A snowflake shaped Xmas ornament with blinking LEDs.
This uses an ATTiny85 to drive 6 blue LEDs which are multiplexed. There's a button on the front which is used to toggle display modes and sleep.
When sleeping, the ornament uses about 200 microamps of current, little enough to run off of a coin cell battery for about 1000 hours (in reality, probably less. I don't know, I didn't measure it)! While running, it uses about 2 milliamps, which could last for about 120 hours.
The part was designed using KiCad. The shape of the PCB was generated with svg2mod. The outline of the board was modified from Wikipedia (Public Domain), I added a hexagon in the center to make room for the button, ATTiny85, and battery.
I use damellis/attiny for ATTiny85 support in the Arduino editor (via the VSCode extension).
| Reference | Item |
|---|---|
| U1 | Attiny85V |
| R1, R2, R3, R4 | 50 ohm 1206 resistor |
| R5 | 10k 1206 resistor |
| C1 | 1 uf 1206 capacitor |
| D1 - D6 | 0603 LED |
| SW1 | 6x6mm SMD Pushbutton |
| BT1 | CR2023 Battery Holder |
Yes, the traces aren't parallel to the edges of the board, and yes it bugs me too.
