We need a small energy source. I used CR2032 batteries which have 3 Volts each. There are different sizes available. The first two digits are the width of the battery, the second two, the height. So, a CR2032 is 20mm wide and 3,2mm thick. A CR2016 is just 1,6mm thick but has less power. I used the strongest battery that fits in the base.
We have to make room for this…
I used a drill we call „Forstnerbohrer“ in German. The translation said it´s called a „Forstner bit“ in English. Mine has a diameter of 22mm, which is the perfect size for the batteries.
Don´t drill too deep, we want just enough room for the batteries and the magnets.
I used 6x1mm round magnets. The initial hole from the forster bit must be enlarged with a 6mm drill to fit the magnets.
Fits perfectly.
I glued the magnets in place with superglue. Then I cut two pieces from a wooden coffee stirrer for better stability. For the side, I used 5x2mm square magnets and some old batteries to keep the magnets in the perfect position.
Next step is to drill two small holes for the wiring.