silent walkiw talkie alarm

[Highlander]

You can get mats to stop dogs jumping over gates etc,... you place them at the point where the dog jumps from, when he goes on the mat he gets a small electric shock.

I wouldn't dream of using one for that purpose, but its the kind of thing that could easily be adapted

I have been trying to find one but as yet I cant,.. will keep looking, I saw them on an American show, so might not be able to get them here