Don't you have a flaw in design - what if module fails? You won't be able to turn on/off light at all...

Update: I've made another board with new components, and now it Works every time, i took the old board and added a Decoupling-Capacitor, now it Works about 6/10 times. Edit: I've resawdered the Wireless chip (FK 16.ONU) and now i got it to 8/10 times. Edit2: I added a Decoupling-Capacitor of 47UF insted of the 4,7 10/10 times.

@Gutz2001 Instructables maybe it can help