Patent ID: 6057768
Filing Date: 2000-05-02
Classification: G08B

Abstract:
An apparatus for preventing a driver from falling asleep, comprising:a housing;a gravity actuated sensor, placed within the housing, for sensing when the driver's head is tilted, and sending a detect signal;a vibrator, placed within the housing, for producing low frequency vibrations which irritate the driver and prevent the driver from falling asleep;a vibrator driver, placed within the housing and coupled to the vibrator and to the gravity actuated sensor, for activating the vibrator after receiving a detect signal;a power supply means, placed within the housing, coupled to the gravity actuated sensor and to the vibrator driver;a detect signal driver connected between the gravity actuated sensor and the vibrator for smoothing the detect signal;wherein the apparatus has at least two electrodes, wherein the gravity actuated sensor closes an electrical circuit across the electrodes when it senses that the apparatus is in a predetermined range of deviation from the horizontal;wherein the detect signal driver comprises: a first capacitor, a first resistor, a second resistor, a pull-up resistor and a first comparator, having positive input, a negative input and output; wherein the first and second resistor form a first resistive voltage divider;wherein the vibrator driver comprises: a bias resistor, a transistor, a diode and a plurality of outputs coupled to the vibrator inputs;wherein a first electrode is coupled to the ground and a second electrode is coupled to the negative input of the first comparator, and to one end of the pull-up resistor; wherein the other end of the pull-up resistor is coupled to the power supply;wherein one end of the first resistor is coupled to the power supply and the other end is coupled to the positive input of the first comparator; wherein one end of the second resistor is coupled to the ground and the other end is coupled to the positive input of the first comparator;wherein the output of the first comparator is coupled to one end of the bias resistor and the other end of the bias resistor is coupled to the base of the transistor; wherein the collector of the transistor is coupled to the first input of the vibrator; andwherein the power supply is coupled to the second input of the vibrator; wherein the cathode of the diode is coupled to the power supply and the anode of the diode is coupled to the collector of the transistor.