One of the design directions of this project was to embody a "maker aesthetic". One way we did that is by dual-purposing the product's PCB as the faceplate of the calendar. If you look closely you can see the embossed texture of copper signals just beneath the surface of the calendar. The PCB occupies almost the entire X/Y dimensions of the product, so it's the largest that most people have probably seen.  Fun fact, the calendar's PCB size actually maxes out the capabilities of most standard fabrication services.

To help minimize the number of materials and components used, we leverage the translucent property of fiberglass (FR4) circuit boards as backlighting for each button. The front faceplate PCB allows yellow light to pass through each button from an LED that's mounted on the PCB directly behind.  A standard PCB soldermask is used as an optical mask to only allow light to be seen within each gold button.  The soldermask comes at no extra expense as it's already required for the circuitry that co-inhabits the PCB.  For this product it made sense to use low-cost low-risk standard fabrication techniques, while still affording a  customized look and feel.

A fun aspect of this product is that it's intentionally hackable!  The circuit and firmware are documented online and the main microcontroller is an Arduino, an approachable crowd favorite of hobbyists .  That means tweaking behavior, adding custom feature, and extending the hardware are all possibilities for the customer.

Cost was another important constraint. Buttons and LEDs can get expensive. So when you have 365 of each of those you really need to make clever cost-cutting design decisions.  We opted for touch buttons because they're for the most part free, other than a few modestly-priced chips that drive all the buttons.