While decorating the tree with lights, I thought it would be nice if the dog had some bling too. I briefly looked for red/green lit dog collars in a Christmas theme, but didn't find anything like I was thinking. There are lit dog collors, but all one solid color.
This is a pretty basic LED flashing/PWM project. It was put together over a few hours total. I typically use PIC microcontrollers, but this time tried out the Atmel AVR (an attiny13a in this case). Though not needed by this project, I wanted to try out the gcc c compiler, for which there is none when it comes to PIC. Overall was pretty impressed, it was integrated nicely in the Atmel GUI development/debug tools.
The fade in and out on the two channels isn't completely smooth. Given the simplicity of the code, it is probably related to the different forward voltages on the leds, and how close two in series are to the battery voltage. Good enough.
This is probably the last time I make a LED based project without a printed circuit board. I'd rather spend the time building and etching boards than doing such tedious wire wrapping. I opted not to for this project, but I considered using Pyralux flexible PCB. It can be found on ebay in smaller quantities.