Most of us have a powerful computer within reach at all times, which makes calendars and clocks largely obsolete. At this point, they’re basically just stylistic choices that add a bit of decor to your wall. But, so is a painted portrait of you holding your cat, and everyone obviously still buys those. So, who are we to judge? If you’re nostalgic for calendars and clocks and want to scratch that itch affordably, MelnEdgars’ tutorial has you covered.
This is a cool PCB-based digital calendar and binary clock that you can build yourself for about $5. MelnEdgars designed it in Autodesk EAGLE for the Instructables PCB Contest, and you can take advantage of the design to gain some geek street cred. The year, month, date, and day of the week are all displayed on tiny little 0603 SMD LEDs, but the year only goes up to 2023 (shown as 2021 in photos, but fixed now). The time is displayed on another set of LEDs in binary format.
If you want to create this, you’ll first need to order some PCBs — MelnEdgars recommends JLCpcb or Elecrow. You’ll also need the LEDs, resistors, MOSFETs, and an ATmega328P — the same microcontroller used in an Arduino Uno. Once everything arrives, use an Arduino to flash the code to the ATmega328P. Then, just assemble the board. It’ll be a little tricky since the LEDs and resistors are so small, but should be manageable if you have some decent soldering skills. The result is a neat little calendar/clock that would look great on your desk.