I have three bilge pumps in my boat on three switches. They all have an 'auto' position with float switches. When (if) they go on, a light goes on in the switch. I would like to add an audio alarm to this. Has anyone done this? Any suggestions on what to use? My old boat had something like this, and it was a very small device that was very load and high pitched. I would like to do something similar. I think I will have to have three of these, unless there is some way to isolate the switched with a diode or something. Functionally I would be fine if a single alarm sounded if any of them actuated.