What sort of technology could one fit into something the size of The doctor's screwdriver? I was thinking about maybe a universal remote, an rf/if one maybe a small laser (100-500 mW) maybe a function generator with an antenna and a frequency generator with a speaker or something, just to make it be sonic. Making it clear, not just a prop but with some interesting functions. Any suggestions? Also if possible anything that can be salvaged from old equipment and electronics that can be used please say it.