This repository contains source code and CAD files to build and program a wordclock.

The wordclock is designed inside an IKEA frame (SANNAHED, 25x25 cm). Behind the front glass panel, a black mask allows light through transparent letters which are individually backlighted with colour LEDs.

The clock displayed in the picture above spells out the time in French (il est midi moins cinq: it is five to noon), but design can easily be adapted to other languages. In addition to time of the day, extra text for special days (i.e. birthdays) is highlighted in other colours. Letters can be used as pixels to display other forms of text. The picture below displays today's date (Lun 18 04: Monday Lundi the 18th of April).

Lights are controlled via custom printed circuit boards, multichannel LED driver integrated circuits, and an Arduino Nano Every board breaking out a AVR XMEGA 4809 microcontroller. Timekeeping is performed with an accurate Real Time Clock (RTC, DS3231M). The clock is powered via 5V/4A on a barrel jack, and the RTC is internaly powered from a coin cell to ensure timekeeping even when the clock is unplugged.

The source code attempts to follow SOLID principles. It should be easy to update by anyone willing to add features, modify the word layout, alter colours, add animations, and so on. As examples, the git repository includes extra behaviours for the clock:

• it can display time with numbers, using letters as pixels (source),
• similarly, it can display the date (source),
• on startup, it shows a splash screen with a welcome message (source),
• to debug electrical connecticity and software mappings, LEDs can be controlled to blink one at a time (source),

All behaviours can be loaded on the clock, one can then use physical buttons at the back of the frame to switch between behaviours. These buttons also permit to adjust the time and date.

Unless otherwise mentioned, the source code is licensed by Rémi Berthoz under the MIT License. Exceptions are:

• The OneButton library (in src/Protocols/OneButtons) used to control the hardware push-buttons, which is licensed by Matthias Hertel under a BSD style license (http://www.mathertel.de/License.aspx).

• The USB USART library (in src/Protocols/USB_USART), adapted from ArduinoCore-megaavr, which is licensed by Arduino SA. under the terms of the GNU Lesser General Public License.

• The src/millis.cpp file, adapted from ArduinoCore-megaavr, which is licensed by Arduino SA. under the terms of the GNU Lesser General Public License.