System and method for preventing unauthorized or impaired operation of a motor
vehicle by requiring a potential operator to sequentially energize several vehicle
devices, within a set time period, prior to placing the vehicle ignition into a
start position. The system includes a sequencing mechanism comprising an array
of J-K flip-flops in a daisy chain configuration and an R-C timer mechanism. Logic
outputs from the sequencing mechanism and the timer mechanism are fed to a NAND
gate operating as a logic decoder that is used to control the vehicle ignition
circuit. Only if all the inputs to the logic decoder are "go" will the output signal
allow the ignition circuit to close. A sensory indicator may alert the potential
operator as to the condition of the decoder output. An unauthorized user is inhibited
from operating the motor vehicle because the performance sequence is unknown to
him/her. Slower reflex times or impaired motor skills may prevent an impaired operator
from performing the proper sequence within the predetermined time period.
