This clock has a default mode where a white LED fades up and
down very slowly at the bottom of the white translucent
section. If you wave your hand anywhere near the top
or sides it "wakes up" and starts displaying time by
lighting up LEDs in sequence from the bottom. First it
shows the number of hours, and then the number of minutes in
five minute increments. So for instance, to show a
time of 3:20 it would first light three LEDs, pause
and then light for LEDs. At the bottom of this page is
a video that shows how it works and how it was made.
This is the ninth collaborative clock project that Dave and
I have completed. The original concept was for a
circular clock with 12 LED rings that would show the number
of minutes at each our position. We later explored
using straight lines of LEDs for each clock hand position,
but finally simplified the whole design down to its
essential, simple form.
Dave does these excellent CAD renderings for every idea that he or I develop.
But what is always interesting to both of us is that his final CAD rendering
looks a great deal like what I end up fabricating. This clock is no
exception, and his rendering (at right) is so accurate that it could have been done after
the fact rather than before. Or may be, it's that I'm very good at
following his renderings!
The base is fabricated from a heavy aluminum cylinder that was 4 inches
in diameter and around 5 inches high. I was able to machine both ends, but
my mini metal lathe was too small to finish up the outside surface, so I took
it over to Jason who lives nearby - he and has a large machine lathe that he
used to clean up the
outside surface. It took over 8 hours to machine this cylinder to make the recesses at the top and bottom, and holes for the buttons
and power jack on the back. I am teaching myself metal machining
in this project was extremely enjoyable for me.
Here is a view of the final completed base fully machined. The recess in
the bottom holds the acrylic panel that holds the electronics, and the holes are for
the hour and minute set buttons and the DC power jack. I coated the
aluminum with shellac to preserve the finish.
The electronics for this clock were relatively simple and I was able to hand
wire it using a vintage technique known as wire wrapping. Back in the
1980s I used to use this technique to build prototypes all the time! The
code development was similarly easy because I was able to use boilerplate code
that I had written for the real-time clock functions in previous clocks.
Also, the DotStar LEDs in this project are very easy to program, each one is a
smart LED that I send brightness info to.
I made a very detailed video that shows the clock in action and how I made it.
As with each of these projects, I get to live with the final product for a few
days before I ship it off to Dave in North Carolina.
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