Schedule Clock

I’ve been working on an analog-style LED clock that shows you when you’re busy. It’s capable of displaying the next 12 hours of appointments from your online calendar. Without pulling out your smartphone, you can get a sense for how much free time you have before your next appointment. The clock is made up of 12 lines of addressable LEDs organized as a ring. Each LED represents a 15 minute block.

I built a prototype of the clock using a thin wooden frame, 48 addressable LEDs, a RTC chip from Sparkfun, an Arudino Uno, and an ESP8266. Once a minute, the ESP8266 connects to WiFi and requests the schedule from a PHP script I wrote. This script fetches multiple calendars from both Google Calendar and iCloud, merging and filtering out all of the unneeded data. The ESP8266 streams the data to the Arduino Uno, which parses and updates the display. The first prototype is functional as of January 2022, and I’ve been testing it to find bugs and gauge reliability of the schedule feature.