LEDs are super bright, efficient, low-power light sources. They are available in many colors, such as white, red, green, and yellow.

You can obtain LEDs at several places online, including www.superbrightleds.com. However, your local radio shack, or electronics supply will have them as well. When comparing LEDs, take note of the brightness level, measured in "mcd". Radio Shack has LEDs as bright as 1100mcd, but elsewhere you can find up to 10000mcd.

Right next to the LEDs at RadioShack, you will find the holders for them. This is a small piece of chrome that has a reflector and a threaded washer on it. The reflector will help with aiming the light, and the threaded portion may be useful come mounting time. Plus they look cool. Below is a White LED, and then a White LED in its holder.

With the LEDs, we are drawing about 20ma of current. This is great, because it will allow the use of extremely thin (and lightweight) wire. You could even use magnet wire, which is incredibly fine, but that might prove to be too delicate to work with. I chose 30awg wire.

LEDs come as a raw component. Imagine that, you are expected to create a functional circuit on your own! This just means that you'll need to install a resistor in order to limit the blistering power of your 6-cell pack. Of course, RadioShack has plenty of these guys. Running without a resistor will let you have extremely bright LEDs for about 30 seconds. After that, they will incinerate. We will cover exactly which resistors you will need below.

Its beyond the scope of this article to cover soldering in depth. I will say this to those of you with some experience. Soldering these little components is not like doing motor leads and battery bars. Its more delicate. You will want to use a heat-sink or hemostat to isolate the components from the heat, especially if you are going to insist on using that 45watt iron you already own. Also, a pencil tip will make things a lot easier than a big chisel tip.

Here is my favorite Soldering How-To it is specifically for doing a battery pack, but it covers all the basic stuff.

You'll need to attach the lights, and wires, and jacks and things to the lid, as well as the vehicle. I prefer to use Shoo Goo, or similar stuff, as it is flexible, and nonpermanent. You can find this stuff at your LHS or Target. Silicone Sealant will do as well, but it is more permanent.

Decide what power source you plan to use. Using a 9V battery can make for simpler wiring, but now you have another battery to deal with. The 9V can be expected to last around 10 hours.

If you would prefer to use the 6-cell pack as your power source, I use a value of 7.5 volts for the calculations for extra safety.

There are two values associated with each LED, and you will need to know these. The first is the "Forward Voltage" of the LED, the second is the "Rated Current."

Please refer to the example variables for the calculations below.

Step 1 - Determine the Remaining Voltage Across the Resistor

This is simple. Subtract the Forward Voltage of the LED from the voltage of your Power Supply. What you are left with is the voltage that the resistor will "See". We are left with 3.9 volts.

Step 2 - Determine the Required Resistance

Again simple. Divide the remaining voltage by the rated current. Don't forget to convert milliamps to amps by dividing by 1000. Using the calculation to the right, we find that the Required Resistance is 195 Ohms

Conclusion

We've taken our two knowns, voltage and current, and used them to solve for resistance. In this case we would need a resistor of at least 195 Ohms. As stated above, 330 Ohms is a relatively easy to find component. An expert informed me that the brightness of the LED will not be affected by a slightly higher resistance in the circuit.

Want to skip the resistor altogether?

If you are going to run off of a 6 celled pack (7.2v) you have a pretty convenient voltage here. Two 3.6v LEDs wired in series will perfectly match the 7.2v power source and no resistor would be required!

Examples

Now that we've selected our components, lets make the circuit.

If you have enough wire, just cut two strands that are about two feet long each. You will have some slop to work with that way.

Strip 1" off of the end of each wire.

Using a pair of "ExtraHands" can be very helpful with this part. Or even an alligator clip on a stick will help.

In my picture, you see two resistors, but that is because I used two 100 Ohms to create a 200 Ohm resistor. You can combine them in this way if you need to, but the 330 Ohm will work great all by itself.

Using your soldering iron, and a very small amount of solder, connect the resistor directly to one lead of the LED. You can use either lead. I have isolated the components from the heated area by using an alligator clip, and a red heat sink (available at RadioShack.) Anything similar will do, you just want something there to "take the heat" instead of the component.

Take one of the stripped wire ends and wrap it around the "free" end of the resistor. Connect with solder.

Take the other wire and connect it to the free lead on the LED.

Congratulations, one of your LEDs is now complete.

Strip the other ends of the wire, and connect the circuit to your power supply (probably your 6-cell battery). Just stuff them in there for now, don't solder anything. If it doesn't come on right away, just reverse the wires. Voila - let there be light!

Repeat these steps for your other LED(s).

If you want to be really lazy, you could just jam the wires onto your connector when you want LED light. I wouldn't do this because a wire may come loose and short the battery. I wonder what that would smell like?

Method 1 - 9 Volt Battery

You'll need to find yourself a 9V connector like the one pictured here. If there is a connector on the other end, just snip it off. Twist your new wires onto the connector wires, connect it to your 9V and test your lights. If everything lights up, you've got the polarity correct. If not, just reverse the wires.

If your lights are coming on, take the connector off of the battery and use a little solder to make your "twisted connections" permanent.

You can use Shoo Goo and just glue the 9V right to the lid. When it dies, it can be removed with a little force.

Method 2 - Quick Disconnect

Here is the "trick" way to set this up. Use a 3/32 headphone jack to power your LEDs. Now you'll just have a little plug that dangles from your lid, instead of a big ole 9v.

Start with the female jack that you install somewhere on the chassis. I found it convenient to place it next to the receiver. Don't worry about which one of the leads on the female is positive or negative. Just take a two lengths of your wire and connect the leads directly to your ESC.

Here is a picture showing how to connect it to your ESC. That is the plug that connects to your 6-cell pack.

Go ahead and solder it up. You can use your Shoo Goo to install it permanently.

Once your jack is wired, take the wires going to your new lights and just wrap-connect them to the male plugs positive and negative leads (one each). Plug it in and see if it lights up. If they don't reverse your wrapped wires.

Take your other LED(s) and run their wires to the plug as well, and make sure they all light up.

Now is the time to trim the LED wires to their desired length. Make sure you leave enough slack to slide the lid off over your antennae tube. Trim the wires, and restrip them. You may want to go ahead and install the lights now, to make sure you've got the right length.

Solder all the wires to the appropriate connections.

Finishing up is mainly a matter of gluing your wires to the lid, installing the lights where you want them and letting everything dry before any bashing about.

When installing the lights, use dremel tool to remove material slowly so you dont make too big of a hole for your LED holder. Keep making the hole bigger until you can get the holder in there. If your holder has a threaded washer on it, you may be able to use this to mount the holder. Otherwise, copious amounts of Shoo Goo will fit the task! You can also glue the resistor to the lid to bulletproof the LED/Resistor connection.

Something else you may want to do is provide some reinforcement. If you pull your lid off, and forget to disconnect the plug, you don't want that force pulling on your glued wires, or worse, the resistor or LED.

Take a body washer, and dremel or cut the hole out so it is big enough for your male plug to go through.

Run it through the washer two or three times in loops. Pull everything tight, and now you can Shoo Goo the washer to your lid. (Pictures to be provided)

Now if the plug gets yanked, at least it won't pull on the LED or resistors.

You can reinforce the plug by filling it with sealant of Shoo Goo. Or if you are really trick, you'll purchase a small rubber plug at a hardware store and shave it down until it fits in the back of your plug.