Drowsiness alarm system for a vehicle

Claim 2

A drowsiness alarm system for a vehicle for producing a warning in the event of driver drowsiness as determined from vehicle steering changes, characterized by (10) (a) an alarm unit which produces an alarm in a predetermined form in response to a pulse inputted thereto; (1) (b) a steering angle sensor which generates a signal indicative of the angle at which a steering wheel is turned with respect to an equilibrium position; (2) (c) a steering angle detection circuit, (1) connected to said steering angle sensor, which outputs a first pulse whenever the range of change of the vehicle steering angle exceeds a predetermined amount; and (13) (d) a quick steering detection circuit, (2) connected to said steering angle detection circuit, for (10) outputting a second pulse to said alarm unit whenever the number of the first pulses inputted thereto within a predetermined period of time of one another sequentially reaches a first predetermined number.

Claim 3

A drowsiness alarm system for a vehicle for providing a warning in the event of driver drowsiness as determined from vehicle steering changes, characterized by (a) an alarm unit which produces an alarm in a predetermined form in response to a pulse inputted thereto; (b) a steering angle sensor which generates a signal indicative of the angle at which a steering wheel is turned with respect to an equilibrium position; (2) (c) a steering. angle detection circuit, (1 ) connected to said steering angle sensor, which outputs a first pulse whenever a range of change in the vehicle steering angle exceeds a predetermined amount; and (18) (d) a frequency of steering detection circuit, (2) connected to said steering angle detection circuit, for outputting a third pulse to said alarm unit whenever the number of the first pulses from said steering angle (2) detection circuit within a first predetermined period of time of one another sequentially and within a second predetermined period of time altogether exceeds a secnd predetermined number.

Claim 4

A drowsiness alarm system for a vehicle for providing a warning in the event of driver drowsiness as determined from vehicle steering changes, characterized by (a) an alarm unit which produces an alarm in a predetermined form in response to a pulse inputted thereto; (b) a steering angle sensor which generates a signal indicative of the angle at which a steering wheel is turned with respect to an equilibrium position; (2) (c) a steering. angle detection circuit, (1 ) connected to said steering angle sensor, which outputs a first pulse whenever a range of change in the vehicle steering angle exceeds a predetermined amount; and (18) (d) a frequency of steering detection circuit, (2) connected to said steering angle detection circuit, for outputting a third pulse to said alarm unit whenever the number of the first pulses from said steering angle (2) detection circuit within a first predetermined period of time of one another sequentially and within a second predetermined period of time altogether exceeds a secnd predetermined number.

Claim 5

A drowsiness alarm system for a vehicle as set forth in claim 1, characterized by (18) (a) a frequency of steering detection circuit, (2) connected between said steering angle detection circuit and (10) said alarm unit, which outputs a third pulse to said alarm unit whenever the number of the first pulses from said steering angle detection circuit within a first predetermined period of time of one another sequentially and within a second predetermined period of time altogether exceeds a second predetermined number (10) whereby the alarm unit provides the alarm indication in response to either second or third pulses from said quick steering and frequency of steering detection circuits.

Claim 6

A drowsiness alarm system for a vehicle as set forth in claim 1, characterized by (16) (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a predetermined value; and (17) (b) a first AND gate, one of the two input terminals of which is connected to said quick steering (13) detection circuit, the other input terminal of which is (16) connected to said vehicle speed sensor, and the output (10) terminal of which is connected to said alarm unit for enabling the second pulse from said quick steering detection circuit to pass therethrough to said alarm unit only when said vehicle speed sensor sends the first high-level voltage signal thereto.

Claim 7

A drowsiness alarm system for a vehicle as set forth in claim 1, characterized by (16) (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a predetermined value; and (b) a first AND gate, one of the two input terminals of which is connected to said steering angle (2) detection circuit, the other input terminal of which is (16) connected to said vehicle speed sensor, and the output terminal of which is connected to said quick steering (13) detection circuit for enabling the first pulse from said steering angle detection circuit to pass therethrough to said quick steering detection circuit only when said vehicle speed sensor sends the first high-level voltage signal thereto.

Claim 8

A drowsiness alarm system for a vehicle as set forth in claim 2, characterized by (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a predetermined value; and (b) a first AND gate, one of the two input terminals of which is connected to said frequency of (18) steering detection circuit, the other input terminal of (16) which is connected to said vehicle speed sensor, and the output terminal of which is connected to said alarm unit(10) for enabling the third pulse from said frequency of steering detection circuit to pass therethrough to said alarm unit only when said vehicle speed sensor sends the first high-level voltage signal thereto.

Claim 9

A drowsiness alarm system for a vehicle as set forth in claim 2 , characterized by (16) (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a predetermined value; and (b) a first AND gate, one of the two input terminals of which is connected to said steering angle (2) detection circuit, the other input terminal of which is connected to said vehicle speed sensor, and the output terminal of which is connected to said frequency of (18) steering detection circuit for enabling the first pulse from said steering angle detection circuit to pass therethrough to said frequency of steering detection (18) circuit only when said vehicle speed sensor sends the first high-level voltage signal thereto.

Claim 10

A drowsiness alarm system for a vehicle as set forth in claim 3, wherein the output terminals of both said quick steering and frequency of steering detection circuits (13,18) (10) are connected to said alarm unit via a first OR gate and which is characterized by (16) (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a predetermined value; and (17) (b) a first AND gate, one of the two input terminals of which is connected to said steering angle (2) detection circuit, the other input terminal of which (16) connected to said vehicle speed sensor and an output terminal of which is connected to both said quick steering (13,18) and frequency of steering angle detection circuits, for enabling the first pulse from said steering angle detection circuit to pass therethrough to both said quick steering and frequency of steering angle detection circuits only when said vehicle speed sensor sends the first high-level voltage signal thereto..

Claim 11

A drowsiness alarm system for a vehicle as set forth in claim 3, wherein the output terminals of both said quick steering and frequency of steering detection circuits (13,18) are connected together to a first OR gate (40) and which is characterized by (16) (a) a vehicle speed sensor which outputs a first high-level voltage signal when the vehicle speed exceeds a .predetermined value; and (17) (b) a first AND gate, one of the two input terminals of which is connected to the output terminal of (40) said first OR gate, the other input terminal of which (16) connected to said vehicle speed sensor, and an output (10) terminal of which is connected to said alarm unit, for enabling the second and third pulses from said quick steering and said frequency of steering detection circuits (13,18) (40) respectively via said first OR gate to pass therethrough to said alarm unit only when said vehicle speed sensor sends the first high-level voltage signal thereto.

Claim 12

A drowsiness alarm system for a vehicle as set forth in claim 1, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy from various vehicle operating conditions except a vehicle steering condition; and (67) (b) a second AND gate, one of the two input terminals of which is connected to said steering angle (2) detection circuit, the other input terminal of which is (101) connected to said vehicle condition responsive circuit, and an output terminal of which is connected to said quick (13) steering detection circuit for enabling the first pulse (2) from said steering angle detection circuit to pass therethrough to said quick steering detection circuit (13) only when said vehicle condition responsive circuit (101) sends the second high-level voltage signal thereto.

Claim 13

A drowsiness alarm system for a vehicle as set forth in claim 1, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy from various vehicle operating conditions except a vehicle steering condition; and (67) (b) a second AND gate, one of the two input terminals is connected to said quick steering detection (13) circuit, the other input terminal of which is connected to (101) said vehicle condition responsive circuit, and an output terminal of which is connected to said alarm unit for enabling the second pulse from said quick steering (13) detection circuit to pass therethrough to said alarm unit (10) (101) only when said vehicle condition responsive circuit sends the second high-level voltage signal thereto.

Claim 14

A drowsiness alarm system for a vehicle as set forth in claim 2, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy from various vehicle operating conditions except a vehicle steering condition; and (67) (b) a second AND gate, one of the two input terminals is connected to said steering angle detection circuit, the other input terminal of wich is connected to (101) said vehicle condition responsive circuit, and an output terminal of which is connected to said frequency of (18) steering detection circuit for enabling the first pulse from said steering angle detection circuit (2) to pass therethrough to said frequency of steering detection circuit (18) only when said vehicle codition responsive circuit sends the second high-level voltage signal thereto.

Claim 15

A drowsiness alarm system for a vehicle as set forth in claim 2, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy from various vehicle operating conditions except a vehicle steering condition; and (67) (b) a second AND gate, one of the two input terminals is connected to said frequency of steering (18) detection circuit, the other input terminal of which is (101) connected to said vehicle condition responsive circuit, and an output terminal of which is connected to said alarm unit (10) for enabling the third pulse from said frequency of (18) steering detection circuit to pass therethrough to said (10) alarm unit only.. when said vehicle condition responsive circuit sends the second high-level voltage signal thereto.

Claim 16

A drowsiness alarm system for a vehicle as set forth in claim 3, wherein the output terminals of both said quick steering and frequency of steering detection circuits (13,18) are connected to said alarm unit via a first OR gate and which is characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy from various vehicle operating conditions except a vehicle steering condition; and (b) a second AND gate (67), one of the two input terminals of which is connected to said steering angle (2) detection circuit, the other input terminal of which is (101) connected to said vehicle condition responsive circuit, and an output terminal of which is connected to the input terminals of both said quick steering and said frequency of (13,18) steering detection circuits for enabling the first pulse from said steering angle detection circuit to pass therethrough to both said quick steering and said frequency (13,18) of steering detection circuits only when said vehicle condition responsive circuit sends the second high-level .voltage signal thereto.

Claim 17

A drowsiness alarm system for a vehicle as set forth in claim 3, wherein the output terminals of both said quick steering and said frequency of steering detection (13,18) circuits are connected to said alarm unit via a first OR gate and which is characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonus state as to make the vehicle driver drowsy from. various vehicle operating conditions except a vehicle steering cndition; and (67) (b) a second AND gate, one of the two input terminals of which is connected to the output terminal of (40) said first OR gate, the other input terminal is connected (101) to said vehicle condition responsive circuit, and an output terminal of which is connected to said alarm unit for enabling both second and third pulses passed through said (40) first OR gate from said quick steering and said frequency (13,18) of steering detection circuits to pass therethrough to said alarm unit only when said vehicle condition responsive (101) circuit sends the second high-level voltage signal thereto.

Claim 18

A drowsiness alarm system for a vehicle as set forth in any one of claims 1 through 15, wherein said steering angle detection circuit is characterized by (3) (a) a positive peak detector, connected to said steering angle sensor, which holds and outputs the local maximum level of the varying output voltage from said steering angle sensor, decreasing the held maximum level by a reference voltage,corresponding to a predetermined change of angle, when reset; (4) (b) a negative peak detector, connected to said steering angle sensor, which holds and outputs the local minimum level of the varying output voltage from said steering angle sensor, increasing the held minimum level by the reference voltage,corresponding to the predetermined change of angle, when reset; (5) (c) a differential amplifier, connected to the output terminals of both said positive and said negative (3,4) peak detectors, which outputs a difference voltage signal according to the difference between output signals from (3,4) said positive and negative peak detectors; and (d) a first comparator (6) , connected to said differential amplifier (5), which compares the difference voltage signal with a predetermined voltage and generates the first pulse-when the difference voltage signal reaches the predetermined voltage V REF , the first pulse resetting said positive and negative peak detectors (3,4) .

Claim 19

A drowsiness alarm system for a vehicle as set forth in any one of claims 1, 3 through 5, 8 through 11, 14, and 15, wherein said quick steering detection circuit is characterized by (a) a first monostable multivibrator (8) which outputs a third high-level voltage signal for a predetermined period of time in response to the first pulse from said steering angle detection circuit (2); (b) a third AND gate (12) connected between said steering angle detection circuit (2) and the input terminal of said first monostable multivibrator (8) ; (c) a first inverter (11) connected between input terminal of said third AND gate (12) and the output terminal of said first monostable multivibrator (8) for outputting an inverted signal of the output signal of said first monostable multivibrator (8) to an input terminal of said third AND gate (12) ; (d) a first counter (9) , connected between said steering angle detection circuit (2) and alarm unit (10), which counts the number of inputted first pulses during the time when the third high-level voltage signal from said first monostable multivibrator is inputted thereto and outputs the second pulse when the counted number reaches the predetermined number.

Claim 20

A drowsiness alarm system for a vehicle as set forth in any one of claims 1, 3 through 5, 8 through 11, 14, and 15, wherein said quick steering detection circuit (13) is characterized by (a) a second monostable multivibrator (8'), .connected to said steering angle detection circuit, which outputs a fourth high-level voltage signal for a predetermined period of time whenever the first pulse from said steering angle detection circuit is inputted; (14) (b) an integrator, connected to said second monostable multivibrator, which integrates the fourth high-level voltage signal fed from said second monostable multivibrator; and (15) (c) a second comparator, connected to said (14) integrator for comparing the integrated voltage signal from (14) said integrator with a predetermined voltage and for outputting the second pulse when the integrated voltage exceeds a predetermined voltage level.

Claim 21

A drowsiness alarm system for a vehicle as set forth in any one of claims 2, 3, 6 through 9, 12 through 15, wherein said frequency of steering detection circuit (18) .is characterized by (20) (a) a first timer which generates a fourth pulse whenever a predetermined period of time has passed; (19) (b) a. second counter, connected to said steering angle detection circuit, which counts the number of the first pulses fed from said steering angle detection circuit, (1) and is reset by the fourth pulse fed from said (20) first timer, and which outputs the third pulse when the counted number reaches a predetermined number.

Claim 22

A drowsiness alarm system for a vehicle as set forth in any of claims 2, 3, 6 through 9, 12 through 15, wherein said frequency of steering detection circuit(18) is characterized by (a) a second timer (21), connected to said steering angle detection circuit (2), for outputting a fifth high-level voltage signal for a predetermined period of time whenever the first pulse from said steering angle detection circuit(2) is received; (23) (b) a first differentiator, connected to said (21) second timer, for differentiating the fifth high-level (21) voltage signal fed from said second timer and outputting a first differentiated pulse signal responsive to the rising edge of the fifth high-level voltage signal outputted from (21) said second timer; (22) (c) a second inverter, connected to said second (21) timer, which inverts the level of the output voltage signal .of said second timer; (21) (24) (d) a second differentiator (24) , connected to said second inverter (22), for differentiating the inverted voltage signal fed from said second inverter and outputting a second differential pulse signal responsive to the falling edge of the fifth high-level voltage signal outputted from said second timer (21); (e) a third timer (25) , connected to said first differentiator (23), which starts counting the time in response to the first differentiated pulse signal from said first differentiator (23) and outputs a fifth pulse whenever the counted time reachs a predetermined value, and which is reset by the second differentiated pulse signal from said second differentiator (24) ; (f) a second OR gate (26) , connected to said third timer (25) and said second differentiator (24); (g) a flip-flop (27), the set terminal of which is connected to said first differentiator (23) and reset terminal(R) is connected to said second OR gate (26) , and which is set by the first differentiated pulse signal from said first differentiator (23) to output a sixth high-level voltage signal from a Q output terminal thereof, and which is reset by the output signal of said second OR gate (26) ; (h) a fourth AND gate (28) connected to said flip-flop and to said steering angle detection circuit (2) ; (i) a third counter (30) , connected to said fourth AND gate (28) , which counts the number of the first pulses fed (2) from said steering angle detection circuit via said fourth (28) (27) AND gate passed while said flip-flop sends the sixth high- level voltage signal to said fourth AND gate, and which outputs the second pulse when the counted number of the first pulses reaches a predetermined number; and (29) (j) a third OR gate, connected to said second OR (26) (30) gate and an output terminal of said third counter, for sending the output signals from either said second OR gate (26) (30) or said third counter to a reset terminal of said third . (30) counter as a reset signal.

Claim 23

A drowsiness alarm system for a vehicle as set forth in any one of claims 10 through 15, wherein said vehicle condition responsive circuit (101) is characterized by (41-45) (a) a first circuit, responsive to the operation of a turn signal indicator light of the vehicle, which outputs a seventh high-level voltage signal when the driver turns on the turn signal indicator switch and until a predetermined period of time after the driver turns off the turn signal indicator switch; (46-50) (b) a second circuit, responsive to the depression of a brake pedal of the vehicle, which outputs an eighth high-level voltage signal when the driver depresses the brake pedal and until a predetermined period of time after the driver releases from the brake pedal; (51-55) (c) a third circuit, responsive to the operation of .an accelerator pedal of the vehicle, which . outputs a ninth high-level voltage signal when the driver nearly fully depresses or releases the accelerator pedal at a full stroke except within a predetermined range of stroke with respect to-either of maximum and minimum strokes of the accelerator pedal and until a predetermined period of time after when the driver operates the accelerator pedal at the predetermined range of stroke; (16, 56-59) (d) a fourth circuit, responsive to a vehicle speed, which outputs a tenth high-level voltage signal when the vehicle speed is below a predetermined value and until a predetermined period of time after the vehicle speed exceeds the predetermined value; (60-64) (e) a . fifth circuit, responsive to the operation of a gear selector lever, which outputs an eleventh high-level voltage signal when the gear selector lever is placed at any position except top and overdrive positions and until a predetermined period of time after the gear selector lever is shifted to either of the top and overdrive positions from any other position; and . (65,66) (f) a NOR gate, connected to said first, second, (41-55, 16,56-64) third, fourth, and fifth circuits, wich sends the inverted voltage signal of the second high-level voltage signal to (67) said second AND gate when any of the high-level voltage signals from said first, second, third, fourth, and fifth circuits are received.

Claim 24

. A drowsiness alarm system for a vehicle as set forth in claim 21, wherein said first circuit (41-45) is character- i zed by (a) a turn signal indicator switch which outputs a high-level voltage signal when either of the turn signal indicator-lights is turned on; (42) (b) a third inverter, connected to said turn signal indicator switch, which inverts the output signal level of said turn signal indicator switch; (c) a third differentiator, connected to said third inverter, which differentiates the output inverted signal of said third inverter (42) so as to detect the falling edge of the high-level voltage signal when the turn signal indicator light is turned off; (d) a fourth timer, connected to said third differentiator, which outputs a high-level voltage signal 44a)for a predetermined period of time upon receiving the differentiated signal of said third differentiator (43) responsive to the falling edge of the high-level voltage signal of said turn signal indicator switch (41); and (e) a fourth OR gate (45), connected to said turn signal indicator switch (41) and said fourth timer (44), which outputs the seventh high-level voltage signal in response to the high-level voltage signals from both said turn signal indicator switch (41) and said fourth timer (44).

Claim 25

A drowsiness alarm system for a vehicle as set forth in claim 21, wherein said second circuit (46-50) is characterized by (a) a brake pedal operation sensor (46) which outputs a high-level voltage signal when the brake pedal is depressed; (47) (b) a fourth inverter, connected to said brake (46) pedal operation-sensor, which inverts the output signal (46) level from said brake pedal operation sensor; (c) a fourth differentiator, connected to said (47) fourth inverter, which differentiates the output signal of (47) said fourth inverter so as to detect the falling edge of the high-level voltage signal of said brake pedal operation (46) sensor when the brake pedal is depressed; (49) (d) a fifth timer, connected to said fourth (48) differentiator, which outputs a high-level voltage signal for a predetermined period of time upon receiving the differentiated signal of said fourth differentiator (48) responsive to the falling edge of the high-level voltage (46) signal of said brake pedal operation sensor; and (e) a fifth OR gate, connected to said brake pedal operation sensor and said fifth timer, which outputs the eighth high-level voltage signal in response to the high-level voltage signals from said brake pedal operation (46) (49) sensor and said fifth timer.

Claim 26

A drowsiness alarm system for a vehicle as set forth in claim 21, wherein said third circuit (51-55) is characterized by (a) an acceleration/deceleration sensor, which outputs a high-level voltage signal when the accelerator pedal of the vehicle is depressed or released to within a predetermined range of stroke with respect to the extreme strokes of the accelerator pedal; (52) (b) a sixth timer, connected to said (51) acceleration/deceleration sensor, which outputs a high-level voltage signal for a predetermined period of time after the high-level voltage signal is inputted thereto (51) from said acceleration/deceleration sensor; (53) (c) a fifth inverter, connected to said third (52) timer, which inverts the output signal level from said sixth timer; (54) (d) a fifth AND gate, connected to said (51) acceleration/deceleration sensor and to said fifth (53) inverter, which takes the logical AND between the output signals from both said acceleration/deceleration sensor ( 51 ) and said fifth inverter, and outputs a high-level voltage signal when the predetermined period of time has passed after the accelerator pedal is depressed or released to within the predetermined range of stroke; and (55) (e) a sixth inverter, connected to said fifth (54) AND gate, which inverts the output signal of said fifth AND gate so as to output the ninth high-level voltage signal (54) when said fifth AND gate sends a low-level voltage signal thereto.

Claim 27

A drowsiness alarm system for a vehicle as set forth in claim 21, wherein said fourth circuit (16,56-59) is cha- racterized by(a) a vehicle speed sensor which outputs a high-level voltage signal when the vehicle speed exceeds a predetermined value; (56) .(b) a seventh timer, connected to said vehicle (16) speed sensor, which outputs a high-level voltage signal for a predetermined period of time in response to the high-(16) level voltage signal from said vehicle speed sensor; (57) (c) a seventh inverter, connected to said (56) seventh timer, which inverts the output signal level of (56) said seventh timer; (58) (d) a sixth AND gate, connected.to said vehicle (57) speed sensor and to said seventh inverter, which takes the logical AND between the output signals of both said vehicle (16) (57) speed sensor and said seventh inverter and outputs a high-level voltage signal indicating that the predetermined period of time has passed since the vehicle speed exceeded the predetermined value; and (59) (e) an eighth inverter, connected to said sixth (58) AND gate, which inverts the output signal level of said (58) sixth AND gate and outputs the tenth high-level voltage signal when the output signal of said sixth AND gate is at a low level.

Claim 28

A drowsiness alarm system for a vehicle as set forth in claim 21, wherein said fifth circuit (60-64) is character- ized by (a) a gear selector lever position sensor which outputs a high-level voltage signal when the gear selector lever is in either of the top or overdrive positions; (61) (b) an eighth timer, connected to said gear (60) selector lever position sensor, which outputs a high-level voltage signal for a predetermined period of time in response to the high-level voltage signal from said gear (60) selector lever position sensor; (c) a ninth inverter, connected to said third timer, which inverts the voltage level of the output signal of said third timer; (63) (d) a seventh AND gate, connected to said gear selector lever position sensor and to said eighth inverter, which takes the logical AND between the output signals of (60) both said gear selector lever position sensor and said (62) eighth inverter and outputs a high-level voltage signal representing the predetermined period of time after the gear selector lever is shifted to either of the top and overtop positions; and (64) (e) a tenth inverter, connected to said seventh (63) AND gate, which inverts the voltage level of the output (63) signal from said seventh AND gate and outputs the eleventh high-level voltage signal when the voltage of the output (63) signal from said seventh AND gate is at a low level.

Claim 29

A drowsiness alarm system for a vehicle as set forth in any one of claims 2, 6, 7, 12, and 13, wherein said alarm unit (10) is characterized by (37) (a) a first alarm device, connected to said (18) frequency of steeri.ng detection circuit, wh.ich gives a gentle alarm indication to the driver in response to the third pulse fed from said frequency of steering detection circuit; (31) (b) a ninth timer, connected to said frequency (18) of steering detection circuit, which outputs a high-level voltage signal for a predetermined period of time in response to the third pulse fed from said frequency of (18) steering detection circuit; (32) (c) an eleventh inverter, connected to said (31) ninth timer, which outputs an inverted voltage signal when .the high-level voltage signal from said ninth timer is inputted; (d) a fifth differentiator, (33) connected to said tenth inverter (32), which differentiates the inverted voltage signal of said tenth inverter (32) to output a differentiated signal responsive to the falling edge of the high-level voltage signal outputted from said ninth timer (31) ; (e) an eighth AND gate (34) , connected to said frequency of steering detection circuit (18) and to said ninth timer (31) , which enables the third pulse from said frequency of steering detection circuit (18) to pass therethrough while the high-level voltage signal from said ninth timer (31) is received; (f) a fourth counter (35) , connected to said eighth AND gate (34) , which counts the number of the third pulses passed via said eighth AND gate (34) and outputs a fifth pulse (35a) when the counted number of the th.ird pulses reaches a .predetermined number; (36 ) (g) a sixth OR gate, connected to said fifth differentiator and to the output terminal of said fourth counter, which sends the logical OR signal of the (33) differentiated signal from said fifth differentiator and the fifth pulse from said fourth counter into said fourth (35) counter for resetting said fourth counter; and (38) (h) a second alarm device, connected to said (35) fourth counter, which gives an intense alarm indication to (35a) the vehicle driver in response to the fifth.pulse from said (35) fourth counter.

Claim 30

A drowsiness alarm system for a vehicle as set forth in claim 3, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting that the vehicle travels in such a monotonous state as to make the vehicle driver drowsy; (b) a second AND gate, (67) one of the two input terminals of which is connected to said steering angle detection circuit, the other input terminal of which is (101) connected to said vehicle condition responsive circuit, and an output terminal of which is connected to both input terminals of said quick steering and frequency of steering (13,18) detection circuits for enabling the first pulse from said steering angle detection circuit (2) from passing therethrough to both said quick steering and frequency of steering (13,18) .detection circuits only when said vehicle condition responsive circuit sends the second high-level voltage signal thereto, and wherein said alarm unit (10) os further charac- terized by (c) a first alarm device, connected to said frequency of steering detection circuit, which gives a gentle alarm indication to the driver; (31) (d) a ninth timer, connected to said frequency (18) of steering detection circuit, which outputs a high-level voltage signal for a predetermined period of time in response to the third pulse fed from said frequency of steering detection circuit; (e) a eighth AND gate, connected to said frequency of steering detection circuit(18) and to said ninth timer (31) , which enables the third pulse from said frequency of steering detection circuit to pass therethrough while the high-level voltage signal from said ninth timer (31) is received; (f) a fourth counter (35) , connected to said eighth AND gate (34) , which counts the number of the third pulses passed via said eighth AND gate (34) and outputs a fifth pulse(35a) when the counted number of the third pulses reaches a predetermined number, and which is reset by the fifth pulse outputted therefrom; (g) a seventh OR gate (39) , connected to said fourth counter (35) and said quick steering detection circuit (13) , which takes the logical OR between the fifth pulse (35a) of said fourth counter (35) and the second pulse of said quick steering detection circuit; and (38) (h) a second alarm device, connected to said seventh OR gate, wich gives an intense alarm to the vehicle driver in response to the output signal of said seventh OR (39) gate.

Claim 31

A drowsiness alarm system for a vehicle as set forth in claim 3, characterized by (a) a vehicle condition responsive circuit (101) which generates a second high-level voltage signal only when detecting tha the vehicle travels in such a monotonous state as to make the vehicle driver drowsy; (b) a ninth AND gate, connected to said frequency of steering detection circuit and to said vehicle (101) condition responsive circuit, which enables the third pulse (18) from said frequency of steering detection circuit from passing therethrough only when the second high-level signal (101) from said vehicle condition responsive circuit is received; and (c) a tenth AND gate, connected to said quick (13) steering detection circuit and to said vehicle condition (101) responsive circuit, which enables the second pulse from said quick steering detection circuit (13) to pass therethrough only when the second high-level signal from said vehicle condition responsive circuit is received, and wherein said alarm unit (10) is further characterized (37) by (d) a first alarm device, connected to said ninth AND gate which gives a gentle alarm to the vehicle driver in response to a high-level voltage signal therefrom; (31) (e) a ninth timer, connected to said ninth AND (67') gate, which outputs a high-level voltage signal for a predetermined period of time in response to the third pulse (19a,30a) (18) fed from said frequency of steering detection circuit via said ninth AND gate; (f) a eighth AND gate, connected to said ninth AND gate and to said ninth timer, which enables the third pulse from said frequency of steering detection circuit via said ninth AND gate to pass therethrough while the high- level voltage signal from said ninth timer is received; (35) (g) a fourth counter, connected to said eighth (34) AND gate, which counts the number of the third pulses passed via said eighth AND gate and outputs a fifth pulse (35a) when the counted number of the third pulses reaches a predetermined number, and which is reset by the fifth pulse outputted therefrom; (39) (h) a seventh OR gate, connected to said fourth (35) (67") counter and said tenth AND gate, which takes the logical OR (35) between the fifth pulse of said fourth counter and the (13) second pulse of said quick steering detection circuit via (67") ; said tenth AND gate; and (38) (i) a second alarm device, connected to said (39) seventh OR gate, which gives an intense alarm to the vehicle driver in response to the output signal of said (39) seventh OR gate.