|Four LED Flashlight|
What if you want something brighter than 2 LEDs? Well, you can add two more LEDs by basically duplicating the two LED circuit and putting it in parallel. The LED specification calls for 3.6 volts and .02 amps. The circuit uses two 90-ohm resistors that are in series with the LEDs.
You can buy small electronic project boxes 2.4"x1.8"x0.9" to house the whole thing. These boxes can be purchased through electronic stores or over the Internet. But you might try some sources closer to home - like a craft store or the checkout counter at the local grocery. Many of the items placed where you wait in the checkout line are in nice small packages that might be adapted.
Understand that the more LEDs you use, the faster they will use up your battery. However, they will still last a lot longer that a conventional light bulb.
There is a great web site called OtherPower.com that has a good explanation of using multiple LEDs.
Ready for more fun with LEDs? Try these out: