Proper Traffic Lights!

This blog marks the launch of our lovely new Traffic Light components!

We've often been asked how to fit lights into traffic lights to use our Traffic Light Effects Boards.  So now we have done the hard work for you by soldering three tiny lights into each of these traffic lights.

There are loads of different ways to build a LEGO traffic light, as proven by the many varieties seen in official LEGO sets such as the modular buildings, Ghostbusters Firehouse HQ and others. And of course there's a huge difference in design between European and American traffic lights. 

So to keep it simple we've replicated the design LEGO released in the Xtras Set 40311. It's our favourite for it's simplicity - it'll look great in any city scene.

Image (c) The LEGO Group


We had to come up with a few tweaks to make this possible.  The LEGO design has a base which is a solid moulded part.  Apparently it's called a "Tile, Modified 2 x 2 with Bar and Stud with Stop Ring".  Well I call it a 2x2 with a pole on top, but either way it has to go!

Instead we have used Grey LEGO hollow pipes and a standard 2x2 jumper plate to create the same effect.

The end result is just over 9cm high and hides three LED bit lights.  The base is glued together for strength, and the three black 1x1 bricks are similarly glued to protect the LEDs and wiring.  The coloured 1x1 round studs can be removed, the top 'hat' piece can be removed, and the whole light unit can be rotated to ensure it faces exactly where needed.

Looks pretty close to the original doesn't it?

Simple Operation

At it's simplest you can wire up one light to a power source and have a fixed setup.  If you don't like flashing lights this option is a good one and will add realism to your city setup.

Alternatively get one of our Traffic Light effects boards and hook that up.

Here's how that looks:

The circuit diagram for this couldn't be easier - just hook up the three lights in the Traffic Light to the Effects Board directly:

Complex Operation

The next level up is using these to light up a more realistic traffic junction.

Here's a T-Junction which is clearly in need of traffic management!
(Apologies to our US and European customers - we drive on the left over here so this diagram is based on that!)

We are going to use a single Traffic Light Effects Board for this. 

Lights A and B should show always the same colours - allowing traffic to flow freely both ways down the main road.

Light C should ONLY be green when both A and B are red, allowing traffic from the side road to drive either way into the main road without hitting anything.

This can be done quite simply - just swap the Red and Green wires over for light C.  Here's how that actually looks in practice.  We're using a 6 port expansion board connected to each output from the Traffic Light Effects Board.

It looks messy but it's pretty straightforward when you try it.

After all that work this is what you get - we're demonstrating with just lights A and C here.  Light B should be exactly the same as Light A of course.

And there you have it!  This is just an introduction - we hope you can see the possibilities and how easy it is to expand the design.  A single Traffic Light Effects board could easily run quite a lot of traffic lights when you can wire them up using expansion boards.

Parts Used

For this project we used the following parts.

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