This is a decorative lamp, or a decorative piece as such. It started out as a simple low-polygon cone in Blender, but I ended up with this shape after experimenting with the subdivision surface modifier and a lot of manual pushing and pulling of vertices.

The shape screws onto a support that I provide in several variations: a plain one, which should accept a standard tea light (obviously, an electrical one), and two versions that can be fitted with a microUSB socket to power anything else that works on 5 V. One of these has extra tabs that are dimensioned for the LED driver board that I used.

In my build, the microUSB socket powers 4 straw-hat (omnidirectional) LEDs through an old LED driver that I used in an experimental bicycle light long ago. It is a voltage-boosting current source based on the TPS61040 from TI. The circuit board is an unsightly mess but it still works, and I finally found a second use for it. The nice thing about a current source like this, is that any number of LEDs (within a certain range of course) can be connected, and it will always pump about 24 mA through each of them.

This thing has the curious property that even if the light source is perfectly stable, I often get an impression that it flickers. This is probably due to the pattern of the ridges, or maybe I have just inhaled too many plastic fumes…

The model shown in the photos is a prototype. The final model has a more gradual transition between the deeper grooves and the solid top and bottom ends, so it should look even nicer.