I know that this is a hack which allows a LED to run in half wave rectification and light up a standard wall switch. There is a small amount of voltage and current always running in the circuit unless the load is burned out.
Check with local regulations before using this switch. Since this is not CE certified it may present a safety concern. I have had no problems but I assume responsibility in my own home. Play safe and have fun.
You can choose to light one side of the paddle or both.
Step 1: You will need
6.2 KOhm Resistor 3Watt
A diode 1N4007 works nicely.
A couple of LEDs. Unfortunately I used Blue.
Step 2: Disassemble and prepare the switch
The white paddle is in two parts and when warm can be pried apart easily.
Inside of the switch body are 3 parts. There are two stationary sections and a third movable section. Make note of how the parts work and disassemble.
You will need to solder a short wire to each of the stationary sections.
Step 3: Wire the rectifier
The circuit is consists of a diode, LEDs and a Resistor all wired in series. (If you use more than one LED they are all wired in parallel to the series circuit)
The Resistor is soldered to the black lead and heat shrinked to prevent shorts. The diode is soldered to the red lead with the band pointing away from the red wire and heat shrinked. The second lead of the diode is soldered to another section of wire and heat shrinked.
In this case the red wire goes to the LED lead that is rounded and the black wire goes to the flat lead.
The wiring is tucked out of the way and hot glued into place. The switch is reassembled and tested for proper operation before power is applied.
You can add as many LED as will fit into the tight space. Adding additional LEDs will make the lighting effect more uniform. I chose to use 2 per side.
I tried to make this circuit as safe as possible but it still may violate local electrical laws.
assemble the circuit as shown and reassemble the switch.
Step 4: Test and power
While connected you will find that the load, for example, a light will not light until the switch is thrown. There is a small amount of current but it is just enough to run the LED and it is Half Wave Rectified.
If the load is open like a burned out bulb then the switch remains dark. When the circuit is activated the switch will go dark. When switch is in the off position it will illuminate but the load will remain off.
The only indications that there have been modifications will be the 2 visible wires by looking at the back side of the switch... Oh and the illumination when connected.