JPH0147174B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heart rate monitor that measures a person's pulse.
Especially regarding heart rate monitors mounted on cars. When driving a vehicle, if the driver's health is not good, there is a high possibility of causing an accident.
For example, if you continue to drive for a long time without taking a break, fatigue accumulates, your health condition worsens, and your ability to concentrate decreases. Heart rate is one barometer that can tell us about a person's health condition. Recently, small portable heart rate monitors have been sold as devices for measuring heart rate. Although this type of heart rate monitor can be carried anywhere, its measurement accuracy is low. For example, even if a driver of a car brings such a heart rate monitor into the vehicle in order to know his/her own health condition, the heart rate measurement must be carried out while the vehicle is stopped. Failure to do so is dangerous. However, for example, on a highway, it is not possible to stop the vehicle while driving for a long time, so heart rate measurement cannot be performed during that time. The need for heart rate measurement in vehicles is higher on expressways than on general roads, so if heart rate measurement cannot be performed on expressways, there is little value as an on-vehicle heart rate meter. The present invention can detect the driver's physical and mental state to identify whether there is a danger in driving, and can prevent the occurrence of drowsy driving by notifying the driver of the danger. The purpose is to provide an on-vehicle heart rate monitor. In order to achieve the above object, in the present invention,
A heartbeat detecting means including a light emitting means and a light receiving means, which are arranged close to each other on a wheel, a spoke of a steering wheel, or an operation board on the steering wheel; a light emitting energizing means for energizing the light emitting means to emit light; instructing the energizing means to emit light, measuring a plurality of cycles of each of the heartbeat signals obtained from the light receiving means, and determining the degree of dispersion based on the values of the plurality of heartbeat cycles obtained by the measurement. control means for detecting the indicated value and identifying the presence or absence of an abnormality according to the magnitude of the value indicating the degree of variation; and when the control means identifies the presence of an abnormality, a warning is issued by at least one of display and sound output. An abnormality warning means shall be provided. That is, for example, if light is emitted from the light-emitting means with the optical axis of the light-emitting means and the light-receiving surface of the light-receiving means facing the same part of a person's finger, the amount of blood passing through the blood vessels of the person's finger will decrease.
Since the amount of reflected light reaching the light receiving means changes in accordance with changes in synchronization with the heartbeat, a heartbeat signal can be obtained by detecting the change. According to this, since the detection section is located on or near the steering wheel, the driver can measure the heartbeat while driving while holding the steering wheel. For example, when a driver starts dozing off from a normal driving condition, the variation in heartbeat cycles tends to increase rapidly. In other words, changes in the length of the heartbeat cycle become large. According to the present invention, the presence or absence of an abnormality is identified by examining the magnitude of the value according to the degree of variation in the heartbeat cycle, so that even a driver's dozing can be detected as an abnormality. Furthermore, if an abnormality such as falling asleep is detected, a warning of the abnormality is given, so that the driver is notified of the danger and traffic accidents can be prevented from occurring. In the examples described later, a large number of heartbeat cycles are repeatedly and continuously sampled, differences between the cycles of adjacent heartbeats are determined, and the maximum value of the differences is determined as a value indicating the degree of variation in heartbeat cycles. It is detected as. Of course, the value indicating the degree of dispersion can also be obtained by another method. For example, in a common method, if there are N sampling data x ₁ , x ₂ , x ₃ , ...xn, the average value x ₀ is calculated, and each sampling data x ₁ ,
Find the difference between x ₂ , x ₃ , ... xn and the average value x ₀ ,
By calculating the average value of the differences, a value indicating the degree of dispersion (called variance in mathematics) can be obtained. In addition, in the embodiment described later, the light emitting means and the light receiving means are fixed to a key supported by an elastic member such as a spring, so that when the key is pressed, the contact state between the finger and the light emitting means and the light receiving means is automatically brought to the proper state. It is designed to be. According to this, the contact state between the finger and the light emitting means and the light receiving means can be maintained in a proper state without any special adjustment. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1a shows the vicinity of a steering wheel of a type of automobile in which the present invention is implemented. Referring to FIG. 1a, 1 is a steering wheel, 2 and 3 are spokes that support the steering wheel 1, and 4 is a central pad equipped with the main body of an on-vehicle heart rate monitor. The two spokes 2 and 3 are provided with detectors 5 and 6 and switches 7 and 8, respectively. The center pad 4 has switches 9, 10 and light emitting diode indicators 11, 1.
A seven segment light emitting diode indicator 14 with 2, 13 and 3 digits is provided. FIG. 1b shows a cross section taken along line Ib-Ib in FIG. 1a. Referring to FIG. 1b, the slightly inclined surface of the detector 5 is provided with a light emitting diode (ie, light emitting means) PD1 and a phototransistor (ie, light receiving means) PT1. light emitting diode PD
1 and the emitter of the phototransistor PT1 are connected to the steering wheel 1 and the core (grounded metal) 15 of the spokes 2 and 3, and the anode of the light emitting diode PD1 and the collector of the phototransistor PT1 are connected to lead wires, respectively. It is connected to the main body of the on-board heart rate monitor via 16 and 17. The switch 7 is placed close to the detector 5 so that the detector 5 and the switch 7 can be touched simultaneously with one finger. Note that the detector 6 placed on the spoke 3 has a
Light emitting diode PD2 and phototransistor PT2
It's equipped. FIG. 2 shows a schematic configuration of the electric circuit of the on-vehicle heart rate monitor shown in FIG. 1a. The configuration will be explained with reference to FIG. In this example, an Intel single-chip microcomputer (8048) CPU is used.
is used. The anodes of the light emitting diodes PD1 and PD2 of the detectors 5 and 6 are connected to the output of the oscillator OSC via a resistor. The oscillator OSC is a 1KHz square wave oscillator, and the oscillation is controlled by the microcomputer CPU.
The output ends (i.e. collectors) of phototransistors PT1 and PT2 are connected to relays RL1 and RL2.
It is connected to the amplifier AM1 through the contacts of .
Relays RL1 and RL2 are controlled by transistors Q1 and Q2, respectively, connected to the output ports of the microcomputer CPU. amplifier
The output end of AM1 is connected to filter FL1. Filter FL1 is a low-pass filter that removes frequency components of 1 KHz or higher, that is, a noise filter. The output end of filter FL1 is the detector DT.
1, and the output terminal of the detector DT1 is
Connected to amplifier AM2 and comparator CP1. The aforementioned light emitting diode indicator 13 is connected to the output terminal of the amplifier AM2. Comparator CP1
The output terminal of is connected to the external interrupt input terminal INT of the microcomputer CPU. The light emitting diode indicators 11 and 12 are controlled by transistors Q3 and Q4, respectively, connected to the output ports of the microcomputer CPU. Switches 9 and 10 on the central pad 4 are connected to the input ports of the CPU via inverters IN1 and IN2, respectively. VR1 and VR
2 are variable resistors for setting the upper and lower limits of the heart rate, respectively. The movable pieces of variable resistors VR1 and VR2 are connected to input terminals 0 and 1 of an A/D converter ADC, respectively.
A conversion data output terminal and an input channel selection input terminal of the A/D converter ADC are connected to a microcomputer CPU. spokes 2,3
The upper switches 7 and 8 are each connected to an input port of the microcomputer CPU.
A buzzer BZ, an audio output device VGU, and a display circuit DSP are connected to other output ports of the CPU. The display circuit DSP is a 4-bit latch LA1,
LA2 and LA3, multiplexer MPX, decoder DEC, counter CO1, digit driver DR1,
It is composed of a segment driver DR2 and a 3-digit 7-segment light emitting diode display 14. Microcomputer CPU and display circuit DSP
are connected by four lines for passing BCD (Binary Coded Decimal) signals and three lines for selecting digits. Latch LA1, LA2
and LA3 output signal is multiplexer MPX
and one of them is applied to the counter CO
1 output signal is selected and applied to the decoder DEC. The decoder DEC generates a 7 segment signal from the BCD signal. The output signal of the decoder DEC is applied to the segment driver DR2. The segment driver DR2 is composed of seven sets of transistors, and switches the cathode of each segment of the light emitting diode display 14 to ground or open. A common anode of each digit of the light emitting diode display 14 is connected to a digit driver DR1. The digit driver DR1 is composed of three sets of transistors, etc., and connects the common anode of any digit of the display 14 to a predetermined potential Vcc in response to a signal from the counter CO1. counter CO
1 is a ternary counter that counts the output signal of the oscillator OSC. That is, depending on the three states of counter CO1, voltage Vcc is applied to the anode of any digit of display 14, and one of the output signals (display data) of latches LA1, LA2, and LA3 is selected. decoder DEC
A predetermined segment is grounded according to the output of the decoder DEC, and the segment grounded by the segment driver DR2 of the digit selected by the digit driver DR1 emits light. The general operation of heart rate measurement will be explained. First, the measurement start switch 10 is operated, and as shown in FIG. 1b, the subject's finger is pressed against the detector 5 (or 6) and the switch 7 (or 8) is pressed. Now the signal from phototransistor PT1 or PT2 will be transmitted to the relay.
It is applied to the amplifier AM1 via the RL1 or RL2 contact. Here, light emitting diode PD1 and
A 1KHz signal from the OSC is applied to PD2, and PD1 or PD2 intermittently emits light to the finger at a frequency of 1KHz. Inside the finger, the amount of blood flowing through the blood vessels changes depending on the pulse. and,
When the amount of blood is large, the light from PD1 or PD2 is reflected by the blood and reaches the phototransistor PT1 or PT2. When the amount of blood is small, there is less light reflection, so the light that reaches the phototransistor PT1 (or PT2) is is weak. That is, a 1KHz signal whose amplitude is modulated in accordance with the pulsation is generated at the output terminal of the phototransistor PT1. This signal is
The signal is amplified by the amplifier AM1, and noise is removed by the filter FL1. The detector DT1 extracts the envelope signal component of the modulated wave, that is, the signal corresponding to the pulsation. This signal energizes the light emitting diode indicator 13 via amplifier AM2. Further, a binary signal corresponding to the beat is generated at the output of the comparator CP1, and this is applied to the external interrupt input terminal INT of the CPU. The microcomputer CPU measures the heart rate by counting the number of external interrupts within a predetermined period of time. Note that the light emitting diode indicator 13 indicates the state of contact between the detector 5 (or 6) and the finger. Figure 3 shows the microcomputer in Figure 2.
An overview of CPU operation is shown. The operation of each step will be explained with reference to FIG. Set the S1 circuit to its initial state. That is,
Open the contacts of relays RL1 and RL2,
Latches LA1, LA2 and LA3 are set to ``0'' to de-energize buzzer BZ and de-energize light emitting diode indicators 11 and 12. Check S2 switch 10 and wait for it to turn on. The switch 10 is a start switch that instructs the start of heart rate measurement. S3 Set the input channels of the A/D converter ADC to 0 and 1, and set the heart rate upper limit data and heart rate lower limit data obtained by A/D converting the voltages from variable resistors VR1 and VR2 to registers MH and ML, respectively. do. Note that the variable resistors VR1 and VR2 are set in advance to predetermined states by the driver. S4 Wait for switch 7 or 8 to be pressed. When switch 7 is pressed, the process advances to step 5, and when switch 8 is pressed, the process advances to step S6. S5 Switch 7 is pressed, so a high level H signal is applied to transistor Q1, and relay RL
Set contact 1 to "closed". In addition, the left light emitting diode indicator 11 is turned on to confirm the start of heart rate measurement of the left hand. S6 Since switch 8 was pressed, a high level H signal is applied to transistor Q2, and relay RL
Set contact 1 to "closed". In addition, the right light emitting diode indicator 12 is turned on to confirm the start of heart rate measurement of the right hand. When the process of step S5 or S6 is completed, an analog signal corresponding to the pulsation is generated at the output terminal of the wave detector DT1. The level of this analog signal changes greatly depending on the contact state between the finger and the detector 5 (or 6), so the subject, that is, the driver,
The finger position and finger force are adjusted so that the blinking brightness of the light emitting diode indicator 13 is in a predetermined state. S7 Wait for the specified time To. The time To is the time required for the signal level of the output of the detector DT1 to stabilize after the switch 7 or 8 is pressed. S8 Set variable S to 5. This means that heart rate measurements are performed five times in a row. S9 Starts the microcomputer CPU's internal timer and enables internal timer interrupts. S10 Enables external interrupts, that is, interrupts caused by signals applied to the INT terminal. S11 Checks whether switch 9 is pressed. Switch 9 is a cancel switch for stopping heart rate measurement midway. S12 Since cancel switch 9 has been pressed, interrupts are disabled, the timer and memory of variables N and M are cleared, the display and instructions are reset, and relays RL1 and RL2 are set to "open".
Return to step S2. S13 Compare variable N with time constant T1. T1 corresponds to the time of one heartbeat measurement. The variable N is cleared to 0 when heart rate measurement is started, and is incremented every time there is an internal timer interrupt in step S30. S14 Calculate heart rate from variable M and store the result in register Mx. The variable M is cleared to 0 when starting the heart rate measurement and the step
It is incremented by one each time there is an external interrupt at the INT end of S40. S15 Read the contents of register Mx that stores the heart rate and latch it one digit at a time LA1, LA2
and output to LA3. The heart rate as a measurement result is now displayed on the 7-segment display 14 as a 3-digit value. S16 The contents of register Mx are compared with the upper limit setting value of register MH and the lower limit setting value of register ML. S17 Since the heart rate is outside the preset range, buzzer BZ is activated for 1 second to issue an alarm. S18 Controls the voice output device VGU and announces "Take a break." S19 Disable interrupts, internal timer, memory N
and clear the contents of M to 0. S20 Decrement variable S by one. S21 Check whether the content of variable S is 0. If it is not 0, the process returns to step S9 and starts heart rate measurement again. S22 Deenergizes the light emitting diode indicators 11 and 12 and opens the contacts of relays RL1 and RL2.
and return to step S2. S30 Increment variable N. When this process is finished, the process immediately returns to the original process. S40 Increment variable M. When this process is finished, the process immediately returns to the original process. Next, another embodiment will be described. In Figure 4,
The configuration near the detector 5 is shown. In this example, the light emitting diode of detector 5 (and 6)
PD1 and phototransistor PT1 are fixed to a sliding key KY supported by a compression coil spring SP. The strength of the spring SP is determined by the sliding key KY
is set so that when the finger is pressed down by the amount that it protrudes from the spoke 2, the state of contact between the finger and the light emitting diode PD1 and the phototransistor PT1 is favorable for detecting a pulsation. That is, in this embodiment, when the sliding key KY is pressed down, the contact state between the finger and the key is automatically set to a state convenient for heart rate measurement without adjusting the force of the finger. Therefore, in this example,
The light emitting diode indicator 13 that indicates the contact state between the finger and the detectors 5 and 6 and the circuit that drives it, which were used in the previous embodiment, have been eliminated. FIG. 5 shows the configuration of the electric circuit of the on-vehicle heart rate monitor shown in FIG. 4. Referring to FIG. 5, this embodiment eliminates the light emitting diode indicator 13 and amplifier AM2 of the previous embodiment. Further, in this embodiment, the variable resistors VR1 and VR
2 and A/D converter ADC have been abolished,
Instead, 12 key switches K0, K1,
K2, K3, K4, K5, K6, K7, K8, K
9. Equipped with KH and KL. These key switches are used to set upper and lower heart rate limits that determine whether or not an alarm is issued. The other configurations are the same as in the previous embodiment. 6a and 6b show the operation of the microcomputer CPU of FIG. 5. First, the operation will be explained with reference to FIG. 6a. What is different in FIG. 6a from FIG. 3 is step S50 and step S50.
The only difference is that S100 has been added. step
For S50, key switches K0 to K9, KH and
Check if KL has been manipulated. This is done by setting one of the output ports P4, P5, and P6 to a low level L, setting the other port to a high level H, and changing the port to be set to a low level in a predetermined period.In the meantime, input ports P0 to P3 Read the status of
If even one of these input ports is at a low level L, it is determined that there is a key input. step
S100 is a subroutine for setting the upper and lower limits of heart rate according to key operations. The detailed operation of step S100 is shown in FIG. 6b.
Each step will be explained with reference to FIG. 6b. S51 Check whether the pressed key switch is KH. S52 Since key switch KH was pressed, enter the upper limit value input mode. First, the variable N is set to 3, which corresponds to the number of input digits. S53 Waits for the next key switch to be pressed. S54 Check whether the pressed key switch is KH. S55 Check whether the pressed key switch is KL. S56 Stores the one-digit numerical value associated with the pressed key switch in the register RH (N) corresponding to variable N. S57 1 associated with the pressed key switch
The numerical value of the digit is displayed on the light emitting diode display 14. S58 Decrement variable N once. S59 Check whether the content of variable N is 0.
The upper limit value input mode operation from step S53 is performed until N becomes 0. S60 Check whether the pressed key switch is KL. S61 Since key switch KL was pressed, enter heart rate lower limit input mode. First, the variable N is set to 3, which corresponds to the number of input digits. S62 Waits for the next key switch operation. S63 Check whether the pressed key switch is KH. S64 Check whether the pressed key switch is KL. S64 Store the one-digit numerical value associated with the pressed key in register RL (N) corresponding to variable N. S66 Display the numerical value associated with the pressed key switch on the light emitting diode display 14. S67 Decrement variable N once. S68 Check whether the content of variable N is 0.
The lower limit value input mode operation from step S62 continues until N becomes 0. In the above embodiment, switches for instructing the start of measurement are provided near the detectors 5 and 6, but these switches may also be provided in the central pad 4. Also, for example, relays RL1 and RL2 are turned on at predetermined intervals, and the level of the signals from phototransistors PT1 and PT2 is checked each time.
Switches 7 and 8 may be omitted if the left or right detector starts heart rate measurement when the level indicates that the sensor is touching or 6. By the way, the period of each pulsation changes over a short period of time. For example, as shown in FIG. 6, the cycle at a certain point in time is L1, and the next cycle changes to L2. The degree of this periodic change, that is, the variation, is closely related to a person's level of tension. Table 1 below outlines the relationship between the general average value L of the heartbeat cycle and the variation ΔL of the heartbeat cycle, and the physical and mental state of a person.

[Table] Generally, when driving a vehicle, one is physically relaxed and mentally tense. However, when the driver falls asleep while driving due to fatigue or the like, the mental tension disappears and the heart rate returns to the state during sleep. In other words, referring to Table 1, if you start falling asleep while driving a vehicle,
The dispersion of the heartbeat cycle increases rapidly. Therefore, in the next embodiment, a means for preventing drowsy driving is added by monitoring changes in variations in the heartbeat cycle. FIG. 8 shows an electrical circuit of another embodiment of the invention. The configuration will be explained with reference to FIG.
The configuration of this circuit is variable resistor VR1 and VR
The circuit is the same as the circuit shown in FIG. 2 above, except that the connection at point 2 is changed. In this embodiment, variable resistor VR1 is used to set the upper limit of heart rate, and VR2 is used to set the upper limit of heart rate variation. Figure 9 shows the microcomputer in Figure 8.
The operation of the CPU is shown in FIG. 10, which shows the signal applied to the external interrupt input terminal INT of the CPU and the timing of the operation of the CPU. The operation of each step in FIG. 9 will be explained with reference to FIGS. 9 and 10. Set the S1 circuit to its initial state. That is,
Open the contacts of relays RL1 and RL2,
Latches LA1, LA2 and LA3 are set to ``0'' to de-energize buzzer BZ and de-energize light emitting diode indicators 11 and 12. Check S2 switch 10 and wait for it to turn on. The switch 10 is a start switch that instructs the start of heart rate measurement. S3' The input channels of the A/D converter ADC are set to 0 and 1, and the voltages from the variable resistors VR1 and VR2 are A/D converted, and the upper limit data of the heart rate and the upper limit data of the variation of the heartbeat cycle are registers MH and VH respectively
Set to . S4 Wait for switch 7 or 8 to be pressed. When switch 7 is pressed, the process advances to step 5, and when switch 8 is pressed, the process advances to step S6. S5 Switch 7 is pressed, so a high level H signal is applied to transistor Q1, and relay RL
Set contact 1 to "closed". In addition, the left light emitting diode indicator 11 is turned on to confirm the start of heart rate measurement of the left hand. S6 Since switch 8 was pressed, a high level H signal is applied to transistor Q2, and relay RL
Set contact 1 to "closed". In addition, the right light emitting diode indicator 12 is turned on to confirm the start of heart rate measurement of the right hand. When the process of step S5 or S6 is completed, an analog signal corresponding to the pulsation is generated at the output terminal of the wave detector DT1. The level of this analog signal changes greatly depending on the contact state between the finger and the detector 5 (or 6), so the subject, that is, the driver,
The finger position and finger force are adjusted so that the blinking brightness of the light emitting diode indicator 13 is in a predetermined state. S7 Wait for the specified time To. The time To is the time required for the signal level of the output of the detector DT1 to stabilize after the switch 7 or 8 is pressed. S8 Set variable S to 5. This means that heart rate measurements are performed five times in a row. S9 Starts the microcomputer CPU's internal timer and enables internal timer interrupts. S10 Enables external interrupts, that is, interrupts caused by signals applied to the INT terminal. S11 Checks whether switch 9 is pressed. Switch 9 is a cancel switch for stopping heart rate measurement midway. S12' Since cancel switch 9 was pressed, interrupts are disabled and the timer, variables N, MV, Vd,
Clears No, Mn and Mo memories, resets displays and instructions, relays RL1 and
Set RL2 to "open" and return to step S2. S13 Compare variable N with time constant T1. T1 corresponds to the time of one heartbeat measurement. The variable N is cleared to 0 when heart rate measurement is started, and is incremented every time there is an internal timer interrupt in step S30. S14 Calculate heart rate from variable M and store the result in register Mx. The variable M is cleared to 0 when starting the heart rate measurement and the step
It is incremented by one each time there is an external interrupt at the INT end of S40. S15 Read the contents of register Mx that stores the heart rate and latch it one digit at a time LA1, LA2
and output to LA3. The heart rate as a measurement result is now displayed on the 7-segment display 14 as a 3-digit value. S16' Compare the contents of register Mx with the upper limit setting value of register MH. S23 The contents of register V are compared with the heartbeat cycle variation upper limit setting value of register Vd. Register V
As will be explained in detail later, the maximum value of the variation in the heartbeat cycle from when the timer is started until the period T1 has elapsed is stored. S17 Since the heart rate is outside the preset range, buzzer BZ is activated for 1 second to issue an alarm. S18 Since the heart rate is higher than the value set in VR1 and the variation in the heartbeat cycle is higher than the value set in VR2, it is determined that the driver is drowsy while driving, and the voice output device VGU is controlled to say "take a break". Do it,” he announced. S19' Disables interrupts and clears the contents of the internal timer and memories N, M, V, Vd, No, Mn and Mo to 0. S20 Decrement variable S by one. S21 Check whether the content of variable S is 0. If it is not 0, the process returns to step S9 and starts heart rate measurement again. S22 Deenergizes the light emitting diode indicators 11 and 12 and opens the contacts of relays RL1 and RL2.
and return to step S2. S30 Increment variable N. When this process is finished, the process immediately returns to the original process. When the input terminal INT of the CPU becomes low level L,
An external interrupt is generated and entry is made to step S40a. S40a Check the contents of register M. At the first external interrupt, the contents of M are set to 0, and each time an external interrupt occurs, the contents of M are incremented at step S40j. S40b Set the contents of register V to 0 and store the contents of register N at that time in register No. This process is performed when the contents of register M are 0 and 1, that is, at the time of the first external interrupt and the second external interrupt. S40c Check whether the contents of register M is 1. S40d Since the second external interrupt is being processed, the value N-No is stored in register Mn. S40e After storing the contents of register Mn in register Mo, store the value of N-No in register Mn. S40f Store the contents of register N in register No. S40g Store the value of Mn−Mo in register Vd. Before starting this process, register Mo has the following information:
The number of internal timer interrupts that have occurred between the time when the external interrupt occurred before the previous one and the time when the previous external interrupt has occurred, that is, the previous heartbeat cycle, is stored, and the register Mn stores the number of internal timer interrupts that have occurred from the time when the external interrupt occurred before the previous time until the time when the previous external interrupt occurred, and the register Mn stores the number of internal timer interrupts that have occurred from the time when the external interrupt occurred before the previous time until the time when the previous external interrupt occurred. The number of internal timer interrupts that have occurred, ie, the current heartbeat cycle, is stored. Therefore, the difference between the previous heartbeat cycle and the current heartbeat cycle, that is, the change (variation) in the heartbeat cycle is stored in the register Vd. S40h Compare the contents of register Vd and register V. S40i Since the current heartbeat cycle change is the maximum value up to that point, store the value of register Vd in register V. S40j Increment the contents of register M. In the embodiment shown in FIG. 8, variations in heart rate and heart rate are controlled by variable resistor VR1
I tried to set it in VR2, but this data,
It may be registered in advance in the ROM, or it may be set using a key switch as shown in FIG. As described above, according to the present invention, it is possible to measure heart rate without taking your hands off the steering wheel.
In addition, since the presence or absence of an abnormality is identified from the measured heartbeat signal according to the magnitude of the value that corresponds to the degree of variation in the heartbeat cycle, it is possible to detect whether the driver is drowsy while driving.
By issuing a warning, traffic accidents can be prevented.

[Brief explanation of drawings]

Fig. 1a is a front view showing the vicinity of the steering wheel of a type of automobile embodying the present invention;
The figure is an enlarged sectional view taken along line Ib-Ib in Figure 1a, Figure 2 is a block diagram showing the configuration of the electric circuit of the device shown in Figure 1a, and Figure 3 is the microcomputer shown in Figure 2.
This is a flowchart showing the operation of the CPU. Fourth
5 is an enlarged sectional view of another embodiment of the present invention showing the same part as FIG. 1b, FIG. 5 is a block diagram of the electric circuit of the device, and FIGS. It is a flowchart showing the operation of a computer CPU. FIG. 7 is a waveform diagram showing an example of an electrocardiogram waveform, FIG. 8 is an electrical block diagram showing another embodiment of the present invention, and FIG. 9 is a flowchart showing the operation of the microcomputer CPU shown in FIG. FIG. 10 is a timing chart showing the signal at the INT end of the CPU and the operation timing of the CPU. 1: Steering wheel, 2, 3: Spokes, 4: Center pad, 5, 6: Detector (heartbeat detection means), 7, 8, 9, 10: Switch, 11, 1
2: Light emitting diode indicator, 13: Light emitting diode indicator, 14: 7 segment light emitting diode indicator, PD1: Light emitting diode (light emitting means), PT
1: Photo transistor (light receiving means), CPU: Microcomputer (control means), SP: Spring (elastic member), VGU: Audio output device, BZ: Buzzer (abnormality warning means), DSP: Display circuit, OSC:
Oscillator (light emission energizing means).

Claims (1)

[Scope of Claims] 1. Heartbeat detection means including a light-emitting means and a light-receiving means, which are arranged close to each other on a wheel or spoke of a steering wheel or an operation board on the steering wheel; a light-emitting device that energizes the light-emitting means to emit light; energizing means; instructing the light emitting energizing means to energize the light, measuring a plurality of cycles of each heartbeat signal obtained from the light receiving means, and based on the values of the plurality of heartbeat cycles obtained by the measurements; a control means for detecting a value indicating the degree of variation, and identifying the presence or absence of an abnormality according to the magnitude of the value indicating the degree of variation;
and Abnormality warning means that issues a warning by at least one of display and sound output when the control means identifies the presence of an abnormality; An on-vehicle heart rate monitor. 2. The control means detects the maximum value of the difference between adjacent heartbeat cycles of a plurality of continuously sampled heartbeat cycles as a value indicating the degree of variation in the heartbeat cycles. 1
On-vehicle heart rate monitor described in section. 3. The control means detects the heart rate by measuring the heartbeat signal obtained from the heartbeat detection means, and when the detected heart rate is smaller than a predetermined value and a value indicating the degree of variation in the detected heartbeat cycle is larger than a predetermined value. The on-vehicle heart rate monitor according to claim 1, which issues a warning. 4. The on-vehicle heart rate monitor according to claim 1, wherein the control means includes a sensitivity display means for displaying a display according to the amplitude of the signal from the light receiving means. 5. The on-vehicle heart rate monitor according to claim 1, wherein the light emitting means and the light receiving means are fixed to a key supported via an elastic member. 6. The on-vehicle heart rate monitor according to claim 5, wherein the elastic member is a spring. 7. The on-vehicle heart rate monitor according to claim 1, wherein the control means includes a switch means, and starts heart rate measurement in response to a change in the state of the switch means. 8. The on-vehicle heart rate monitor according to claim 7, wherein the switch means is disposed within a range of the palm of the hand, including at least the pads of the fingers, from the light emitting means and the light receiving means. 9. The light emitting means and the light receiving means are arranged in spokes that support the steering wheel.
The on-vehicle heart rate monitor according to item 5, item 6, item 7, or item 8.