I read that you can build a piezo transducer pickup for an acoustic guitar for less than $10. Of course, it would work just as well in a Ukulele. $$$ don't work here, so I priced up the parts I would need from the Maplin online store. A piezo buzzer, a 1/4" jack socket and a short length of shielded single core cable. It came to £2.41, so I ordered the bits. This is the piezo unit. If it works, I might make another for the 12-string.