Synesthetic Clock

I thought my wife would be impressed by my rainbow clock, but she wasn’t – the colors were all wrong.  To me, the spectrum of colors rising from lowest frequency to highest made perfect sense, but my wife perceives numbers as colors.  So I agreed to create a clock with the “proper” colors for each digit.

I decided to use a projection display, as illustrated here.  The displays I found are huge; the digits are almost 2 inches (5 cm) high.  The internal components are pretty complex too; here is a cut-away view of one of the projection units.

This display has four different lens arrays.  Here are the first layers, in order

Here are the last layers, also in order

I used 10 different colored LEDs for the lamps, and packaged the unit together.  We have motorized curtains which are supposed to close in the morning and open about noon – the timer is some ugly cheesy thing.  I decided to replace the curtain timer with this clock.  The turrets on the left hand size contain IR LEDs that we can point to the IR pickups for the curtain motors.

As with the emoticlock, I created the projection screen by sanding down a piece of clear plexiglass.  Here is a picture of the back of the unit, showing the wiring.  The orange goo is tack putty to keep the LED boards in place.  It is ugly but no-one looks back there (normally).

It took me a while to figure out how to drive the projection displays properly: it takes a big light source.  Eventually I managed to create an array of four 5mm LEDs per lens, which gives an even illumination.  Here is a detail which shows the LED arrangement.

I replaced the transparencies that came with my displays with ones I created, by printing on transparency film.  My inkjet printer must have been running out of ink, because the coating came out uneven.  I decided that I liked the scratchy feel of the display so I kept it.  Here is 7:55 pm

And here is 12:48 pm