Reversed sundial still shows the time

The Dutch word for sundial, sundialcan literally be translated into “Sun Pointer” according to [illusionmanager] – and he took that literal translation literally, building an inverted sundial so that it would always know the precise location of our local star, even if it is enclosed by clouds or the rest of the planet.

The electronics are not terribly complicated: an ESP32 development board, an RTC board and a few steppers. But the craftsmanship is, as usual, in favor [illusionmanager]flawless. You might guess that one motor controls the altitude and the other controls the azimuth of the LED filament pointer (a nice find from AliExpress), but you would be wrong.

This is more like an equatorial mount, in that the shaft on which the arrow turns is bent at a 23.5 degree angle. A spring steel wire connects the arrow to one stepper via the hollow shaft to drive it all day long. The second stepper rotates the axis to keep the axis correctly aligned as the Earth revolves around the sun.

Anyway, you can get an arrow that always points to the sun, but this is much more elegant than an alt-az mount would have been, at the cost of a more fiddly construction. Considering the existence of the planetary clock we showed of him earlier, it’s safe to say so [illusionmanager] is not afraid of a clumsy construction. If you do it this way, you can also read the ticks on the base just like you would with a real sundial, taking it from discussion piece to (semi) useful clock.