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The Life and Death of the Bulbdial Clock

An idea that casts a long shadow

My first year of college, I sat in my dorm room staring at the shadow on the wall cast by the sun coming in through the window. I wouldn’t have internet for another year, and I didn’t have a TV, so I often had to come up with creative ways to entertain myself.

So I decided to turn my dorm room into a sundial clock, using the shadow on the wall to tell the time. Every hour, I marked on the wall with a pencil where the shadow was. But I very quickly realized that this was not going to work as well as I hoped.

For one thing, my dorm window faced due West, which meant it didn’t even get sunlight for half the day. For another thing, it occurred to me that as the seasons change and the days get longer or shorter, the shadow would be in a different place each day until it was no longer even remotely accurate — at least until the same day the following year.

That’s when I realized that sundials suck.

Even a properly calibrated sundial that aligns with the Earth’s tilt will still be 14 minutes ahead part of the year and 16 minutes behind later. So they depend on the user referring to something called the Equation of Time to convert sundial time to actual time.

And they still won’t work on a cloudy day.

And if you live in the southern hemisphere, they run backwards.

In 2008, I came up with a solution to this problem. I wrote on my blog about an idea I called “The Bulbdial Clock”:

The Bulbdial Clock has no hands — just one pole in the center of the clock, and three light sources of varying heights which revolve around the pole casting shadows. In the model illustrated above, the light sources are each attached to a ring which rotates around the pole. The innermost ring rotates once per minute, casting a “second hand” shadow. The middle ring rotates once per hour, and casts the “minute hand” shadow. And the outer ring rotates once every 12 hours, casting the “little hand” shadow.

The Bulbdial Clock can be used flat like a traditional sundial, or mounted vertically on a wall. A variation on the design intended for large-scale installation (such as in a museum) involves a pole sticking up in the middle of a room, while the light sources are mounted on the ceiling, shining down on the pole as they rotate around it.

The Bulbdial Clock solves most of the sundial’s problems, but it still has a problem of its own: It doesn’t work in bright light. So the Bulbdial Clock is best suited for dim spaces such as restaurants and nightclubs.

I wrote a lot of “idea” posts back then, and my blog had active commenters who frequently used them as a jumping off point to imagine how they might be even better. I loved that. Sometimes I even held back some of my own thoughts in the hopes that someone else would have the same thought and chime in — a subtle way of fostering conversation in the comments.

Some of the thoughts I held back for this were: What if instead of being white lights, they were red, green, and blue? Then you would get all the primary and secondary colors where the lights overlap, and white in the middle! That would be cool. And if three rotating lights were too complex to build, it could be a ring of lights that turn on and off so there are no moving parts.

Sure enough, the post had barely been up for an hour before someone named Windell Oskey left this comment:

If you used three rings of 60 LEDs each, you could just light up one LED in each of the rings, making it so that you could build this without even using any motors.

I think that I could build this in about an hour. :)

What I didn’t know at the time is that Windell Oskey was exactly the kind of person who would make something like this. He and his wife Lenore ran a business called Evil Mad Scientist which sold electronic kits for projects people could build themselves.

Exactly one year later to the day after my post, Windell shared on the Evil Mad Scientist website that he had built a working prototype using red, green and blue LEDs:

And he sent me an email about it which said in part:

We have also toyed with the idea of making a small kit version of our project-- we make soldering kits. Just say the word and we won't touch it, but I suspect that it might work out nicely if we were to sell a few tens or hundeds of kits and send you a small royalty from each.

I was thrilled by the idea of the Bulbdial Clock being something people could buy and build! And a royalty? I’ll take it!

A quick aside: In the United States, from the time an idea for an invention is publicly disclosed, the inventor has exactly one year to file a patent (or at least a provisional patent which lets you say there’s a “patent pending”). After that grace period, they lose out on any exclusive rights to their invention.

I had no intention of patenting the Bulbdial Clock, but I mention this because there was no legal reason why Windell owed me a royalty. In fact, Evil Mad Scientist projects were all open source, so anyone could make and learn from them without paying a cent. A royalty was their very kind way of recognizing my idea, and I hugely appreciated it.

(It’s also worth noting that if I ever did file a patent application, it may have been invalidated by prior art. Andy Baio left a comment on my original post pointing to an idea someone already shared on halfbakery for a wristwatch with a similar concept.)

By the time Evil Mad Scientist had the Bulbdial Clock kits for sale, the design was refined to this lovely mantel clock:

I was always partial to the transparent model that let you see the circuitry:

The Bulbial Clock went on sale in 2009. And every quarter since then, Windell and Lenore have sent me a royalty check. They got smaller over the years since the kit debuted, but they were always appreciated — and gave me an excuse to keep in touch with Windell and Lenore who are super cool people.

But a few weeks ago they announced that Evil Mad Scientist was acquired by Bantam Tools, a company run by Makerbot founder and 3D printing democratizer Bre Pettis. Together, they are focusing on new products like the NextDraw pen plotter, and moving away from built-it-yourself kits like the Bulbdial Clock.

So that’s wonderful for them! But sadly, it means the Bulbdial Clock kit is no longer available for purchase.

But other Bulbdial Clocks live on!

Since Lenore and Windell made their kit open source, anyone can still build one. You can find all the source code and hardware documentation here.

And in true open source spirit, other people have actually made their own versions of the Bulbdial Clock, sometimes with really cool enhancements. Here are some of my favorites:

An aluminum version by David Bruckenstein

Wow that’s beautiful. This guy actually has a whole business dedicated to building unusual artistic clocks.

A moving version by Wolfgang Friedrich

This is more like my original drawing, so it’s especially cool to see it in action! It was made for a competition called Making Time where you can check out other cool clocks, too.

A refined clock by Solarbotics

I love this one! The Evil Mad Science clock was mantel-sized and only had room for 30 LED lights in each ring, so the second hand actually moved every two seconds rather than every second, and likewise for the minute hand. This one is a bit bigger so it could fit 60 lights and show the time more precisely. Look how beautiful this is:

Solarbotics called it the “Shadow Clock.” They sold it as a kit and made a cool video showing it off:

The Chinook Mall clock, also by Solarbotics

This one is my absolute favorite. The Chinook Mall in Calgary, Alberta has a time capsule embedded in the floor, to be opened on December 31, 2999. When it was first installed in 2000, the cover of the capsule looked like this, with an analog clock in the center:

But being walked on every day, that clock in the center needed frequent repair. So the mall hired the folks from Solarbotics to do maintenance. But Solarbotics had a better idea: Why not replace it with a Bulbdial Clock that has no moving parts?

You can see a gallery of the whole build and replacement process, including videos, on Flickr. But it began with removing the capsule cover:

They replaced the old clock with a beautiful new Bulbdial Clock with Roman numerals and the Chinook Centre logo:

Photo: Solarbotics

And they put it back in the mall where it now sits until New Year’s Eve, 2999.

Or I guess until the mall closes down, which seems a bit more likely, knowing malls.

If we can all learn one thing from this edition of the newsletter, it’s that great things can happen in the comments. So please stop by the comments and say hi!

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