Nathan True constructed a neat color shifting orb project. He was inspired by a Ask Slashdot question and looked at the Ambient Orb for design ideas. His initial idea of using a Parallax Basic Stamp was discarded since color mixing needed a faster processor. The solution was to go with a Microchip PIC16F84A, the 16F84 still has a large following since there are vast resources available on the internet for programming it. Many hobbyists today are shifting toward the cheaper and more powerful 16F628 and 16F88 microcontrollers. Read Byron Jeff’s article about why the 16F84 is obsolete. Nathan has developed an interesting method for the PIC to “set and forget” the color settings of the LEDs, there are some 555 timers and 7491 shift registers that handle that. If tackling complex color mixing wasn’t enough Nathan also added wireless communication so that the system could be controlled by a remote computer system! Total cost for his project came out to about $44. Want to build your own? Take a look at the schematics.