Hello all,
Looking to build a custom alarm system. My boat system is 12v DC .
I would like to incorporate a siren, outdoor spreader light (existing) add a flasher to the lights. I installed new very bright spreader lights, they
The catch... I would install 2 manual toggle switches to activate the alarm 1 in each bedroom . ... i would like to have the kill switch for the alarm in the engine room very well hidden.

purpose: intruder boards the boat at night, upon hearing this either of the 2 bedrooms would have a toggle switch to activate the alarm. if the intruders force their way in, they could easily find the switch and turn it off. I do not want this to happen so I wish to make it so that once activated only a 3rd switch can cancel the alarm and that would be very difficult to find. We can just play stupid and say the switches in the bedrooms wont turn it off or its not working...

I have basic 12v knowledge and would ask for help designing the circuit, once I know what components are required and some guidance I should be good to go....
I have the alarm horn, switches and lots of relays. will need to get the rest. I would build the system and test at home prior to installing in the Caribbean where the boat is.

I hope enough information was given above on the project.
Any advice would be greatly appreciated.
Thank you in advance...

 

A dual-coil latching relay would work for that (example).
The bedroom switches (connected in parallel) would set the relay and the engine switch would reset it.

 

A dual-coil latching relay would work for that (example).
The bedroom switches (connected in parallel) would set the relay and the engine switch would reset it.

thank you,
I'm looking it up now...

 

You could also use a standard relay connected as a latching relay as shown below:
B1 would be in the bedroom (two switches in parallel) and B2 in the engine room.
Note that B1 is normally open and B2 is normally closed.

 

This is one way to do it.
https://tinyurl.com/2aerk7wm
Click on the middle of the switches to activate light.

 

There is no need at all for a dual coil relay. I have designed alarms for other folks that only used three terminal HORN RELAYS. And a visible switch would be an OK trigger because it could not switch off that alarm.
But I am suggesting a trigger for the alarm the moment anyone climbs onto the boat, or touches the "Rat Line" if the boat has one. Then lots of bright lights and loud sirens sounding even before any actually get onto the deck.
For actual physical protection, a pump action shotgun with the first two shells being magnum blanks. A blinding muzzle flash and powder burns will deter most bad guys without killing them.

 

There is no need at all for a dual coil relay. I have designed alarms for other folks that only used three terminal HORN RELAYS. And a visible switch would be an OK trigger because it could not switch off that alarm.
But I am suggesting a trigger for the alarm the moment anyone climbs onto the boat, or touches the "Rat Line" if the boat has one. Then lots of bright lights and loud sirens sounding even before any actually get onto the deck.
For actual physical protection, a pump action shotgun with the first two shells being magnum blanks. A blinding muzzle flash and powder burns will deter most bad guys without killing them.

You could also use a standard relay connected as a latching relay as shown below:
B1 would be in the bedroom (two switches in parallel) and B2 in the engine room.
Note that B1 is normally open and B2 is normally closed.

View attachment 328004

Makes good sense. Seems pretty straight forward...
Thanks for the ideal ...

 

Makes good sense. Seems pretty straight forward...
Thanks for the ideal ...

since it is an older boat it only really has one entrance due to the semi-solid enclosure. One must enter through the rear transom and climb in via the captain seat. I have been told this is the perfect place for a pressure mat under the cushion with a 2 prong plug under the seat they would not see it before its to late... this would work with your circuit also... as for weapons in the Caribbean, a guy was caught with a salt gun to kill flies like a plastic toy. He was arrested. being caught with a gun is an automatic 10 years in prison. As of late there were 2 people (Americans) caught at the airport with 1 bullet in a bag by accident and are in jail waiting for trial... could be 10 years this was in Turks and cacaos. Bahamas is the same. weapons are not a good idea..... but I would if I could...
once again, thanks for your input.
I'm going to hit the electronic supply tomorrow.

 

This is one way to do it.
https://tinyurl.com/2aerk7wm
Click on the middle of the switches to activate light.

I like it, this is starting to make sense.
thanks for the diagram, it is quite helpful.

 

thank you,
I'm looking it up now...

I like your project collection. giving me some ideals....
30 years of being a millwright and now I'm thinking of taking electrical course.. lots of electrical issues on boats.lol