NRF.sleep() totally turns off bluetooth, which you probably don't want :)
This is exactly what i've tried to do to save some battery capacity.
Unfortunately the Puck doesn't show up again after NFR.wake()
Do I have to do anything else after enabling bluetooth again?
Do I have to setup advertisements using NRF.setServices / NRF.setAdvertising?
just after NRF.wake() fixed it :)