JPH0230685B2 - - Google Patents

Description

[Detailed description of the invention]

[Purpose of the Invention] (Industrial Application Field) The present invention relates to an on-vehicle heart rate monitor that measures the heartbeat of a driver, etc. on a vehicle, and in particular, a sensor equipped with a steering wheel that outputs an electrical signal according to the human heartbeat. Regarding in-vehicle heart rate monitors. (Prior Art) When driving a vehicle, if the driver's health condition is not favorable, there is a high possibility that an accident will occur.
For example, if you continue to drive for a long period of time without taking a break, fatigue accumulates, your health condition worsens, and your concentration deteriorates. 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 who drives 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. In other words, in this type of general heart rate monitor, a light emitting diode, a photodiode, etc. are protruded from a substrate to form a reflective photo sensor, and this sensor is applied to the pad of a person's finger to further reduce the influence of extraneous light. To avoid this problem, the sensor and fingers are covered with black sponge, etc., making it extremely difficult for drivers to drive while wearing this on their fingers. Moreover, when this type of sensor is used, if the finger is moved during measurement, the sensor and finger become misaligned, making measurement impossible, and the person being measured is required to rest. Therefore, the present applicant has proposed an on-vehicle heart rate monitor (Japanese Patent Application No. 132,847/1982) that is capable of measuring heart rate even while driving the vehicle by equipping the steering wheel with a sensor for detecting heart rate. (Problem to be solved by the invention) However, in this case, by embedding the heart rate sensor in the steering wheel, heart rate can be measured even while driving the vehicle, but on the other hand, the heart rate sensor is integrated with the steering wheel. Therefore, in order to have an on-board heart rate monitor,
The steering wheel itself needs to be replaced with one equipped with a heart rate sensor. SUMMARY OF THE INVENTION An object of the present invention is to provide an on-vehicle heart rate monitor that can measure heart rate even while driving a vehicle, and to facilitate attachment and detachment of the on-vehicle heart rate meter. [Structure of the Invention] (Means for Solving the Problems) For this purpose, in the present invention, the light emitting means and the light receiving means are arranged on the steering wheel cover. (Function) According to this, since it is relatively easy to attach and detach the steering wheel cover, the on-vehicle heart rate monitor can be easily attached and detached. By the way, if the heart rate sensor attached to the steering wheel cover and the main body of the device are connected by a line, this will hinder the driving operation. Therefore, in one preferred embodiment of the present invention, the heart rate sensor and the device are provided with a signal transmitting means for transmitting the signal of the heart rate sensor as a radio wave, and a signal receiving means for receiving the signal and demodulating the signal in the main body of the device. Connect everything with radio waves and eliminate wires. Furthermore, this signal transmitting means can be attached to and detached from the steering wheel spoke. Further, in one preferred embodiment of the present invention, a plurality of light receiving elements are arranged around the light emitting element so as to surround it, and the optical axes of the light emitting element and the light receiving element are directed in substantially the same direction. At least one detection unit is provided on the steering wheel cover. According to this, the heartbeat signal can be extracted from the palm of the hand, and the heartbeat can be measured in a natural manner even while driving. While driving a vehicle, there are times when it is desired to change the positional relationship between the steering wheel and the hands, such as when changing the direction of travel. Furthermore, the positions in which the steering wheel is held vary depending on the driver. Therefore, in one preferred embodiment of the present invention, a plurality of detection units are arranged on the steering wheel cover at a predetermined interval from each other so that the heartbeat signal can be detected no matter where the driver grips the steering wheel. do. (Example) Fig. 1 shows a steering wheel cover 10 in which an on-vehicle heart rate monitor according to an embodiment is arranged, Fig. 2 shows an enlarged view of section A in Fig. 1, and Fig. 3 shows an enlarged view of section A in Fig. 1. FIG. 2 shows a - sectional view. First, explanation will be given with reference to FIG. On the back side of the steering wheel cover (hereinafter referred to as cover) 10, eight reflective optical sensors SE1, SE2, SE3, SE4, SE5,
SE6, SE7, and SE8 are arranged dispersedly from each other. All optical sensors (SE1 to SE8) have the same configuration. To explain only the optical sensor SE1, the optical sensor SE1 consists of one light emitting diode LE1 and four phototransistors PT arranged around it.
Equipped with 1, PT2, PT3, and PT4. The light emitting diode LE1 and phototransistors PT1 to PT4 of the optical sensor SE1 have their optical axes oriented in the same direction (toward the outside in the radial direction of the steering wheel when attached to the steering wheel, which will be described later). Note that the light emitting diodes provided in each of the optical sensors SE1 to SE8 are infrared light emitting diodes that emit light in the infrared region. Each of the optical sensors SE1 to SE8 is wired by an electric wire 12 formed on a flexible substrate 11 (see FIG. 2). An end of the flexible substrate 11 is connected to a transmitting device 20 that includes a light emitting energizing means and a signal transmitting means. Further, the flexible substrate 11 is bonded to the cover 10 with an adhesive 13 (see FIG. 3). A battery box 30 is connected to the transmitter 20 by an electric wire 31. A support member 40 is disposed on each of the transmitting device 20 and the battery box 30, and both ends of the support member 40 are provided with cotton tapes 40a and 40b, respectively. Note that the cover 10 is provided with a through hole 10a for attaching the cover 10 to a steering wheel. Next, FIGS. 4 and 5 show a state in which the cover 10 is attached to the steering wheel 50. The cover 10 is attached to the front side of the steering wheel 50 using a fastening string 60 so that each of the optical sensors SE1 to SE8 is arranged (see FIG. 4). Moreover, on the back side of the steering wheel 50,
A transmitting device 20 and a battery box 30 are attached to the spokes 51, 51, respectively (see FIG. 5). The transmitting device 20 and the battery box 30 are fixed by winding the support member 40 around the spokes 51 and gluing cotton tapes 40a and 40b arranged at the ends of the support member 40. FIG. 6 shows the circuit configuration of the electronic circuit 200 and sensor unit SWU built into the transmitting device 20.
This will be explained with reference to FIG. The oscillation circuit OSC1 is
It is an astable multivibrator circuit, and in this example outputs a 1KHz square wave signal. The light emitting diodes LE1, LE2, etc. of the eight optical sensors SE1 to SE8 of the sensor unit SEU are connected in series, and one end thereof is connected to the output terminal of the oscillation circuit OSC1. Therefore, the light emitting diode LE1 of each optical sensor,
All LE2 etc. are lit intermittently at a cycle of 1 msec. When any of the optical sensors SE1 to SE8 is positioned facing a human blood vessel, the light reflectance of that portion varies depending on the blood flow rate, that is, the heartbeat. Therefore, at the output terminal of the phototransistor of the optical sensor, a 1 KHz AC signal whose amplitude is modulated according to the heartbeat signal is obtained. The phototransistors PT1 to PT4 of each optical sensor SE1 to SE8 are connected in parallel with each other, and one end is connected to the amplifier AM1 and the low-pass filter.
The signal passes through LP1, amplifier AM2, low-pass filter LP2, and amplifier AM3, and is converted into a heartbeat signal as shown in FIG. This heartbeat signal is
(amplitude modulation) applied to the modulator AMM. modulator
A 1 KHz signal from the oscillation circuit OSC1 is applied to one end of the AMM, and this signal is converted into a sine wave by a filter and then amplitude-modulated according to the level of the heartbeat signal. The output signal of the modulator AMM passes through the FM (frequency modulation) modulator FMM, passes through the power amplifier PA, and is radiated from the transmitting antenna as a radio wave. The heartbeat signal has a very low frequency of about 1 Hz, and if it is transmitted directly over radio waves, it is difficult for the receiving side to demodulate the signal. Therefore, in this embodiment, the heartbeat signal is amplitude-modulated and converted to a relatively high frequency of 1 KHz, and then frequency-modulated to transmit this signal onto radio waves. FIG. 8 shows the heartbeat detection unit (transmission device 2).
2 shows the circuit configuration of a data receiving unit that receives signals from 00) and performs various processing. This will be explained with reference to FIG. A microcomputer controls the entire circuit
It is the CPU. The microcomputer CPU has
Oscillation circuit OSC2, voice synthesizer VGU, video memory VRAM1, VRAM2, buzzer BZ, A/D
Converter ADC, key switches SW1, SW2, etc. are connected. Key switch SW1 and
The circuit provided between SW2 and the microcomputer CPU is a waveform shaping circuit. speech synthesizer
A speaker SP is connected to the output terminal of the VGU, and cathode ray tube display devices CRT1 and CRT2 are connected to the video memories VRAM1 and VRAM2, respectively. Variable resistors VR1 and VR2 for setting the reference level are connected to input terminals 1 and 2 of the A/D converter ADC, respectively.
The input terminal 3 is connected to the output terminal of the demodulation circuit DEM. The data receiving unit is equipped with an FM receiver RX connected to the receiving antenna RAN, and is tuned to the frequency of radio waves emitted by the heartbeat detection unit.
At the output of the FM receiver RX, a signal from the heartbeat detection unit is obtained. Since the FM receiver RX demodulates the frequency modulated signal, a 1KHz signal amplitude modulated by the heartbeat signal is obtained at these output terminals.
The output terminal of the FM receiver RX is connected to the AM demodulator DEM.
is connected. The AM demodulator DEM consists of an amplifier AM4 and a low-pass filter, as shown in Figure 9.
LP3, amplifier AM5, low pass filter LP4,
It is equipped with an AM6 amplifier etc. AM demodulator DEM
A heartbeat signal detected by a heartbeat detection unit is obtained at the output terminal of the heartbeat detection unit. Figure 10 shows the microcomputer in Figure 8.
This shows the general operation of the CPU. The operation will be explained with reference to FIG. First, interrupt processing will be explained. Since the signal from the oscillation circuit OSC2 is applied to the interrupt input terminal INT of the CPU, the CPU executes interrupt processing at predetermined intervals. In this interrupt processing, the contents of register N are incremented (+1). In other words, the contents of register N change depending on the elapsed time, so if you clear the contents of N to 0 at a certain timing, by checking the value of N in the main routine, you can check the elapsed time since clearing. I understand. In the main routine, subroutine, etc., various processing timings are determined by checking the value of this register N. Next, the main routine will be explained. When the power is turned on, first check the start switch SW1. When this is turned on, the voltage set by variable resistors VR1 and VR2 is transferred to the A/D converter.
Convert it to a digital signal with ADC and store the converted data in registers MH and ML. The data in registers MH and ML serve as the heartbeat cycle variation upper limit value and heart rate lower limit value, respectively, for determining whether or not to issue an alarm. Table 1 below shows the average heart rate of 1/L.
and the variability (i.e. variance) of the heartbeat cycle △L
Outlines the relationship between this and a person's physical and mental state.

【table】

〔effect〕

As described above, according to the present invention, the heartbeat detection unit can be easily attached to and detached from the steering wheel. In particular, by separating the detection part and the main body of the device and wirelessly transmitting the heartbeat signal as in the embodiment, the device can be made more compact, and there is no longer any wiring connecting the detection part and the main body of the device, which can interfere with driving operations. Not at all.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the heartbeat detection unit of the embodiment attached to the steering wheel cover;
Figure 2 is a partially enlarged view of Figure 1, Figure 3 is a cross-sectional view of Figure 2, and Figures 4 and 5 are plan views showing where the heart rate detection unit of Figure 1 is attached to the steering wheel. , FIG. 6 is an electric circuit diagram showing the configuration of the internal electronic circuit of the transmitter 20 shown in FIG. 1, FIG. 7 is a waveform diagram showing an example of the heartbeat signal waveform, and FIG. A block diagram showing the circuit configuration of the receiving device main body, Fig. 9 is similar to Fig. 8.
1 is an electrical circuit showing one configuration of an AM demodulator.
Figure 10 shows the microcomputer CPU shown in Figure 8.
1 is a flowchart showing a schematic operation of the 10: Steering wheel cover, 11: Flexible circuit board, 20: Transmitting device (signal transmitting means), 30: Battery box, 40: Indicating member, 40a, 40b: Cotton tape, 50: Steering wheel, 51: Spoke, SE1: Optical Sensor (heartbeat detection means), SEU: sensor unit,
LE1: Light emitting diode (light emitting means), PT1, PT
2, PT3, PT4: Phototransistor (light receiving means), SW1: Start switch, SW2: Cancel switch, OSC1: Oscillator circuit (light emission means), VGU: Voice synthesizer (notification means), CRT
1, CRT2: Cathode ray tube display device, DEM: Demodulation circuit, CPU: Microcomputer (electronic control means).

Claims (1)

[Scope of Claims] 1 Steering wheel; Light emitting means; Light receiving means disposed near the light emitting means; Light emitting energizing means for energizing the light emitting means; Notification means for at least one of display and sound output; The light receiving means an electronic control means that calculates a value according to the number of fluctuations per predetermined time or a fluctuation period of the electric signal from the means, and energizes the notification means according to the result; and an electronic control means that covers the steering wheel and is detachable. An on-vehicle heart rate meter comprising: a steering wheel cover, wherein the light emitting means and the light receiving means are arranged on the steering wheel cover. 2. The electronic control device is provided with a signal transmitting means for outputting a radio wave modulated by an electrical signal from the light receiving means, and a signal receiving means for receiving the radio wave and demodulating a heartbeat signal. On-board heart rate monitor. 3. The on-vehicle heart rate monitor according to claim 2, wherein the light emitting energizing means and the signal transmitting means are detachably disposed on the steering wheel spoke. 4. The on-vehicle heart rate monitor according to claim 1, wherein the light receiving means is disposed near the light emitting means in a position surrounding the light emitting means with its optical axis directed in substantially the same direction as the light emitting means. 5. The on-vehicle heart rate monitor according to claim 4, wherein the light emitting means and the light receiving means are arranged in plural sets at positions separated from each other on the steering wheel cover.