I have tried several techniques for
lighting buildings on my model railroad. I shall outline my preferred
technique.
Incandescent
Incandescent lighting creates a warm light
which replicates lighting typically found in residential buildings and in office
buildings from the first half of the last century. I no longer use incandescent
lighting for two reasons:
- the bulbs will eventually burn themselves out – I have no desire to have to dismantle a nice model building to have to change a bulb, and
- depending on the bulb and its current draw, incandescent bulbs can get quite hot and can be a fire hazard.
Light Emitting Diode (LED)
I find LED lighting superior to
incandescent lighting in many respects:
- LEDs are available in many colours, including what is usually described as “warm white” which creates light very much like incandescent;
- LEDs run cool, reducing the fire hazard;
- An LED mounted in a model building will likely outlive its owner, avoiding the need to install a replacement; and,
- LEDs come in a huge variety of colours, intensities, shapes and sizes.
I like to create a ceiling for each model
building room which will be lit. If the LEDs I am using are surface mounted,
then the LEDs can be glued directly to the underside of the ceiling. If the
LEDs are the dome style with the anode and cathode ‘legs’ protruding from
behind I make a 90 degree bend in the legs, feeding them through two small
holes in the corners of the ceiling before gluing the LEDs with hot glue so they are shining
into the centre of the ceiling and not downwards toward the floor.
I then glue ¼ inch wide strips of white styrene around the perimeter of the ceiling creating a shallow "light box". This allows the light from the LEDs to reflect off the ceiling and side strips for a diffused lighting effect in the building interior. I paint the exterior of the light box ceiling black to absorb any stray light that finds its way through the styrene. Light shining out through the walls of a building is not a prototypical effect, to say the least.
As for how many LEDs to install in a particular building, this is a matter of trial an error. Variables which affect the lighting intensity include:
I then glue ¼ inch wide strips of white styrene around the perimeter of the ceiling creating a shallow "light box". This allows the light from the LEDs to reflect off the ceiling and side strips for a diffused lighting effect in the building interior. I paint the exterior of the light box ceiling black to absorb any stray light that finds its way through the styrene. Light shining out through the walls of a building is not a prototypical effect, to say the least.
As for how many LEDs to install in a particular building, this is a matter of trial an error. Variables which affect the lighting intensity include:
- The size of the rooms.
- The type of wall coverings in the rooms - are they light and reflective or dark and light-absorbing?
- The level of ambient light in the space where the model railroad is set up.
- If your model railroad will always be operated with the same ambient light in the room you may want to have brighter lighting than if you will be dimming the room lighting to simulate dusk or night time.
- Your personal preference.
I wire the LED conductors to each other, cathode
to cathode and anode to anode (i.e., in parallel) and then solder leads which
will run to a DC power source to light the building.
If the voltage from your power source is higher than what the LED is rated for it is mandatory to insert a current-limiting resistor in one of the leads attached to the power source. Failing to include a resistor guarantees that your LED will destroyed. Many LEDs are rated for 1.5 volts or 3.0 volts but higher voltages are available. Some micro or nano surface-mounted LEDs come with a tiny resistor already wired to them - make sure you know whether this is the case before you do your wiring. I use a 12-volt regulated power supply to power all accessories on my home model railroad, including for building lighting, so I must include a resistor in my lighting circuits.
There is a formula using Ohm’s Law to calculate the rating of resistor to use. Over the years I have gravitated to using a 560-ohm 1/8 watt resistor in all LED applications. I purchased 1,000 of these from Digikey a few years ago, making them individually very inexpensive.
Unlike incandescent bulbs, LEDs will only work if they are hooked up to the power source using the correct polarity. If they are hooked up backwards nothing will happen - the LED won't light up but it won't burn out either. LEDs have positive (anode) side and a negative (cathode) side. Dome-style LEDs have two metal "legs", with the shorter of the two being the cathode (negative) and the longer being the anode (positive). In addition, the bottom edge of the LED body will have a small flat spot on the cathode (negative) side.
Once the resistor has been soldered into the circuit on either the anode or cathode side the power source can be hooked up. If you can't be bothered remembering which is the anode and which is the cathode trial and error works fine - if the LED doesn't light simply reverse the wires (again, make sure you have a resistor in the circuit before you hook up anything to the power source).
If the voltage from your power source is higher than what the LED is rated for it is mandatory to insert a current-limiting resistor in one of the leads attached to the power source. Failing to include a resistor guarantees that your LED will destroyed. Many LEDs are rated for 1.5 volts or 3.0 volts but higher voltages are available. Some micro or nano surface-mounted LEDs come with a tiny resistor already wired to them - make sure you know whether this is the case before you do your wiring. I use a 12-volt regulated power supply to power all accessories on my home model railroad, including for building lighting, so I must include a resistor in my lighting circuits.
There is a formula using Ohm’s Law to calculate the rating of resistor to use. Over the years I have gravitated to using a 560-ohm 1/8 watt resistor in all LED applications. I purchased 1,000 of these from Digikey a few years ago, making them individually very inexpensive.
Unlike incandescent bulbs, LEDs will only work if they are hooked up to the power source using the correct polarity. If they are hooked up backwards nothing will happen - the LED won't light up but it won't burn out either. LEDs have positive (anode) side and a negative (cathode) side. Dome-style LEDs have two metal "legs", with the shorter of the two being the cathode (negative) and the longer being the anode (positive). In addition, the bottom edge of the LED body will have a small flat spot on the cathode (negative) side.
Once the resistor has been soldered into the circuit on either the anode or cathode side the power source can be hooked up. If you can't be bothered remembering which is the anode and which is the cathode trial and error works fine - if the LED doesn't light simply reverse the wires (again, make sure you have a resistor in the circuit before you hook up anything to the power source).
The following pictures show a recently completed Walthers building kit project:
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| Walthers Golden Valley Depot kit |
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| Building completed including interiors but before lighting and roof |
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| LEDs mounted in the corners of the styrene ceiling panels - note that the LEDs are pointing into the box created by the perimeter styrene strips, avoiding pools of light on the floor of the building |
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| The LEDs lighted |
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| The ceiling lighting panels resting inside the building with wiring. The 560 ohm resistors cannot be seen as they are encased in the "liquid electrical tape" that I like to use to coat bare wires in situations like this. |
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| Completed station showing interior lighting at dusk |
I like to have a certain amount of animation in a model railroad because it is more prototypical and makes a scene more interesting for the viewer. Animation can also apply to building lighting. For example, in homes, warehouses and office buildings all interior lighting is rarely turned on or off all at once. In a home lights will normally be turned on in the kitchen and possibly living room or great room at mealtimes. In the evening the kitchen light might be turned off. As evening progresses some or all bedroom lights may be turned on while the kitchen light is turned off. Similarly, in a commercial building different areas may be lit at different times of the day.
In a later article I shall explain how I animate my interior lighting using excellent little electronic devices made by Arduino.