Wedding ring glows, if you take the hand

American engineer Ben Cokes (Ben Kokes), intending to offer the hand and heart of his girlfriend, made a wedding ring with a resonant transformer and three small LEDs among the gems. The idea is that the bride's ring starts to glow when the groom takes her hand.

The whole process is documented in the author's blog. First of all, the project is created in the AutoCAD program for 3D modeling: you need to calculate that after adding details the ring has the correct internal diameter, the sizes of the stones and the recesses for them, as well as the distance between the recesses.


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The ring of the desired diameter is machined from a titanium blank.



Drill holes are made for precious stones.



The workpiece is cut and polished.



Then the stones are carefully glued.



To make the illumination, the author has implemented a resonant transformer , which transmits wireless energy between two windings, each of which is included in an oscillating circuit at close resonant frequencies. Ben Cokes introduced a copper winding with a capacitor into the ring, three LEDs are connected in parallel to the circuit. With a capacitor of 820 pF, the resonant frequency was 1.5 MHz.



Winding the transmitter with a power source the groom must wear on his hand. The design of the transmitter is borrowed here . The device came out quite massive, but you can still hide it in the sleeve.









The effect is shown in the video.



The Cox blog has step-by-step instructions on how to carve such a ring of a given diameter, make indentations for stones, etc.

All the work took the author five months: from January to May 2013. It has been tested several options for mounting stones and the thickness of the ring. Many test versions of the ring had to be thrown out.



Ready result close up.



PS The author wanted to surprise the girl with a luminous ring, and the next day go with her to the jewelry salon and buy something solid. To his surprise, the girl refused to change the decoration, and only asked to slightly increase the inner diameter. The finger was 15.72 mm, not 15.6 mm, as Ben had suggested, so the ring came out a little cramped.