PCB Present Ornament

For the 2021 Holiday Season, I had a last-minute idea: design a PCB Ornament.

I grabbed a vector image of a gift box. Using Inkscape, I converted it into a KiCad footprint and then turned its shape into an edge-cut layer. Using the silk screen, solder mask, and exposed copper sections, the is very decorative.

On the front are 48 LEDs connected in a matrix. On the back is an AVR 8-bit microcontroller (Atmega8 family) that controls the matrix. The code just scans through turning on the LEDs.

With a 250 mAh LiPo battery, the ornament stays lit for at least 4 hours. There is no charging circuit, so the battery needs an external charge.

For the best visual effect, I used OSH Park's After Dark service. Additionally, all of the traces for the LED.

Build Notes

First, the JST connector is backward from Adafruit batteries. So if you want to use an Adafruit battery pack, you need to either bodge the board or swap the cables on the battery pack. See above image for polarity.

Second, for the ICSP, the pads are "surface mount." I found I could attach a through-hole connector, program it, and then desolder it. If you want to power the present directly, the Vdd pin is shown there.

Third, the "low battery" signal doesn't work. So you can leave that LED/resistor off the board.