I'm making a cyborg/android type costume, and I'd like to rig something to produce that servo camerafocus type (vzzt vzzt ) sound. Without electronics. What could I use?
Set up a hand crank, striker and two resonators as shown in the attached drawing should create the sound effect you are looking for without the use of electronics.
As you move the hand crank the axle turns the disk on which a striker has been fastened. As the striker passes the resonator (fixed in place) it will stroke the resonator to emit its characteristic sound.
Place two resonators 180 degrees apart and you should get your vzzt vzzt sound effect.
Note: you will have to play with the length and width of the resonartors to get the right sound out of it.
I remember some hand-operated tin toys with spinning parts. Probably close. Alternatively you might want to try some of those hand copter toys where you crank a retracting cord in order to launch a plastic wheel with blades into the air. Just omit the copter wheel, and the springed crank should like be good for that kind of noise. If not, gluing somethink small and floppy on the axle might help. Don't glue the copter wheel, though: if it can't disengage, it will likely break the launcher pretty fast.