The springs are sections from a spring from an old wind up clock wich had snapped.
I use toothpicks as arrows.
The wire i used was some I had lying around.
The parts are printed with my HE 3D rerprap prusa I3 3D printer.
I use a little spring to push the pushbutton back to it's original place after its is pushed.
The shaft where the triggers rototate around is made out of a nail.
Everything is glued together with two-componend glue.
STL-files can be found here: https://www.thingiverse.com/thing:2710472