Abstract: A combined doorbell and smoke detection device includes a housing that has monolithically formed sides. One side includes openings formed adjacent to the housing top corners for receiving fasteners therethrough. Nested within the housing are a door bell chime, a first control unit, a carbon monoxide smoke detector, and an ionization smoke detector. A second control unit is coupled to the carbon monoxide and ionization smoke detectors, and includes an amplifier. A power interrupt diverting switch is disposed within the housing and is mated to an external power source. An internal power supply source is nested within the housing and is coupled to the power interrupt diverting switch. A transformer is coupled to the power interrupt diverting switch, and the first and second control units for converting a first voltage level to a second voltage level transmitted to the first and second control units respectively.