Rob ‘linear’ Arnold has put together a fantastic LED Series/Parallel Wizard.  Not only will it calculate the current limiting resistor you need, it will draw a circuit diagram, and give you full statistics on power usage.  If you are just getting started with Electronics, this is a great resource for learning about LEDs.  Experienced users will enjoy a quick check of their math.

The array above is designed for some Blue LEDs I have laying around.  I wanted them to run with 15mA which is well below their max, but still very bright.  In this case 1/4W resistors should be fine and each should be 120 ohms.  I should be safe hooking this array up to an Arduino since each LED will draw less than each I/O pin can handle AND total current draw is only 60mA.

Very Cool Stuff!

http://led.linear1.org/led.wiz

The PCB for my very first Arduino shield arrived today from BatchPCB. At first glance everything looks good. The silkscreen with my name and web address didn’t come out so well but that was probably my fault on trying to fit in too much.

Looking forward to assembling then with some Blue LEDs!

This pattern is called Row Your Boat. As one of the strips starts to get brighter, a nearby strip will join in the fading.  After completing a fade cycle, they start switching colors. There is a random strobe thrown in there as well.  The first 10 seconds are with a diffuser (piece of paper), the last 10 seconds are without.  The final panel will use a diffuser.

Initially I tried to get a LCD screen working with my Illuminato based Arduino. After a couple of attempts I realized two things: 1. The Iluminato is not ready for prime time. and 2. I burned out the LCD.  So I decided to move on to the LCD strips I have from Sparkfun.