This simple hardware project allows a medical doctor to comfortably and reliably signal for the patients sitting in the waiting room that they can enter the examining room.
The small controller periodically sends signals for the receiver and waits for conformation that the message has arrived. When no conformation is received the yellow LED shows that there is a problem with the connection and the people in the other room probably doesn’t see the same as the controller is showing.
The receiver was fit inside a regular ceiling lamp and uses two highly efficient colored LED bulbs that can tolerate the frequent switching cycles.
