The Yellow Submarine

** July 2019 UPDATE ** 
You can now buy all the parts needed for this project here!

Time to look at a fantastic LEGO Ideas product - the Beatles tribute set 21306 'Yellow Submarine'.

This project was a custom commission for a Beatles fan who loves the model and wanted to bring it to life with lights.

The Model
Set 21306 - The Yellow Submarine

Initial Plans

Looking at the model there's a few obvious options here.

  • Portholes - there's 8 windows on each side with a flat red 1x1 cap on each. We'll only be focusing on the side of the model that faces us - it's a display piece and designed to sit side-on like this.

  • Interior - the ship has interior space for four passengers.

  • Weird Tubey Things - there's four periscope type tubes on top which could be lit up.

  • Front/Rear lights - no place for them yet but these would be logical places to add lights

  • Background lighting. It's a submarine - we could light up the are under / behind it with blue lights perhaps.

Looking inside

There's tons of room inside this model. Clearly it's designed to be able to fit the four Beatles in there, but since they come with a nice display stand most folk would have them outside anyway.

To the rear there's a curious cavity - around 4x4 on top it has a space about 2x4 by 2 bricks high. Easy to access with the curved top connected with just two studs.
Lighting the Portholes

Our first thought here was to put something flashy inside to have the light come out all the portholes at once.

Sounds great but sadly only the upper four portholes are open on the inside. The lower four have tiles connected on the inside surface which covers them.

I first tried with a Multi-colour Light Strip. These are great little boards which cycle through a full range of colours. As a quick test I stuck one to the roof of the cabin right behind the portholes.

This is how that light strip looks when in place:
A multi-colour light strip in use

Here you can see how much light bleed there was through the yellow plastic when in the Red part of the colour cycle:

And here's how it looked running for 30 seconds:

Result : Not ideal. It's too slow, and only the red light really comes through. Not helped by the Trans Red caps on those holes of course. Additionally there's real light seepage through the model.

So time for Plan B which is a no-brainer - those portholes are begging to have bit lights fitted so I stuck eight flashing white bit lights (15cm wire version) in to see how it looks.

First we take apart that cabin roof piece - it's easy to get the porthole bricks out.

Then we just fit the bit lights through. As usual we run the power connector in from the front leaving the bit light trapped on the front as it won't fit through the hole.

We can't use the flat round 1x1 Trans Red Tiles provided so have to swap these for 1x1 round plates instead. They have a bit more space inside for this kind of use.

I repeated this for the lower four portholes using the same technique.

Finally all eight were wired up to a 12 port expansion board and a battery pack (not shown for clarity)

Here's the result:

I'm happy with that!

Flashing bit lights don't give you as much control as when you use an effects board, but they are random and all slightly out of sync. Watching it for a few seconds you can see this and it's mesmerising.

Lighting the Periscope Tubes

I thought this would be a great effect - flashing or static would be great.

And pipes - what's better for running cables than pipes?

Sadly it was not to be. I could add the lights but the cables would be very visible and not what we need here.

Here's how it looks when you start to dismantle it.
As you can see the blue Technic pins hold it together and leave no room for cables. I also found those 90 degree bend pipes are solid in the middle so they're right out.

Onto the next piece instead!

Lighting the Underneath

This one should be nice and easy - to get an ambient glow I just need to mount a strip light underneath or behind the ship and hide the cables.

The two 2x2 trans clear support posts aren't quite far enough apart to fit a light strip so I moved those to 6 studs apart. This doesn't affect the ascetic as far as I'm concerned.
Dismantling the end to fit the cable proved quite straightforward. Remove the upper section to reveal that odd hollow compartment, remove the red arch too, and there's two 2x2 L-shaped plates. Those come off and then you can get to the 2x6 curved piece and that nice quarter-round piece underneath. It's easier done than described!
Once done you can see a clear path to get the cable to the inside chamber.

You'll need to carefully hold the cables clear of the studs when re-attaching the hull pieces:

But the end result is pretty neat now - the cable is barely visible and hidden to the rear anyway.

With all that done - here's how it looks:
As you can see the blue glow looks great and lights up the base and the surrounding area.

Tidying the cables

As with any project like this the devil is in the detail - and normally that detail is hiding the cables!

As we looked at right at the start, there's a curious empty space at the rear of the ship and it's easily accessible. A quick test shows this is the perfect size for one of our Micro Battery Packs. These tiny wonders have a 6 port expansion board built in and have an off-off switch too.

Sadly 6 ports is no-where near enough for us with 8 bit lights and a strip light to power! So we need a 12 port expansion board inside too. By braiding the cables together we can actually make this quite neat.

Here's the final circuit layout we settled on:

And here's how the cables were tidied away. First we fitted the battery pack with one cable to the strip light underneath, and the other to the 12 port board.
The we re-fitted the red and white pieces to trap the cables and braided the bit light wires together into two bundles.
Finally the top goes on and the battery pack is positioned with the on/off switch facing upwards for easy access.

End Result

And here we are - and we think it looks pretty good!

Our client is very happy with this result and we hope you get some inspiration from this project.

Here's the final video in all its glory.

Parts Used

For this project we used the following parts

  • 8 x Flashing White Bit Lights 15cm (2 x packs)

  • 1 x Blue Strip Light

  • 1 x 12 Port Expansion Board

  • 1 x Micro Battery Pack

  • 2 x 15cm Extension Cables

  • 8 x Trans Red 1x1 Rounded Plate LEGO bricks

Because some of these come in packs of 4, this leaves us with the following left-overs for another project:

  • 3 x Blue Strip Lights

  • 2 x 15cm Extension Cables

The cost of these parts is currently around £49 but obviously there's a few left over parts there. If you're interested in recreating this and would like us to put together a custom bundle of parts just drop us a line any time.

Questions / Comments?

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