Diy: Light To Led, Switch Specific

[j diggi]

First off please move this to the right forum, I don't have permission to post in DIY. Second, this is my first offical DIY write up, so bear with me.

I'm sorry for the quality of the pictures. I had trouble finding drivers that would work with it, plus its not the best camera for close ups. If you have any questions/ideas/comments feel free to e-mail or PM me I'll be happy to help.

"LEDs (Light Emitting Diodes) are those little colored lights you see in electronic equipment, household appliances, toys, on signs, and many other places. Red, yellow and green ones are the most common, since they have been around the longest. Other colors, like turquoise, blue, pure-green and white are much newer, so you may not see many of them around yet. But you will.
LEDs are different from ordinary light bulbs because they do not have a filament to break or burn out. They generate very little heat, and are ideal for putting lights into battery-operated equipment like telephones, toys, and portable computers.

An LED is basically a really fancy diode. Diodes only let current (electricity) to flow in one direction and not the other. LEDs are diodes too, but they have the unique "side effect" of producing light while electricity is flowing through them.

In the simplest terms, an LED is made with two different kinds of semiconductor material: one type that has too many free electrons roaming around inside, and another that doesn't have enough. When an electron from one material (the donor) gets pushed across a thin barrier and gets into tiny spaces in the other (the holes), a photon or particle of light is produced.
The color of light depends on a number of factors, including the type of material they make the LED with and the material's quantum bandgap (how much energy each electron needs to pack in order to cross the barrier).
A smaller bandgap that fairly weak electrons can cross gives you infrared or red light, while a large bandgap that needs really strong electrons gives you light that has a blue or violet color to it.

Things that go on inside of an LED are a little more complicated than this, but you get the idea." (from http://www.ledmuseum.org/)

Items you will need.

5mm LEDs color of your choice
Resistors (if not using a 12VCD LED, more on this later)
Soldering Iron/gun
Solder
Flat head screw driver (1/4 tip)
Razors
Heat shrink
Wire cutters
Needle Cutters
File or Sandpaper

Note on resistors. The LEDs I used in this project are 2.8 - 4.0 V LEDs (3.5V typ) .030 mA. Your LEDs may be different, but all this info will be listed on the side of the package. To use these LEDs on a 12VDC system you need a resistor to drop the voltage going to the LED.

Ohms = (supply voltage - LED foward voltage)/LED mA
Ohms = (14.6 - 3.5)/.030
Ohms = 11.1/.030
Ohms = 370

Resistors come in many values. If you can't find a value that matches yours use the next highest one. In my project I used 390 Ohm, 1/2 watt resistors. On to the project.


Remove the light bulb holder(s) by turning counter-clockwise. Set aside the switch.



Using a knife/razor or your finger nail unbend both of the leads from the bulb and straighten them out and remove the bulb. Make a mental note of how the leads bend around the tabs.


The LED will no fit in the hole with out removing the lip. I shaved it off with a razor and then filed it down to make sure it fit. The one on the right is the one I modified.


Thread the 2 leads through the 2 holes in the bulb holder.


Take the shorter lead and bend it around the holder tap, just like the orignal bulb was installed. Trim the excess.


Cut the other lead down to about 1/4". Also cut the lead on the resistor.


Solder the resistor and LED togeather.


Slip a piece of heat shrink over the end, making sure you leave about 3/8 - 1/2" of the lead exposed. Using a lighter/heat gun shrink the tube.


Bent the lead to the other tab. You might have to remove some of the plastic on the top of the holder so the lead doesnt slip off. At this point you want to move the leads around as little as possible, they break very easy when moved around alot. I know I broke of 2 leads doing this project.

Install the LED back in the switch using a screwdriver. You may need to use a good amount of pressure to make sure the holder makes it all the way in. The leads on the LED/resistor are a bit thicker than the leads on the bulb are.

Next you have to make sure that the lead with the resistor goes to the positive side. If you put the resistor lead on the ground side it won't work at all. Putting the LED on the wrong sides is the biggest problem I have found, but there is an easy fix to this. While the holder is still in place, make a note of which lead is going to which contact on the switch. To fix, losen the the holder and rotate it 180 degrees.

Finished switch

[cynosurecivic]

im not sure what this DIY is for. changing the bulb inside a switch to an LED? or did i miss something?