Thursday, October 30, 2014

Some great deity once said “Let there be light!”.

I think some great deity once said “Let there be light!”. Well, not trying to be big shots, the N scalers have none the less created light for our N scale Exhibition Layout. We have finally completed our little project that began a handful of months back with a heads together of the bunch to see what we could do.

So our list of materials used was: 
  • 7 lengths of Aluminium tubing of approx. 13mm diameter.
  • 7 curved Ninety Degree Angles.
  • 7 green Plastic Tubes. These were a type of conduit used by the Termite blokes.
  • 7 Galvanized Pipe Strap/Clamps (for the green tubes).
  • 7 x 38mm Drywall Screws.
  • 14 x 20mm Truss Head Screws to hold the strap/clamps.
  • 7 x 85mm Screw/Bolts with Nuts.
  • 6 x Fluoro Metal Reflectors.
  • 3 x 5m rolls 5630 based LED Lighting Strips (300 SMD per meter).
  • 3 x 12 V 6A Power Packs to drive the LEDs.
  • 3 pair Connecting Plugs for LED power from Power Packs.
  • 3 pair Connecting Plugs for LED power between the Pelmets.
  • 7 Plastic Round Chair Leg Caps.

 That’s enough bits and pieces, let’s put it together. Well, the pelmets we got from a friendly sparky in the club – Darryl. He got these from a job he was on that had some left over. These don’t have ends, but are night and white and shiny and very light weight.

Above is a photo showing the end of a pelmet and the two strings of LEDs.

To these pelmets, we used the double sided tape on the LED strips to adhere them to the two channels in the pelmets – this gives us twice the light per metre that a single strip does (OK, I stated the bleeding obvious). We made the length of each LED strip that of the pelmet, less about 30-40mm at each end. This allowed us to add in some plugs to connect the pelmets together in pairs. Because of the power requirement, we needed 3 power bricks and hence three circuits. So we decided to wire the lights up in pairs of pelmets. To connect each pair together electrically, we used simple plugs we got from Jaycar that can only be plugged in one way – keep it simple is out motto – hence we can’t muck it up, now can we…

You will note that the pelmets have a small hole at the end of them. This is what we use to join them together. We have 85mm screws poking out of the aluminium tubes and the pelmets fit over the screw. It leaves about 20-25mm of screw sticking out the top and we’ve found the weight of the pelmets and the snug fit of them over the screw, means we do not need and nuts to hold them together. The pelmet drops over the screw and that’s it – see the next photo:

In the next photo you can see the screw/bolt coming up through the tube and pointing upwards with the pelmet sitting down on it. You can also see the connector plugs that go from the LED strips to the extension leads we made that are zip tied to the ally tubing to pass power up to the lights from the floor. This way the three power blocks sit on the floor and don’t dangle in the air – less chance of problems this way.

By the way, the power packs are just like those we used to have (and some still do) on their laptop computers. Simple, easy to source and therefore easy to replace if need be.

Okay, so that’s the electrical side. The aluminium tubing as mentioned earlier is about 13mm diameter. When we bought it, we also purchase matching curved 90 degree bends for them. The bends are about 50mm radius and the fellow at the metal shop we bought them from kindly installed the bends for us with a gadget he called a “Pipe Bender”. Must be a fantastic piece of equipment to be able to install bends into tubes.

We had ordered the pipes longer than required so we could play around and then cut back the pipe to the length we wanted later on. After playing around we decided on have the LED’s just past the half way mark from the back to the front of the baseboard. So if the baseboards are 600mm, then the centre line of the lighting is at about 350-360mm from the skyboard. Height wise, we left as supplied to us – which is about 600mm above track level.

Now it just happened that we had been given a few years back, some green conduit from our friendly Termite man in the club – Ian. This piping is plastic and is the perfect size for a reasonably snug fit for the aluminium tubing.

The above photo shows the green tube screwed to the back of the layout. A single long screw has been used to go through the bottom of the green tube and into the layout frame, thereby stopping the aluminium tube from dropping through. The clamp is then used to give the real strength.

Because there are no tight fixtures in this design, we now find that it is nicely flexible and if the flooring is undulating, the lighting fully adjusts to this without us worrying about it. Cartage is simple – just some sheets of very thin bubble foam in between the pelmets to stop scratches and the tubes are metal and therefore tough. The power bricks go in with all the other power bits for the layout during transport. Putting the lighting up can be done by a single bloke, but two is faster. Up and running the lights in about 5-10 minutes.

Above we see B1 admiring some of his work at the back of the layout. Now the last thing is length. The layout is 7.8m long and the pelmets cover 6.8m of it. We find the last half metre at each end light up quite well enough with the power we are putting out – a total of about 210 watts of LED’s in total actually.

Now for some empirical data. I got a hold of a light metre and did a few measurements. The ambient room lighting at track level was about 170 lux. At track level, whether measures at front or back or middle, we were getting somewhere in the vicinity of 650-800 lux. Now from the great world wide web and our friends at Wikipedia, we see that some example lighting levels are:

Surfaces illuminated by:
0.0001 lux
Moonless, overcast night sky (starlight)
0.002 lux
Moonless clear night sky with airglow
0.27–1.0 lux
Full moon on a clear night
3.4 lux
Dark limit of civil twilight under a clear sky
50 lux
Family living room lights (Australia, 1998)
80 lux
Office building hallway/toilet lighting
100 lux
Very dark overcast day
320–500 lux
Office lighting
400 lux
Sunrise or sunset on a clear day.
1000 lux
Overcast day; typical TV studio lighting
10000–25000 lux
Full daylight (not direct sun)
32000–100000 lux
Direct sunlight

So I think our lighting setup should show the layout quite well at all venues we attend.

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