level of difficulty:
These are two examples of pickup winders made out of LEGO. They use the motorised Mindstorms , NXT type components to spin the pickup bobbin. I haven't seen any LEGO winders with an automatic travese mechanism yet, but it won't be long before someone builds one.
The first is a pickup unwinder, for despooling a broken pickup, by Scorpion097 .
Rish developed the lego pickup winder further, making a more conventional design with LEGO NXT components for winding pickups.