This is the fireware used in my entry for Hackaday 2024 Business Card Challenge Contest.
- Business with contact information and QRCode for website
- Credit card size of 85.5x54mm
- 3.2mm thickness including 1mm PCB
- It is a clock/watch with 12 Charlieplexing LEDs
- It is also a ATtiny3227 development board with all the pins (22-GPIO pins) break-out.
- Programmable with megaTinyCore as an Arduino or with bare metal with just VSCode and avrdude.
- Powered by a CR2016 coin cell battery (98mAh)
- Designed for low-power, with design target of 1-2uA during sleep, and 2.5mA when time is showed.
- More than 3 years battery life based on viewing the time 24 times a day.
- Less than $8.00 BOM (based on sourcing from DigiKey).
Further description can be found at https://hackaday.io/project/196294-business-card-clock-attiny3227-dev-board.
27 May, 2024 - Original Code for the Challenge entry
31 Jan, 2026 - Add code to use sw2 to enter time adjust mode
Press sw2 would enter the time adjust mode,
- first pressed it shows current hour,
- second pressed shows current minute
- third pressed exits the time adjust mode
Press sw1 within the time adjust mode would advance the hour or minute to the next value