Manual fire alarm system at home?

This could be general smoke alarms installed in you house. This could also be a full functioning fire alarm system. Where you have call points, smoke/heat detectors, bells/sounders/strobes etc. This would be connected through a control panel. SOme intruder alarm systems also facilitate smoke detectors and act as a fire alarm system as well as an intruder alarm system.

Or you could make your own fire alarm. With a light switch, call point, smoke/heat detector with a low voltage (12-24 Volts) power adapter/batteries. Although this could not be very reliable. So try and go for the options above.