Mechanical expanding cardboard lamp - This way up!

Step 10 Circuits and electricity

You can mount a switch on the lamp itself, and a nice neon switch (I think) looks almost indescribably fly, but it's actually far more practical for a floor-standing light like this to have a foot-switch in the power line. For this, you don't even need to worry about feeding the mains cable into the lamp yet. I'll cover this later.

A word about electricity:
Usual caveats apply. It can be pretty dangerous. Working with low-voltage lighting creates a sense of security that sometimes leads to complacency, and I electrocuted my fingers a few times working on low voltage lighting projects. I figured that it was all low voltage, so whats to be afraid of? Forgetting that the open contacts on the mains-side of the power switch were still cooking at 240v. It hurt and made me jump and made me spill my tea, fortunately not into the live electricals.

Be very wary of anything that you have plugged into the wall, and think carefully before plunging your hand into places where it might inadvertently touch wires or connectors. Think once, think twice. Think don't drive your car on the pavement.

The plan:
Acquaint yourself with the wiring illustration. There are four entirely separate circuits in total, one for each bulb. The positive lines are individually switched on or off by the position of the lowest struts against the uprights.

I went for four completely separate circuits here for two reasons: One is that the wire I was using was quite thin (1mm square) and I didn't want it being overloaded (bigger is better when it comes to wire gauge) by running two lamps off a common negative line. The other reason is that unlike my previous transformers, this one had four individual sets of output terminals. Other transformers have tended to have a bank of three positive and three negative terminals, so I had to common them somehow, and having two lamps running off a shared negative made sense. Doesn't make a fabulous amount of difference which way you go, as long as the positive lines are switched, but do be careful not to place too much load on thin wires.

The switching is implemented very simply, by having a bare wire embedded into the lower struts that comes into contact with a bare, live wire at a certain point in it's travel.

The first task is to install these switching wires into the uprights and into the lowest short struts. Onward!