After scouring the dangerous prototypes google code repository this past spring, I stumbled upon a novel design for a hackable holiday ornament, with glowing SMD LEDs as lights strung on a tree. Clever use of exposed vias and silkscreen printing created a festive effect of glittering decorations and an ATtiny13A wrapped up as a gift underneath the tree. At that moment I decided I needed to build on this design and hopefully have something nice to give as a gift this season.
The original design had only one NPN transistor switching 10 0805 chip LEDs. My original plan was to replace the transistor with a 74HC595 shift register, but the tiny13’s 1K of flash space proved too small for my mediocre coding ability. Thus, I simplified to 5 discrete transistors switching the 10 LEDs in groups of 2. I modified Ian’s original design to drive a PWM on 5 pins using an interrupt on the tiny13’s timer.
Presently working to adapt the board layout. Adding the extra passives and NPNs has made for a busy front, so I’ve moved them (mostly) to the back. Working against the clock the design done in time to have my boards from DirtyPCBs before Christmas, so there are no URLs or references in this post. They’ll be added later.