This invention relates to apparatus for estimating body alcohol concentration from personal body characteristics. For example, a calculator 10 has a keyboard 12 through which the user can input information concerning his sex, body weight, degree of fat, food consumption, alcohol consumption and the timing of these last two events. Depending on the mode into which the apparatus is set, the user can be told his maximum body alcohol concentration, how much more he may drink before reaching a legal limit, or when he may achieve the legal limit if he drinks no more.

A system and method to prevent a human being from operating a motor vehicle if the human being is intoxicated or under the effects of particular hallucinating drugs that uses a galvanic detector that can measure epidermal (skin) elements of a human being such as alcohol content, sweat and temperature continuously in conjunction with circuitry and logic circuits that connect to the vehicle's ignition system that only allow the vehicle to be operated when certain temperature sensing conditions are met and certain conditions requiring no alcohol are met otherwise the vehicle will be turned off. In an alternate embodiment, a glove could be used for epidermal measurements that is also connected to the sensing circuits.

A sobriety interlock for a machine such as a vehicle operates in either an interlock mode or a BYPASS mode. In the INTERLOCK mode, a breath sobriety test must be passed before the machine can be started, while in the BYPASS mode, a breath test is not required to start the machine. When the system is powered up, it operates in the INTERLOCK mode for a predetermined period, preferably about 12 hours before automatically beginning operation in the BYPASS mode. From the BYPASS mode, INTERLOCK mode operation can be selected at any time by actuating a switch which locks in INTERLOCK mode operation for at least the predetermined period of time.

Disclosed is a system both apparatus and method, for analyzing a breath sample (22). A transducer (24) senses the pressure, temperature and humidity of the breath sample and in response generates a breath signature signal (26). A sensor (28) detects the alcohol content of the breath sample and in response generates an alcohol signal (30). Also included is a breath reference (32), and an alcohol reference (34) which includes an alcohol threshold level (36). A first comparator (38) compares the breath signature signal with the breath reference, and in response generates either a valid signal (40) if the signals substantially match or an invalid signal (44) if the signals do not substantially match. A second comparator compares the alcohol signal with the alcohol reference, and in response generates either a passing signal or a failing signal depending on whether or not the threshold level is exceeded.

A sobriety interlock system prevents a vehicle or other equipment from being started unless the identity of a designated operator is confirmed by the system and the operator passes a breath sobriety test. The designated operator is trained to perform a physical act, the successful completion of which can be determined by the system and which requires at least a predetermined number, N, of attempts to learn. A necessary precondition for starting the vehicle is satisfied when the system determines that the identity-confirming act has been performed in fewer than N attempts.