CN204520642U - A kind of double light path pulse transducer - Google Patents
A kind of double light path pulse transducer Download PDFInfo
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- CN204520642U CN204520642U CN201420780687.0U CN201420780687U CN204520642U CN 204520642 U CN204520642 U CN 204520642U CN 201420780687 U CN201420780687 U CN 201420780687U CN 204520642 U CN204520642 U CN 204520642U
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- sensitive diode
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Abstract
The utility model discloses a kind of double light path pulse transducer, in this double light path pulse transducer, constant-current source circuit, light emitting diode, double light path circuit, light sensitive diode bridge circuit, pulse signal pick-up circuit, second amplifying circuit, wave filter, waveform shaping circuit, A/D change-over circuit, single-chip microcomputer are connected successively with charactron.Described double light path circuit is for reducing stray light; Described light sensitive diode bridge circuit, the error that the different qualities for overcoming two light sensitive diodes brings; Described chip microcontroller pulse display.This utility model structure is simple, microminiaturized, domestic, and sensitivity, degree of accuracy are high.
Description
Technical field
This utility model relates to field of photoelectric technology, particularly the sensor of the human body physiological parameter such as pulse.
Background technology
Contain abundant physiologic information in human pulse signal, be significant to clinical.Under normal conditions, the measurement for pulse is mainly divided into two kinds of forms, and a kind of is feeling the pulse of Traditional Chinese Medicine, but this form relies on the experience of individual often, and error is comparatively large, does not have generalization.Another kind carries out indirect inspection by sensor.But the signal measured is weak, be disturbed large.The design quality of sensor has direct impact to measurement result.
Along with the continuous progress of society, people more pay attention to health, therefore design a kind of portable, domestic, that precision is high sensor and just seem particularly important.
Photoelectric sensor has the response speed of high-resolution and agility, is the mainstream sensor surveying now pulse.Its structure comprises light path and circuit, and present most sensor is all utilize transmission-type, reflective method to obtain information in light path.But when having dust owing to having in light path in stray light (as the veiling glare such as sunlight, light) and light path, will measurement error be caused.Authorization Notice No. is: CN203724078 U, authorized announcement date are 2014.07.23, and the utility model patent of a kind of photoelectric sphyg sensor by name, utilizes light sensitive diode as photoelectric cell, have reasonable photoelectric characteristic and sensitiveer response characteristic.But because light sensitive diode itself has dark current (generally increasing with the rising of temperature), circuit can not stably be worked.And this patent is display pulse number of times, can not knows whether it is the number of times of one minute pulse, more can not know that whether oneself is healthy within the scope of this.
Summary of the invention
For the deficiency of above-mentioned technology, what the utility model proposes utilizes double light path photoelectric sensor to measure pulse signal, can reduce above-mentioned error.And overcoming the inconsistent of two photodiode elements characteristics by temperature-compensating electric bridge, sensitivity drift, temperature drift does not wait the impact brought.Pulse display is realized, alarm, the function of LED luminescence by single-chip microcomputer.This utility model structure is simple, microminiaturized, domestic, and sensitivity, degree of accuracy are high, do not need Professional knowledge can realize the measurement of oneself pulse, obtain desired parameters, thus judge health condition, be especially convenient to the use of old man and child.
The technical scheme of this utility model technical solution problem is: a kind of double light path pulse transducer, comprises constant-current source circuit, light emitting diode, double light path circuit, light sensitive diode bridge circuit, pulse signal pick-up circuit, second amplifying circuit, wave filter, waveform shaping circuit, A/D change-over circuit, single-chip microcomputer, charactron; Described constant-current source circuit, light emitting diode, double light path circuit, light sensitive diode bridge circuit, pulse signal pick-up circuit, second amplifying circuit, wave filter, waveform shaping circuit, A/D change-over circuit, single-chip microcomputer are connected successively with charactron; Described double light path circuit is for reducing stray light; Described light sensitive diode bridge circuit, the error that the different qualities for overcoming two light sensitive diodes brings; Described numeral method pulses measure result.
As further improvement, in described light sensitive diode bridge circuit, voltage U 0 one end connects swept resistance R1 and light sensitive diode D1 respectively, the other end of voltage U 0 is connected after swept resistance R1 and resistance R3 connect, light sensitive diode D1 is series resistance R2, light sensitive diode D2 successively, the positive pole of light sensitive diode D2 connects the other end of voltage U 0, and resistance R4 is connected in parallel on light sensitive diode D2.
As further improvement, in described double light path circuit, the light sent using described light emitting diode is as light source, be divided into two light paths, one tunnel is through reflecting mirror A, collimating mirror A, wedge and condenser lens A, enter a light sensitive diode in light sensitive diode bridge circuit, another road, through reflecting mirror B, collimating mirror B, body to be measured and condenser lens B, enters another light sensitive diode in light sensitive diode bridge circuit.
As further improvement, two light sensitive diodes in described light sensitive diode bridge circuit adopt PIN light sensitive diode.
As further improvement, described wave filter is second-order low-pass filter.
As further improvement, described single-chip microcomputer also connects buzzer and LED, realizes alarm function by buzzer, and whether normal by the red green display pulse of LED, green light is normally.
The beneficial effects of the utility model are: measure pulse with double light path pulse transducer, solve the problem that small-signal is easily subject to external electromagnetic signal disturbing, eliminate the impact of bias light.The impact that the discordance, sensitivity difference, drift etc. that adopt light sensitive diode bridge circuit to overcome two light sensitive diodes are brought.Second amplifying circuit and wave filter achieve the after-treatment to signal, ensure that the signal after amplifying easily is identified process, the Hz noise of filtering 50Hz.Use chip microcontroller is microminiaturized.Single-chip microcomputer is connected with charactron, buzzer and LED.Charactron low price, structure is simple; When reaching one minute, buzzer rings, more more accurate than manual time-keeping; LED is simple and clear, realizes domestic.
Accompanying drawing explanation
Fig. 1 is theory diagram of the present utility model
Fig. 2 is the schematic diagram of double light path circuit in this utility model
Fig. 3 is monolithic processor controlled module map in this utility model
Fig. 4 is light sensitive diode bridge circuit schematic diagram in this utility model
Fig. 5 is the schematic diagram of second-order low-pass filter in this utility model
In figure, 1: constant-current source circuit; 2: light emitting diode; 3: double light path circuit; 4: light sensitive diode bridge circuit; 5: pulse signal pick-up circuit; 6: second amplifying circuit; 7: wave filter; 8: waveform shaping circuit; 9:A/D change-over circuit; 10: single-chip microcomputer; 11: charactron; 12: buzzer; 13:LED lamp; 101-1: reflecting mirror A; 101-2: reflecting mirror B; 102-1: collimating mirror A; 102-2: collimating mirror B; 103: wedge; 104-1: condenser lens A; 104-2: condenser lens B; 105: body to be measured.
Detailed description of the invention
Below in conjunction with the drawings and specific embodiments, this utility model is described in further detail:
As Fig. 1,2, when measuring, constant-current source circuit 1, by Zener diode voltage stabilizing, can reduce light source power supply fluctuation to the impact of measuring pulse signal as far as possible, make the current constant flowing through light emitting diode 2, therefore light emitting diode 2 can the infrared light of stable output light intensity.After infrared light enters double light path circuit 3, be divided into two light paths, a road, through reflecting mirror A101-1, through collimating mirror A102-1 and absorption wedge 103, enters condenser lens A104-1, is formed and compensate light path; Another road, through reflecting mirror B101-2, after collimating mirror B102-2, transmitted through determinand 105, enters condenser lens B104-2, forms optical path.In optical path, infrared transmission crosses body 105 to be measured, and the hands being generally human body refers to; Through blood absorption and the decay of finger tissue, adjustment absorbs the position of wedge 103, changes luminous flux, and two light paths are exported equal, the electric bridge of light sensitive diode bridge circuit 4 reaches balance, and now, the position absorbing wedge 103 just reflects measured size.Cause light quantity to fluctuate when light source fluctuation and stray light (as the veiling glare such as sunlight, light), dust affects time, because two light paths of double light path circuit 3 are affected simultaneously, therefore these interference and affect and will be cancelled.In light sensitive diode bridge circuit, the luminous flux phi 1 that two light sensitive diodes receive is not equal to Φ 2, and Φ 1/ Φ 2=n.Because of reasons such as mains fluctuations, light source output light flux is changed, luminous flux in two light paths also will change, its changing value is △ Φ 1 and △ Φ 2, both sides relation is △ Φ 1/ △ Φ 2=n, namely two beam luminous flux are respectively by Φ 1=Φ 1+ △ Φ 1 and Φ 2=Φ 2+ △ Φ 2, the luminous flux difference received is △ Φ=Φ 1-Φ 2=(Φ 1+ △ Φ 1)-(Φ 2+ △ Φ 2)=Φ 1-Φ 2+ △ Φ 1(1-n), in formula, the right Section 1 is original signal, Section 2 is because of the error caused that fluctuates, work as n->1, △ Φ 1(1-n)->0.
And realize the light sensitive diode bridge circuit 4 of temperature-compensating, the impact that two light sensitive diodes cause error (sensitivity error, temperature drift, dark current etc.) to be brought due to characteristic difference own can be overcome.After the optical signal of reception is converted to the signal of telecommunication by light sensitive diode bridge circuit 4, gather through pulse signal pick-up circuit 5 pairs of signals of telecommunication again, and amplified by second amplifying circuit 6 pairs of signals, after again through second-order low-pass filter filtering obtain low-pass signal.
As shown in Figure 5, the circuit diagram of second-order low-pass filter is: after resistance R1, R2 series connection, the in-phase input end of access left-hand amplifier, and the inverting input of left-hand amplifier is connected with outfan, and the in-phase input end of left-hand amplifier connects ground connection after an electric capacity C3.Electric capacity C1 one end is connected in the middle of resistance R1 and R2, and the other end of electric capacity C1 is connected with the outfan of left-hand amplifier.After outfan contact resistance R3, R4 of left-hand amplifier, the in-phase input end of access right-hand amplifier, the inverting input of right-hand amplifier is connected with outfan, and the in-phase input end of right-hand amplifier connects ground connection after an electric capacity C4.Electric capacity C2 one end is connected between resistance R3 and R4, and the other end of electric capacity C2 is connected with the outfan of right-hand amplifier.The low-pass signal obtained is admitted to waveform shaping circuit 8, is converted to digital signal by A/D change-over circuit 9, input single-chip microcomputer 10.
As shown in Figure 3, single-chip microcomputer 10 connects charactron 11, buzzer 12, LED 13.When starting to measure, single-chip microcomputer 10 is started working and is realized one minute counting.One time pulse is beaten, and single-chip microcomputer 10 just counts once, and is shown the number of times of meter by charactron 11.When one minute then, single-chip microcomputer 10 makes buzzer 12 sound, and LED 13 is bright.LED 13 green light then represents normal, and infant pulse is 130 ~ 150 beats/min under normal circumstances, child 110 ~ 120 beats/min, adult normal 60 ~ 100 beats/min, and old people can slowly to 55 ~ 75 beats/min; Not then LED 13 when red within the scope of this.Single-chip microcomputer 10 quits work afterwards, and counting stops, and waits for and measuring next time.
Due to the change in periodically pulsing in blood circulation process of finger arterial blood, so it is also periodically pulsing to the absorption of light and decay, so the change that light sensitive diode bridge circuit 4 outputs signal also just reflects the pulsatile change of arterial blood.Because employ double light path circuit, the interference of stray light and dust can be reduced.Use light sensitive diode bridge circuit to reduce drift, add the degree of accuracy of measurement, and adopt PIN light sensitive diode to make response speed faster.But PIN light sensitive diode has a fatal defect---output current is less, and adopts second amplifying circuit can amplifying signal, and amplification coefficient more greatly 50-100, makes reaction more sensitive.
In order to reduce measurement error further, in double light path circuit, zero correction to be carried out by two wedge before measuring, make two light sensitive diodes in light sensitive diode bridge circuit, the luminous flux received under identical condition is equal, and then makes certainty of measurement more accurate.
Claims (6)
1. a double light path pulse transducer, is characterized in that: comprise constant-current source circuit (1), light emitting diode (2), double light path circuit (3), light sensitive diode bridge circuit (4), pulse signal pick-up circuit (5), second amplifying circuit (6), wave filter (7), waveform shaping circuit (8), A/D change-over circuit (9), single-chip microcomputer (10), charactron (11); Described constant-current source circuit (1), light emitting diode (2), double light path circuit (3), light sensitive diode bridge circuit (4), pulse signal pick-up circuit (5), second amplifying circuit (6), wave filter (7), waveform shaping circuit (8), A/D change-over circuit (9), single-chip microcomputer (10) are connected successively with charactron (11); Described double light path circuit (3) is for reducing stray light; Described light sensitive diode bridge circuit (4), the error that the different qualities for overcoming two light sensitive diodes brings; Described charactron (11) display pulse measurement result.
2. a kind of double light path pulse transducer according to claim 1, it is characterized in that: in described light sensitive diode bridge circuit (4), voltage U 0 one end connects swept resistance R1 and light sensitive diode D1 respectively, the other end of voltage U 0 is connected after swept resistance R1 and resistance R3 connect, light sensitive diode D1 is series resistance R2, light sensitive diode D2 successively, the positive pole of light sensitive diode D2 connects the other end of voltage U 0, and resistance R4 is connected in parallel on light sensitive diode D2.
3. a kind of double light path pulse transducer according to claim 1, it is characterized in that: in described double light path circuit (3), the light sent using described light emitting diode (2) is as light source, be divided into two light paths, one tunnel is through reflecting mirror A (101-1), collimating mirror A (102-1), wedge (103) and condenser lens A (104-1), enter a light sensitive diode in light sensitive diode bridge circuit (4), another road is through reflecting mirror B (101-2), collimating mirror B (102-2), body to be measured (105) and condenser lens B (104-2), enter another light sensitive diode in light sensitive diode bridge circuit (4).
4. a kind of double light path pulse transducer according to claim 2, is characterized in that: two light sensitive diodes in described light sensitive diode bridge circuit (4) adopt PIN light sensitive diode.
5. a kind of double light path pulse transducer according to Claims 1-4 any one, is characterized in that: described wave filter (7) is second-order low-pass filter.
6. a kind of double light path pulse transducer according to Claims 1-4 any one, is characterized in that: described single-chip microcomputer (10) also connects buzzer (12) and LED (13).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420780687.0U CN204520642U (en) | 2014-12-12 | 2014-12-12 | A kind of double light path pulse transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420780687.0U CN204520642U (en) | 2014-12-12 | 2014-12-12 | A kind of double light path pulse transducer |
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| Publication Number | Publication Date |
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| CN204520642U true CN204520642U (en) | 2015-08-05 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420780687.0U Expired - Fee Related CN204520642U (en) | 2014-12-12 | 2014-12-12 | A kind of double light path pulse transducer |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106923798A (en) * | 2017-04-12 | 2017-07-07 | 亿信标准认证集团有限公司 | The pulse monitoring equipment of employing wireless transmission |
| WO2018206014A1 (en) | 2017-05-12 | 2018-11-15 | 杭州兆观传感科技有限公司 | Dual optical path sensor module |
-
2014
- 2014-12-12 CN CN201420780687.0U patent/CN204520642U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106923798A (en) * | 2017-04-12 | 2017-07-07 | 亿信标准认证集团有限公司 | The pulse monitoring equipment of employing wireless transmission |
| WO2018206014A1 (en) | 2017-05-12 | 2018-11-15 | 杭州兆观传感科技有限公司 | Dual optical path sensor module |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150805 Termination date: 20151212 |
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| EXPY | Termination of patent right or utility model |