock that means at the very least clean track and good pickups, so I’ve put in a lot of info on this critical area in parts 3, 4, 5 and 6.
Modellers are pretty innovative people and there are many ways to achieve some things: If YOU have a lighting story or project images that you’d like us to feature, drop us a line and we’ll look at adding them to our website…
To say “thanks for the contribution”, we’ll happily provide the creators of all published images or stories a selection of our “prototype white” LED’s and a TCS “Fleet-lighter” lighting and accessory decoder at no charge!
(1) Models and Lighting:
Light is an important ingredient in the creation of a realistic model, whether it is a diorama or model railway, an item of rolling stock or a vehicle or building that forms part of a larger model.
A little time planning will pay dividends later. Making sure that the concept really does “fit” with the model is important, otherwise you risk gaining the impact of lighting at the cost of performance, fidelity of appearance or serviceability of the model.
We list the lighting types later, however it is first necessary to think about the factors surrounding the choice of light and the subject that you have chosen to illuminate… there are several things to be taken into account when planning the addition of lighting to any model. These are:
(a) How will it be powered?
There are several options here… depending on the type of light chosen and the vehicle or model to be illuminated, the choice will be quite different.
Will you power it directly via a power supply or voltage regulator, via a rechargeable battery, from the light functions of a DCC decoder or directly via a pickup from the rails?
DCCconcepts have developed a fantastic product called “Flicker-free” which will give you 100% steady lighting on AC, DC or DCC layouts, and the power storage is so good that you coach lights will even stay on with the controller off on an AC or DC layout! Click here to see it & learn more.
FLICKERFREE in action - A Hornby Pullman with both added interior lights and original table lamps now totally stable - A nice warm glow rather than hard light ensuring realism is preserved while interior detail is enhanced
(b) How will it be controlled?
Again, there are several choices, and having the best form of control will allow you to bring a model or a whole layout to life. Will it be permanently on, triggered by a detector of some sort, controlled by a DCC decoder or accessory decoder or perhaps even via a secondary circuit controlled by a decoder (such as a relay) or a computer system. Will there be operating conditions that automatically bring a light to life perhaps? (DCCconcepts Flicker-free will work with all methods)
(c) What sort of “Light” will best suit the model?
The things to be considered here are the physical size, ease of installation and wiring, heat generation and dissipation, the potential for long life and later servicing, lighting current draw, voltage available, special effects needed, the “look” required, the colour or tint of the light emitted etc…
(d) How will it “balance” with the rest of the model or diorama?
We don’t want to create a spectacular lighting effect that is dramatically out of character or scale… To retain “believability”, it is important that there is balance in impact between all aspects of any model. i.e.: Will the preferred method work to look like or properly reflect the type of lighting used during the period modelled. Will it harmonise with other illumination on the model, can it be made bright or dim enough.
(e) Can it be installed without compromising the model?
Can the wiring be run without taking away from the look of the model, can it be controlled realistically, can it be made to look like it is part of the design, rather than a later addition. (e.g.: There is nothing less realistic than a passenger coach with a wire dangling in the aisle). Will the illumination create heat, and if it does will the model be able to cope with it?
(2) Types of light source (LED and incandescent):
The choice of lamp or light you install will have as much impact on the final “look” of the model as how you install it. Let’s take a quick look at the available selection of light sources.
(a) Incandescent lamps:
These are the traditional form of hobby lighting, and is a miniature form of the conventional light bulb – in other words, it consists of a tiny glass bulb with a metal element which glows when voltage is applied. The positive side of this type of lamp or bulb is that it is generally very easy to dim to a low level, plus it has a very wide light pattern (it glows in all directions).
Incandescent lamps are therefore good for use in things like buildings where a wide-ranging soft light is needed; however, the conventional “bulb” does have some significant drawbacks when it comes to use in rolling stock, signals and locomotives. For example, one needs to be very careful when using incandescent bulbs in plastic loco bodies as they can get hot enough to melt plastic if used at higher voltages.
DCCconcepts “truly scale” station lamps (They are due late 2009) use an carefully chosen incandescent bulb and even incorporate individual level controls so you can adjust them to the perfect level for your layout.
CLICK HERE to see them and learn more.
Soft illumination with a generally “warm” look good for buildings and creating a “wash” of light around buildings. Wide illumination pattern, easily dimmed by varying voltage. Bulb life will usually be very long when powered at lower than the recommended design voltage. Super-Micro sized 1.5v bulbs may be appropriate for some older steam locomotive prototypes, where large low power headlights are required (i.e. Narrow gauge or pre-1920 locomotives). However, resistor values are critical for these tiny lamps and use of voltage regulators or diode bridge low voltage supplies is recommended.
Incandescent bulbs will have a short life if used at above rated voltage. Significant heat generation (They get VERY HOT when used at higher voltages – just like a normal bulb). May be variable in quality and performance batch-to-batch. Limited availability in smaller (grain of wheat or smaller) sizes.
Unless you have proper specifications or the ability to accurately assess voltage and current requirements properly we strongly recommend that you restrict use of incandescent lamps to building or accessory lighting effects only. If you wish to use them in loco’s, ALWAYS use the correct value series resistor in line with the bulb. This is particularly important on DCC as the voltage will ALWAYS be at high levels.
We strongly recommend use of the DCCconcepts “Lighting Tester” to assess both the required resistance and the bulb performance prior to installation within any rolling stock.
(b) LED’s (Light Emitting Diodes):
LED is an Abbreviation for Light Emitting Diode. An LED is in fact a semiconductor device that emits visible light when conducting current. Because of its reliability, low cost and low current draw, The LED has replaced incandescent lamps as indicators in almost all electronic equipment.
The LED has also the current favourite among modellers for the same reasons. LED’s are available in an extremely wide range of shapes, colours and sizes, LED’s are also widely distributed, with common sizes available from most local electronics parts stores and broad distribution of specialized sizes and colours from specialists who understand the special needs of modellers like DCCconcepts.
There is a really useful set of LED sizes available to meet every need – from the standard 3 and 5mm LED that is the most common shape, a 2mm parallel pin type, a 1.8mm almost the perfect shape for a loco lamp and even a tiny 0.8mm LED that is so small that TWO of them will fit on the end of a matchstick!
CLICK HERE to see a range of really useful types of LED for every need!
LED's are readily available in a very wide variety of shapes and sizes, from large and “super bright” to LED’s so small that two of them will fit on the end of a matchstick. LED’s come in a large colour range including Red, green, yellow, orange, white, blue, Infra-red and of course the modellers favourite “Prototype” or “Golden” white, which enables model lighting to look just like the gas, oil or incandescent lighting used in rolling stock and locomotives from the early steam era until the 1980’s.
LED’s are incredibly reliable. They are also able to be adjusted in output level from very bright to “dim” by varying voltage or in the case of constant voltage systems such as DCC, by varying the resistance used with the LED. LED’s also have one more VERY helpful characteristic when used in modelling… they will only turn on when the polarity of the power source is correctly oriented for the LED. In other words, they form an automatic “self reversing” system of lighting on DC powered systems.
LED’s require a “Minimum” voltage to turn on. With red, green and yellow LED’s, this is usually approximately 1.7V although this is not always the case and it is wise to check (White and its variants are normally in the 2 volt range, however they MAY need about 3 volts - check the Manufacturers spec if you need more info about a special LED) LED’s must always be “current limited” or they will fail immediately.
Current limiting is an easy task, and needs only the simple addition of a series resistor into the led circuit. Apart from these two items, there are almost no drawbacks with LED’s.
Note: We will repeat this info elsewhere, but a few notes here may de-mystify use of LED’s a little. The dropping resistor value is simple to calculate. It is the net of supply voltage minus the 1.7V led voltage (use 3v for white LED’s) then divided by the led brightness current expressed as "amps" (ohms law). As a “rule of thumb” you will always be safe on Model railway voltages if you use approximately 600 ohms for red/green/yellow and 1000 ohms for white and its variants.
If you would like to calculate values exactly, this simple diagramme will help in working out more precise values.
Note the orientation of both cathode and anode with respect to the ground end and the supply end. Usually with an LED the longer lead is the anode (+ lead).
(3) Extending lighting / function ability of your decoders:
Sometimes you need “just one more function” or “just a little more power handling” to get the result you need… and sometimes it would be nice to be able to use a limited function decoder in a loco rather than go out and buy a more expensive one. Don’t worry: There are a couple of easy ways to do this, and fortunately, they are NOT expensive. It can be easy or as complex as you’d like it to be too, so don’t be put off by worrying that you may not be able to cope with it!
(a) Adding a single lighting or operational function the simple way:
A simple and effective way to do this is to add a relay. Relays are available in super small sizes, so this can even be done in N scale! Basically all you need to do is:
* Obtain a small DPDT or SPDT Relay: This is a relay that will connect one set of contacts when active, another when inactive. An example of this from a local parts reseller is shown here – the relay in the picture is only 20x10x10mm.
However it’s a BIG one – we have them much smaller…. Click here to see them!
* Connect the “common” contacts directly to track power (red and black decoder wires)
* For “On/Off” use, connect the accessory (say a smoke unit) via the terminals “normally off” when the relay is not powered. For “either-or” use, Connect one thing you want to power directly to one set of output terminals, the other to the second set of output terminals.
* Connect the decoder function to the relay coils (activation) terminals. Now, when you activate the function, the “outputs” will change – 2 functions for the price of ONE!
(b) Using transistors to create a second function “option”: If you are comfortable with using transistors and electronic components then you can do the same sort of thing without a relay or any other external device.
Take a good look at this circuit from the “Circuits and diagrammes” section of our website:
Don't be put off by the quantity of parts shown: this is actually a very simple and clever circuit originally created by Bob Backway…
However we have re-drawn it to make it easier to follow and we've colour coded everything. We also show a "Vero-board" layout to make it easy to make.
A simple description….
In the top LH corner, it adds a transistor to function as a switch to turn a cab interior light OFF as a Headlight is turned ON. This neat solution will work reliably at LED current draw levels, is incredibly low cost, easy to do and VERY compact, so it will even fit in N scale without too much difficulty. Even if you know nothing about electronics, you CAN make this kind of circuit – just use the transistor type and resistor values shown.
(4) Getting power: Controlled power for your lighting
After selection of the light source, the way you obtain power and then transmit or connect it to the light source will have the greatest effect on the quality of light that results. That is not to say the powering of lights is a complex subject – it is not, however because light sources may vary in “look” depending on voltage, current, type of power (AC or DC) and will vary in quality depending on HOW the light is taken from the source and connected to the lamp, its worth thinking about before you start. Let’s look at this from the different perspectives of “source” and “connection”.
Power Sources: These can be roughly broken down to three categories:
Mains or external power. This covers all forms of power source from specific power supplies for lighting use, power taken from “accessory” or spare terminals on model power supply transformers and “wall Warts” or small low current transformers usually associated with the charging of mobile phones or power supply to otherwise portable products such as laptops etc.
Safety is critical when using ANY mains based product. If you are making your own power supply be very careful when creating it, always install any live high voltage wiring in a fully insulated case, take great care in the wiring of any mains plugs (it DOES matter which side of the plug the brown or red “phase” wire is on!) and add at the very least a 1 amp fuse at the mains side of the supply. If at all unsure please ask a professional to help.
Once the supply is decided or constructed, we must consider the output voltage and current carrying capacity of the supply. In general we can use AC at any appropriate low voltage (say from 3 to 15 volts) for incandescent lamps, but will always need a DC supply for LED’s. This DC supply should preferably be regulated as this will ensure a stable voltage level for any LED based layout lighting.
We recommend between 12 and 15 volts AC or between 9 and 15 volts DC as ideal “standard” voltage levels for layout lighting, and have based any recommendations in this section on these levels.
There are few problems with using external power for layout related lighting, with only basic issues of safety, correct voltage and adequate current delivery to be considered.
If you are unsure of the suitability of any power supply, check with an expert or if you like, contact me on email@example.com and I will assist as much as possible.
Battery or “stored” power: This will generally be restricted to “onboard” power supplies that are either independent from or “re-charged” by layout track power. Widely favoured in outdoor or larger scale use because they fit well with radio control or track independent power needs, in general these work extremely well but they are much harder to arrange, and do have some downsides.
Positives: Very consistent light with zero “flickering” due to track pickup problems. Stable supply voltage for LED supply. Usually independent of consistently available track power.
Require external or automated switching for on/off, require space to store batteries, need voltage and charge regulation circuits. Complex to install.
Track power is the third method. Of course this is what all our loco’s do in the most common scales – take power from the track, so it will always be one of the most commonly used methods. Because there is a significant difference in the way DC and DCC layouts apply power to the rails, we will look at these as separate sub sections. Conventional DC Layouts: In its most basic form the use of normal DC track power for lighting is exactly the same as pickup for locomotives. Simple wipers on either wheel or axles of the stock that the lighting is installed in, however we do need to think about this a little as when trains stop so does the power… and while running, DC track voltage varies depending on the needs of any locomotive in the “active” block.
The simplest method to get the best from track power is to use DCCconcepts “Flicker-free” which will provide stable power, voltage regulation and a huge storage so lights stay on even with power off.
Click Here to learn more about DCCconcepts Flicker-free
For the DIY amongst us, here is a simple, basic diode based trick.
Providing the diode spec is reasonably fast, it will work on both DC and DCC – simply make up two strings of either two or three diodes in series and place them in opposing directions between the pickups and one motor lead (IN4001 is a very common low cost diode and ideal for this use) .
Each diode represents approximately ¾ of a volt, so this TWO diode setup will give you an approximately 1.5 volt power supply for low voltage bulbs or LED’s. The downside of this is that it will also drop the voltage to the motor by approximately same amount– not usually a problem as we never run at “full” anyway. See the diagramme directly below.
While LED will need more diodes in each string, as they require higher voltage, so this method may not be practical for other than coloured LEDs.
Alternately, There IS another option if you are a little more confident with electronics, as per the diagramme above…
You can make an excellent and very stable 5 volt power for very low cost using a simple circuit which employs a 7805 voltage regulator. This circuit will give you a fixed 5 volt output to use for low current incandescent lamps or to power several LED’s without compromising motor voltage.
This circuit is usable for both DC and DCC purposes. We recommend that you use a 50volt capacitor and choose the larger capacitor value (220uF) if you have the space for it. It will also be necessary to insulate the heat sink (metal flag) of the voltage regulator from the chassis… but apart from that, there is little to worry about with this circuit which is both easy to use and easy to assemble.
Here we are very well served, as we have the choice of constant direct track power for coach and rolling stock lighting AND the option of “switchable” power via a DCC decoder.
The options are limitless - This departmental brake van has a lamp in the guards hand made from a DCCconcepts 0.8mm SMT LED, with power supplied via silver loaded conductive paint so no wires are visible, plus a working red oil type tail– lamp make from our 1.8mm Microdot LEDs, which are almost the perfect size for HO or 4mm scale lamps as they come! (model by Martin McCormick)
However, the available power is not limitless, so for a mid to larger layout, or a layout with lots of illumination on rolling stock, we still need to plan for power requirements…. For example, if you use incandescent bulbs, a full train of coaches can consume a lot of power if you don’t think it through carefully!
Because there is opportunity for a LOT of lighting with DCC, we strongly suggest that you standardize on LED’s for as many purposes as possible. Careful planning and correct selection of LED’s will allow you to use no more than 2~5 milliamps per LED, which will let you run all of a loco’s lighting requirements for no more than a very tiny 6 to 15 milliamps, and at the extreme you could even equip a passenger coach with lighting in EVERY individual compartment for less than say 100mA – Very acceptable at 1/10 amp for a long lighted passenger train.
With the DCCconcepts Flicker-free this load will be at its lowest, as both charge rate and discharge rate are tightly controlled to give you the best lighting with a low layout loading. As it also includes all other parts needed, including all LEDs and circuit boards to mount them to, its economical too!
Collecting power from the track (as per Ten steps to better performance)
Without excellent pickup our loco’s don’t run well, and any operating functions, sound systems or lighting that we choose to add to loco, coach, caboose, brake van or any other rolling stock will perform intermittently or perhaps not at all.
At their best, well tuned pickups will result in faultless running. At worst, the constant “power-is-on, power-is-off” action of intermittent or inadequate pickups can, in addition to reducing the quality of performance and increasing frustration, can actually damage things like expensive decoders!
We have no hesitation in saying that ENSURING HIGH QUALITY POWER DELIVERY TO WHERE ITS NEEDED is the single most important key to success in model railway operation and is totally essential if smooth performance is wanted.
Of course there is more than ONE aspect to good electrical pickup: Before we even get to the part where power goes from the wheels to the loco or lights, we need to be sure that the source of the power is good… so just a few words here about that.
• Taking power from the system around the layout: This is NO different whether it’s a DC or DCC layout. Stay away from light gauge wire for all power feeds. Use heavy wire for all main track “bus” or feeds – and try to standardize on something solid enough to carry a reasonable current. We suggest even for a modest layout, no wire that carries power for more than 3 feet/one metre should be less than 16 gauge, and if the layout is mid sized or larger, 14 gauge would be great!
• Taking power from the main feed wires to the rails: We can be a little lighter here, but DO use lots of “droppers” from rail to the main feed wires. One of the BEST phrases to keep in mind here is “every bit of track should be soldered to something”. We suggest that every yard/metre of track should have “droppers” from rail to the main feed wires for best results.
• Droppers can be small if they are short: for droppers where it’s hard to get to, or in difficult places, use droppers as small as 22 gauge if they are short (150mm/6” or less). Standardise on 20 gauge for droppers in easier to get places. These can be as long as 16” / 400mm without much voltage drop. It’s OK to use solid wire if stranded is hard to use well… dropper wires have NO movement and its better to make a neat joint after all!
• Keeping things Clean: The rail tops should shine like the prototype and so should the tread of the wheels (wheel backs should be really clean too where there are pickups!) But… you can’t spend your whole modelling time just cleaning stuff, so establish a good routine for cleaning everything.
Here’s my own “plan” that I use to keep things up and running on my own model railway… it really DOES work!
There are four parts… wheels, pickups, track and the track-bed area. I try to keep to this simple set of guidelines. The first part of a track cleaning regime is clean wheels, as dirty ones will gum track and other things up again in no time at all.
• Use only steel or nickel silver tyred wheels on everything.
Where an option exists, choose steel. Do not run ANY stock with plastic or brass wheels on the layout at any time.
• Inspect all new stock and wheels.
Clean even if new to remove any metal-turning or electroplating residues before putting anything on the track.
• Inspect all wheel-sets and be sure the back-to-back is correct.
Even new stock is, more often than not, incorrectly adjusted.
The back to back is critical for good reliable running on rolling tock AND locomotives. Be rigorous here, and include visitors stock as well. Good “Back-to-back” gauges are hard to find, and old ones are no longer correct as wheel profiles are now finer than when the NMRA gauge etc were created, so DCCconcepts have created a range of several sizes and types to fit every need. Click Here to learn more about them.
• During the year, re-check stock when it’s added or taken off the track.
Check for BOTH wheel back to back and cleanliness Reject any stock with wheels out of BTB or with obvious muck on wheels and do not run until cleaned.
• Mark the calendar and clean wheels on all stock annually.
The second part is improving pickups: They must work well on every wheel
• If you notice flickering lights in lit stock or occasional stalling or stuttering in any loco movement check immediately.
Take it off the track immediately and set it upside down on the bench (a “cradle” of foam rubber is good for this) and ONE wheel at a time, check that the pickups are doing what they should. I use either a meter set to ohms, a continuity tester OR a couple of wires from a power pack to test this.
EVERY pickup should work reliably every time it’s tried. If it doesn’t work first time, adjust it, clean it or tweak it until it does.
I don’t want to get into a battle over what sort of chemicals to use, but DO NOT spray aerosol products like CRC or WD40 around – they will eventually do more harm than good.
Use a cotton bud and a contact cleaner to get the oxidization off pickups, axles or wheels, and add any contact enhancer or similar item with the tip of a toothpick, a syringe or a clean cotton bud. We ONLY want this stuff where it’s needed, not all over the mechanism and body work.
Top quality contact enhancers are hard to find. DCCconcepts stock and use one of the best available. To see it, learn more or to purchase, Click here please.
If the pickups of the loco or stock are less than perfect, then add pickups using phosphor bronze wire or strip soldered to a PCB material.
You’ll be surprised just how much better things will work if you do this.
Why – because a rigid chassis or truck/bogie will only ever have all 4 wheels on the track on a totally perfect bit of track. If the track is even a couple of thousandths of an inch out of level, or the chassis/bogie/truck is not perfectly square, the best you will ever have is 75% wheel contact, so if you also have any isolated points or dirt anywhere the loco will probably stall! The best solution here is to add suspension to the stock, but that’s a big job. For now, we’ll settle for just adding as many pickups as we can.
Tip: buy yourself a pair of thin solid GOLD ear rings (Plain pierced ear “keepers”).
Cut a tiny bit approximately 2mm long and solder it to the end of the pickup wire. This will give the best possible pickup reliability as gold does not corrode!
Cost is lower than you think and they will provide enough material for many pickups. Gold is easy to solder by the way.
The Third part of all this is to remove any build-up of gunk from the rails:
• Do it as soon as you see it – gunk encourages more gunk – and it’s usually there for a reason – something is not clean enough!
Again, the purpose of this is NOT to debate what to use – just clean it.
We do however recommend that you try to get an abrasive block from an electronics supply house (they are sold to clean Circuit boards) rather than use a “track rubber”. We find that model railway track rubbers shed lots of bits everywhere and do as much harm as good. DCCconcepts sell an exceptionally good track cleaner of the correct type - to see it and learn more, Click Here.
Alternately, a top quality “rail cleaning wagon” will help, but ONLY if you buy the best—most are simply not worth the cost, and simply look bad and add significant drag to the train! DCCconcepts stock the highly regarded “CMX Clean Machine”.
Click Here to learn more about it.
• After cleaning off all the “Macro gunk”, wipe the rails over with a lint-free cloth lightly moistened in your cleaner of choice.
We like a strong solvent cleaner such as acrylic thinners used carefully (cloth only damp with it, not wet) as it whips off the track in no time at all. You can also use Isopropyl or any one of the many alcohol based cleaners – it’s up to you.
• When track is clean, we lightly treat it with a contact enhancer.
Again, we council against WD40 and CRC, preferring one from an electronics supply house. We apply this in two ways – where we can get at it by wiping it on… where we cannot, by adding a few drops to the rail and sending a loco over the area to be protected several times.
The fourth part is critical if you want the benefits to last…
VACUUM the track area thoroughly! This is ignored or missed by most people, but vacuuming up the dust and track cleaning residue does more to stop build-up of future gunk than any other step.
Do it just once and you’ll be a true believer!
• However... we don’t like using the standard vacuum cleaner nozzle on the trackwork – it’s a bit too big and aggressive for use on a model.
If you cannot find a set of fine hoses and adapters (Often sold for cleaning sewing machines and computers), we recommend the following:
Make an adapter “plug” that will block off the end of the standard vacuum cleaner hose. Obtain about 6 feet/2m of some flexible plastic pipe of about 1cm/1/2” inside dimension, and drill through the “plug” so it is a good push fit into the hole. If this is too hard, just use “duct tape” (also known as Gaffer tape) to temporarily connect the new smaller hose to the vacuum cleaner nozzle.
Next, so you can control the power of the vacuum, make a hole approximately ¼ to 3/8” (6 to 8mm) about 4”/100mm from the other end of the pipe. This is so by placing your finger over the hole as needed you can vary the suction level to suit the area you are vacuuming.
(By the way: we recommended the extra length so you could pass it over your shoulder to keep it out of the way / keep the weight of the vacuum hose off the scenery).
• Now, clean the track-bed:
Turn on the vacuum and pass the tip of the hose along the railhead – actually touching it if possible. If you change the bag before doing this, you will see easily just how much it will suck up – In fact it will inevitably be an amazing amount and variety of fine dust and dirt…. All of which was just sitting there ready to be attracted upwards by airflow and static charges as the loco or train passed. All of this gunk would have eventually collected on track, wheels or in mechanisms and bearings!
This presentation continues on the next page - General lighting Info #2. If you would like to go there directly, please on the link below.
Do you still have questions? No problem – just click here to email us and ask, we’ll be happy to help!
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