Following a few older threads,I made one.I went and bought
a piezo transducer from a local electronics shop,cost 15 pence
(Whatever that is is dollars?) Mounted it on the end of a guitar
lead as a permanent fix,and voila.It fixes to any uke with a very
thin circle of Blu Tak that I laid around the 'rim'. Okay it's not
perfect,but it captures every note and strum,and for the price
was a worthwhile experiment!