Here is my vesrion of Sonic Trowel from Dr Who designed for a fried. There are two versions, regular one and LED version.
For LED please use 3mm blue LED, micro on'off switch and CR2032 3V battery. There is enough room to put battery holder inside the handle, feed the wire through and then connect to LED. The two pieces of handle should slot one inside another so you can change the battery when it's flat.
Physics, 3D printing, Programming, Astronomy and Sci-fi - that's me \//