I think this is what I'll be going with. Shifted the antennae around a bit, then took the crystal from the Meridia quest, figured out how to slap a (somewhat overboard) glow effect onto it, and shrunk it down to fit into the assembly at the back of the helmet. We'll just say it's a fragment of Meridia's realm or something that the Dwarves used for a power source. The contrast in color and intensity between its glow and that of the button meshes adds a nice bit of visual depth, too.