In November 1998, SILICON CHIP published a very popular Christmas Star project, based on an Atmel microcontroller.

Recent advances in microcontroller technology mean that this new design, based on a single 8-pin PIC micro, has considerably fewer components and can run from a pair of 1.5V batteries.

As it is also easier to build and you can re-program it if you want different patterns, we believe this new Christmas Star will be even more popular than the original!

It runs through a programmed pattern sequence, held in EEPROM on the PIC. With a suitable PIC programmer, such as Microchip’s low-cost PICkit 2, it is possible to load a new sequence into the EEPROM without affecting the underlying code. There’s no need to understand PIC programming to create your own display sequence!

How it works

Fig. 1 shows the complete circuit, such as it is! It consists of little more than the pre-programmed PIC12F683-I/P microcontroller, 20 LEDs and a few resistors.