Back in 2007 I unveiled the light at the end of the tunnel in my old layout. Since I was about to complete the mountain on the new layout, I installed the light in the new location.
I can see that I need to do some more black painting inside this mountain!
The light at the end of the tunnel is switched off at layout night time.
Here is the original posting showing how the light was made:
I scanned a Faller tunnel portal to get the exact shape of a tunnel entrance. I then copied a small section of a backdrop and cut it out in the shape of a tunnel mouth but scaled down to about half size, printed that out onto paper and cut it out.
Next I took some Plexiglass® (or Perspex® as it is known in some countries) and cut a hole somewhat larger than the backdrop. I drilled holes on the outer edge large enough for 3mm LEDs to be inserted. I painted all the surfaces except the inner curve with silver paint in order to maximize the light that would be emitted from the inner curved area.
I left the half drill holes in the curved part to increase light output along that surface.
I then placed the light frame in a black cardboard box along with the backdrop cutout
and taped it closed with black tape...
The unit is then simply placed in the tunnel. I power mine with a stationary decoder so that I can switch it off at night.