My Sunjar - An esp8266-Powered Light Alarm Clock

This is my Sunjar (code). Inspired by those (expensive) light alarm clocks, my Sunjar gently wakes me up in the morning to this (click to see a youtube version):

Sunjar ocean pattern

And then fall asleep to flames: Sunjar fire pattern


This is my alarm clock, so I can put in the features that I want:

  • NTP-synced time. Never forget about DST again. Always accurate.
  • Wakeup by ocean light, with a 1-hour brightness ramp-up.
  • Capacitive touch-sensitive override - snooze if I want to, just touch the jar
  • 1-hour red-light sleep timer for going to bed
  • Cool patterns during the day
  • Over the air (OTA) firmware updates


  • An esp8266 (Wemos W1 Clone)
  • 5 WS2812 LEDs
  • 1 50M ohm resistor

Wakeup / Sleep Time Algorithm

I decided I only needed two different wakeup times, one for weekedays, one for weekends.

If you would like to see a fancier light alarm clock with a web interface to set custom alarms, check out this soothing alarm clock.

Capacitive Touch Sensor

The Sunjar is just a heavily frosted mason jar and it has a stainless steal rim. By connecting this rim to particular pins on the microcontroller, I can use the rim as a capacitive touch sensor, detecting when humans touch the jar.

The electrical schematic for this is extremely simple, requiring only two pins and a resistor:

Sunjar Schematic

My code easy to write thanks to a library that handles the hard parts.

This touch sensor serves to override the lamp, for when I want to sleep early, use it as a night light, or need to snooze in the morning.

A Love Letter to “Pacifica”, the ocean pattern

“Pacifica” is the name of the ocean pattern. It powers the wakeup mode (with the ocean-inspired palette) as well as the sleep mode (with a fire-inspired palette):

Written by Mark Kriegsman for the art piece “Beneath These Waves Lies Light”, it still looks beautiful on 5 leds:

Its beauty comes from its complexity and depth. There are four simultaneous “waves” intersecting each other with extra effects for darker hues and whitecaps.

Future Improvements

  • I think eventually I will want an easier way to change the alarm times
  • Maybe I can make the touch sensor detect long holds or double taps for more interesting commands
  • Synchronized color schemes for special events copied from a different project
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