NOVELTY - A sobriety interlock device comprising handset having gas intake channel; breath sampling housing (30) enclosed within the handset and having gas sampling channel; fuel cell (64) along the gas sampling channel; pressure transducer (46) within the handset; microprocessor within the handset; and power source coupled to the handset, is new.    USE - The device can be used in vehicles and motorized machinery apparatus for detecting presence of alcohol in breath sample introduced into the device and for controlling the device output in response to predetermined threshold level being exceeded (claimed).    ADVANTAGE - The invention is provided with water filter that eliminates moisture from the breath vapor avoiding moisture saturation of the fuel cell. It provides improved temperature monitoring to ensure that the device works properly in cold weather climates.    DETAILED DESCRIPTION - The sobriety interlock device comprises handset having gas intake channel for receiving breath sample; breath sampling housing enclosed within the handset and having gas sampling channel in axial alignment with the handset gas intake channel; fuel cell along the gas sampling channel for measuring an alcohol vapor value of the breath sample; pressure transducer within the handset in fluid communication with the gas sampling channel for measuring pressure value of the breath sample; microprocessor within the handset in electrical communication with the fuel cell and the pressure transducer, and contains an executable algorithm for determining a measured blood alcohol content of the breath sample through an offset adjustment of the measured alcohol vapor value in relation to the measured breath sample pressure value, the microprocessor applying a signal to the output of the interlock device dependent on the results of the measured blood alcohol content as compared to the predetermined threshold level; and power source coupled to the handset.    DESCRIPTION OF DRAWING(S) - The figure is a flow diagram illustrating the manner in which air flows through the handset and the breath sampling housing.    Display screen (12)    Breath sampling housing (30)    Pressure transducer (46)    Capillary tube (52)    Fuel cell (64)    Passageway (70)    Water filter (72)    Solenoid valve (98)    Housing sensor (122)    Housing heater (124)    Base unit (138)