Smoke detector

A device for detecting smoke comprising:

• a housing having vents for allowing ingress of said smoke into the housing;
• a sensor chamber disposed within the housing, said sensor chamber defined by a first chamber part and a second chamber part and having vents for allowing ingress of said smoke into the sensor chamber;
• a sensor mounted within the sensor chamber;
• an alarm circuit including a detector for detecting said smoke when sensed by the sensor;
• and
• a printed circuit board supported by the chamber parts so that it is partially sandwiched between the first chamber part and the second chamber part, such that an edge thereof extends part way into said sensor chamber so as to divide the sensor chamber into two portions, one disposed above the printed circuit board and the other below the printed circuit board, wherein said printed circuit board has the alarm circuit and the sensor mounted thereon and the sensor is mounted on, near or adjacent to said edge.