The Life and Death of the Bulbdial Clock (opens in new tab)

The buried detail that Evil Mad Scientist was acquired by Bantam Tools deserves an article on its own IMO. I find it sad that such a nifty small (and seemingly very personal) business would get gobbled up (though I would be happy if they proved me wrong about the typical fate of acquired companies!).

> So they depend on the user referring to something called the Equation of Time to convert sundial time to actual time.

Not necessarily, or at least without explicit calculation. Good sundials are marked with a calendar that does that for you. Large analemmatic dials have places marked for each month where you stand the gnomon, which can be a person. There is one by the river in Stratford Upon Avon

https://www.geograph.org.uk/photo/6232719

There are also dials that include a kind of circular slide rule that implements the equation of time:

http://www.short-humour.org.uk/Heliochronometer/Heliochronom...

I have a Bulbdial clock sitting on the mantel. I bought the kit around when they first came out but only got around to building it a few years ago. Recently when my niece stayed over, she slept in the living room, and she asked for "a nightlight". I turned up the brightness setting to provide a multicolored glow.

Lots of comments here about sundials and the equation of time, responding to OP comment that sundials suck.

The actual issue is that sundials reflect the movement of the sun, whereas we mainly use an averaged out mean time to describe when it is noon. Solar noon (when the sun is at it's highest point) is sometimes ahead of mean time noon, sometimes behind it. This is due to the movement of the earth around the sun (including whether the earth is east or west of the sun looking down from the above the sun), the earth's axial tilt, and your latitude. However, the variation is entirely predictable, as encapsulated in the so-called equation of time, which shows the variation that needs to be applied to get mean noon. Of course, none of this really matters if you aren't bothered about synchronising geographically distributed clocks, time zones, etc.

As an example of the other weirdnesses that can result from using solar time, consider how day length changes as we go from the shortest to the longest day. Where I am in the southern UK, sunrise continues to get later until about two weeks after the shortest day, and the major change of day length (at that time of year) is in the evening. This is the same effect captured by the equation of time and reflects the fact that we are on a wobbly planet that doesn't have a perfectly circular, perfectly vertical orbit around the sun.

[Edit - minor rewording for clarity]

With RGB LED strips so common these days, you could make one pretty easily by getting a high density strip, measuring the spacing of the LEDs, and calculating the correct diameter for the strip's pitch. Doing some quick calculations, an LED strip that is 60 LEDs per meter would require a clock that is 16cm in radius, which would be a nice size for a wall clock!

Only vaguely related to the article, but I really enjoy the notion that the sun is a bad clock - like, that the time a sundial tells is unreliable.

It doesn’t match the other clock we made, sure, but boy that would’ve been a weird thing to explain to any human at all 200 years ago.

> the sundial, can be ahead (fast) by as much as 16 min 33 s (around 3 November), or behind (slow) by as much as 14 min 6 s (around 11 February).

wow, I never knew!

> Why not replace it with a Bulbdial Clock that has no moving parts?

I missed the part where they explained how you get a moving shadow, without either moving posts or moving lights.

Great article! I'm especially interested because I make weird clocks & digital displays too.

Https://digitalhorology.com

Cool idea, but if you are going to use lights to cast shadows to (in some way) replicate a sundial, then use a 24-hour face ffs. The 12-hour analogue clockface is a dumb abstraction to get stuck on if you are going to the trouble of re-imagining how to build a clock.

Also, sundials don't suck.