displayed on the same group of LEDs, there is often
(once per hour) a conflict on which color to use. In
these cases, the LED in conflict will blink back and forth
between the hour and minute color.
For example, if the time is 10: 50, the 10th LED from
the bottom will blink red then green until the minute
value changes, at which time there will again be one red
LED for the hour and one green LED for the minutes
While time is being displayed, the two LEDs I refer
to as the toggle LEDs alternate between the toggle color
and off. The idea behind these LEDs is to simulate
ticking of the clock.
If the clock did nothing but display time, it would
get boring pretty quickly. To prevent boredom, I defined
three events which fire periodically to liven things up.
There is a 10 minute, a 15 minute, and a 30 minute
event. With each 10 minute event, the time display is
suspended and a beautiful rotating color wheel or
rainbow effect is displayed.
With each 15 minute event, the clock goes from
completely dark to brilliance blue in slowly increasing
steps. With each 30 minute event, the full date is
displayed. You have to see these events to appreciate
them. The clock returns to its normal time display as
soon as the event display is completed.
Reading the Date
The date will be displayed in a month/day/year
sequence with unique colors for each quantity. Month
(with a value of 1.. 12) maps directly to the LED display
with January (or month one) at the bottom and
December (or month 12) at the top. The day of the
month (values 1.. 31) will be indicated by a rising dot in
the day color, starting from the bottom LED and
wrapping around the display as many times as
For example, the 29th of the month will loop
through all of the LEDs twice (for a 24 count) and then
light the fifth LED from the bottom to indicate the 29th.
When displaying the year, the bottom LED indicates
2010 with each subsequent year one LED higher.
All aspects of the clock’s operation are controlled
via a 21 key IR remote control; there are no other
buttons or switches to manipulate. The software I wrote
for the clock embodies how I thought the remote
control should work. You can change things if you so
desire since you’ll have access to the source code in the
Arduino sketch which can be found at the article link.
When the clock is first powered up, it immediately
goes into clock mode even though the time or date has
not yet been set. All colors used for display will be set to
defaults coded into the software. NOTE: The clock will
retain the colors you configure for each mode (even if
the clock loses power) and will use these colors until
The clock will remain in clock mode until
interrupted. Hitting the STOP/MODE key (the interrupt
key) on the remote causes the clock mode to be exited
and all LEDs to flash white indicating an interrupt has
occurred and that you have the clock’s attention. The
clock now awaits your command input via the remote
control. Here’s a description of each key:
1 Key — Clicking this key causes the clock to go into
clock mode. The clock will stay in clock mode displaying
the time and date until interrupted.
2 Key — Clicking this key causes the clock to go into
mood light mode where all of the LEDs display a mood
March 2014 37
■ PHOTO 4.