Hi Bob,
I’ve been thinking about what to do next. One idea is turning the
BangDrum space in Mossley into a huge freaking drum machine, using
piezos as sensors under each fabric-cutting worktable and LED strip as
the output. The sensorts would have to run off (say) 2 AAs for a long
time, so I was wondering about using a ATTiny and one of the nRFs as a
remote wireless sensor - which is pretty much what you’ve already done.
If not that, they have a nice steel staircase into the space, piezos
under some of the steps would work rather well 
How did you get on with your nRF24L01+ boards? Are you intending to run
them off batteries, and if so, what sort of life do you expect?
Thanks,
Alan Burlison