I wanted some dim LED lights to provide some basic hallway lighting at night..
Building: I wanted it to be super simple, and fig-8 speaker wire was probably going to be the cheapest to use for low voltage lighting. I was thinking maybe 3 core would be good to give me the opportunity to have more than one colour light, like a data channel for colour. Obviously LEDs are polarity dependant so I was wondering about wiring two LEDs in opposite polarity, turns out this is called reverse parallel and it works just fine. So the basic principle is wiring a LED in series with a resistor to a 12v source. Now if I switch around the 12v positive and negative that LED won’t light, but one wired in reverse parallel will.. Hence I can have two colours depending on the polarity of the wiring. That’s where the relay comes in. I have the relay hooked to a light switch which changes the polarity and hence colour. And another switch for the 12v plug pack power source. Then all the LED resistor pairs are wired in parallel along the fig8.
I cleaned up the LED connections with heat shrink cable and attached some flexible wire in the heat shrink cable to allow me to position the LEDs.
The two colours are white and coloured (mostly blue except for my chroma display thing). Also I added a fuse to the power supply.. This is pretty important.