Building a Power Distributor

This project is something I made to help effectively light up small stages. I built it specifically for another purpose (which will be revealed soon), but there is no reason why this couldn't also be used for stop-motion animation - with plastic building blocks!

Most people would be at least passingly familiar with Lego - those little plastic men and women who live in a re-buildable world. Well, there are loads of people who make films with them. A quick search for "Lego movies" or "brickfilms" on YouTube will yield a plethora of results.

Sadly, most of these are very poorly made films. It is quite easy to put a little bit more effort into these films to make them better. Lighting is one of the big problems. This system will allow the film maker to light their sets more effectively.

The Brief

This system is designed to allow several small, low-power lights to be run simultaneously from a single source. The lights need to be both low power for safety (most of the people who make these films are invariably under twenty) and to decrease the amount of heat being generated (plastic melts when it gets hot - go figure... ).

Construction

Initially, I was considering caged power supply (like this) and mounting it in an enclosure. I discarded this idea as it would mean having to play with mains power.

I went for a 12V DC 5 amp pre-built unit (now discontinued) which made it easier to build.

First, I collected up the parts that I needed.

Collecting the tools

This involved mainly some wire, connectors, a case, tools and a few odds and ends. I used two colours of wire to easily identify positive and negative, some matching plugs and sockets and a case to mount it all in.

Basic assembly

Above you can see how the connections will work. I used some fairly common DC power connectors that would allow me to easily find more (of both the plugs and the sockets) if I needed to do upgrades or repairs later on.

First, I soldered on the wire to the back of the sockets. The case I marked up to take eight sockets:

Marked case

This should be more than I would need at any given time that I could foresee at time of building whilst still allowing some expansion. This also allowed me to have a suitable density of sockets on the case, while leaving enough of a gap between them that I could easily unplug any given connection without disturbing the others.

All the sockets wired up

Once all the wires were soldered onto the back of the sockets, I put heatshrink tubing over the soldered joins. That's what the little black things at the bottom of the above picture are.

These make the difference between a shoddy job and a professional-looking job. Better than just wrapping some electrical tape and more secure. As can be seen in the picture below:

Use of heatshrink

The top cable has the heatshrink on it, the bottom one does not. See the difference? I love that stuff. The only thing one needs to do is to plan joints ahead, as you need to remember to slip the tubing over the wire before joining.

The case was drilled:

Drilled case

And the plugs mounted:

Plugs mounted

As you can see, the case was drilled at both ends as well as on the top. One hole was to let the cable in (as seen in the above image) and the other end is for the fuse holder. I'm a big believer in fuses - they stop the house burning down if things short out (a new fuse is a few cents, a new house is a bit more!).

In this case, I matched the fuse to the power supply. Since it was a 5 amp supply, I fitted a 5 amp fuse. This way, if I accidentally plugged in too many lights, hopefully the fuse would blow instead of the power supply.

Partial assembly

Now it starts to become clear how the unit will work. The eight sockets are mounted in the case, ready to accept the plugs from the lights. The black cable on the right goes back to the power supply. The short cable sticking out the left is where the fuse holder will go.

Jumbled wires

The fuse holder is mounted (the silver and black bit on the right hand wall of the enclosure), all the wires are connected together (looks like an 'orrible mess, don't it?) and it's all secured down. At this stage, I used my multimeter to thoroughly test the unit for shorts, incorrect polarity and any other problems that might cause a failure.

Fortunately, I had been thorough and no mistakes were discovered.

(Note: testing needs to be very thorough - if you don't find the mistakes, mother nature will. And she is unforgiving and has a cruel sense of humour.)

The finished unit

The finished unit

Taadaa! The unit is ready to go.

Pictured is the first light that I bought for this poject. This is a CCFL (Cold Cathode Flourescent Light) twin-tube light, commonly used inside computer cases as a case mod. They are cheap, small and consume only a small amount of power.

All I did to this light was change the computer style plug for one of the DC style plugs so that it would connect straight to the unit I had built. I kept the in-line switch so that I could turn it on and off without having to unplug it.

I had been tempted to mount an amp meter in this project so I could see how much power was being used, but I decided against it as it would be an extra complication with little benefit.

Despite the "cold" in the name, be aware that these lights (especially the ends) do get quite warm. Not massively hot (although they sometimes do when they are nearing the end of their life, especially at the ends of the tubes), but hot enough to soften plastic. Make sure that they are mounted in a way that they do not come into direct contact with soft plastic toys (such as Lego bricks).

There are other types of lights that I intend to obtain over the next few weeks. Mainly LED lights and other automotive and camping style lights that have a small footprint and which run off 12V. These should make lighting small projects much easier.

And speaking of lighting, here's the finished product, lit up:

All lit up

I'll post some more pics of the unit in action and maybe get a better shot up once I clean the clutter off my desk. If you decide to build this project (or something similar) make sure that you are confident in your abilities first.

Remember: Electricity + Inexperience = Death & Fire

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