What kind of gun is not lethal but can stun/immobilise a victim? (specifically i'm thinking of home security)

It is specifically meant for personal and home safety. Should not be lethal - hence free from hassles of licensing but have power to stun or immobilise victims; it should be simple and cost-effective enough to make, preferably on our own; it may use chemicals, minor explosives or electronic devices etc but should... show more It is specifically meant for personal and home safety. Should not be lethal - hence free from hassles of licensing but have power to stun or immobilise victims; it should be simple and cost-effective enough to make, preferably on our own; it may use chemicals, minor explosives or electronic devices etc but should not be dangerous to keep it; also handy enough to carry around
Update: It should have a reach of at least 30 meters.
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