實現非接觸主動式電極以量測心律之研究
Study of Implementing Non-contact Active
Electrodes to Measure the Heart Rate
Adviser: Huang Ji-Jer
Presenter:Chou Hou-Yu
Date:2014/10/22
OUTLINE
1.
Introduction
1.
2.
2.
3.
Paper Review
Materials and Methods
1.
4.
Analog circuits
Results
1.
5.
Brief introduction
ECG, PPG ,FET background and principles
Analog circuit analysis and measurement
Conclusions and Future Work
1. Introduction
Demographic analysis

表一、戶籍登記現住人口數按年齡分
年齡結構百分比 (％)
戶籍人口登記數
年底別
民國92年底
民國93年底
民國94年底
民國95年底
民國96年底
民國97年底
民國98年底
民國99年底
民國100年底
民國101年底
民國102年底
較101年底
增減率(％)
總增加 自然增 社會增
0-14歲
率(‰) 加率(‰) 加率(‰)
22,604,550
3.71
4.27
-0.55
19.83
人數
22,689,122
22,770,383
22,876,527
22,958,360
23,037,031
23,119,772
23,162,123
23,224,912
23,315,822
23,373,517
3.73
3.58
4.65
3.57
3.42
3.59
1.83
2.71
3.91
2.47
3.59
2.92
3.01
2.76
2.40
2.07
0.91
1.88
3.23
1.85
0.25 ②-1.44 ②-1.38
0.14
0.65
1.64
0.81
1.02
1.52
0.92
0.82
0.67
0.62
②-0.05
性別比例 扶養比
15-64歲 65歲以上 (女=100) (％) 扶幼比 扶老比
老化
指數
(％)
70.94
9.24
103.84
40.97
27.95
13.02
46.58
71.19
71.56
71.88
72.24
72.62
73.03
73.61
74.04
74.22
74.15
9.48
9.74
10.00
10.21
10.43
10.63
10.74
10.89
11.15
11.53
103.53
103.16
102.72
102.28
101.89
101.34
100.94
100.57
100.26
99.96
40.48
39.74
39.12
38.43
37.70
36.93
35.85
35.07
34.74
34.85
27.16
26.14
25.21
24.30
23.34
22.38
21.26
20.37
19.72
19.31
13.31
13.60
13.91
14.13
14.36
14.56
14.59
14.70
15.03
15.55
49.02
52.05
55.17
58.13
61.51
65.05
68.64
72.20
76.21
80.51
①-0.31 ①-0.07
①0.38
19.34
18.70
18.12
17.56
16.95
16.34
15.65
15.08
14.63
14.32
①-0.30 ①0.11 ①-0.41 ①0.52 ①4.30
資料來源：本部戶政司。
說　明：1.自然增加率=(出生人數－死亡人數)÷年中人口數×1,000。
2.社會增加率=(遷入人口數－遷出人口數)÷年中人口數×1,000。
3.總增加率=自然增加率+社會增加率。
4.性別比例=(男性人口數/女性人口數)*100。
5.扶養比=(0-14歲人口+65歲以上人口)/(15-64歲人口)*100。
6.扶幼比=(0-14歲人口)/(15-64歲人口)*100。
7.扶老比=(65歲以上人口)/(15-64歲人口)*100。
8.老化指數=(65歲以上人口)/(0-14歲人口)*100。
備
註：①係指增減百分點。
②係指增減千分點。
內政部統計處 http://www.moi.gov.tw/stat/news_content.aspx?sn=8057 103/10/13
1. Introduction
• 2013 statistical results on causes of death in Taiwan
順
位
1
2
合
ICD-10
國際死因
分類號碼
計
死亡
死 亡 原 因
人數
A00-Y98
所有死亡原因
C00-C97
惡性腫瘤
I01-I02.0, I05-I09,
心臟疾病（高血壓性疾病除外）
I20-I25, I27, I30-I52
每十萬人口
標準化
死亡率
死亡率
死亡
百分比
%
154,374
661.3
435.3
100.0
44,791
191.9
130.4
29.0
17,694
75.8
47.7
11.5
11,313
48.5
30.3
7.3
3
I60-I69
腦血管疾病
4
E10-E14
糖尿病
9,438
40.4
25.8
6.1
5
J12-J18
肺炎
9,042
38.7
22.5
5.9
6,619
28.4
22.4
4.3
6
V01-X59, Y85-Y86 事故傷害
7
J40-J47
慢性下呼吸道疾病
5,959
25.5
14.9
3.9
8
I10-I15
高血壓性疾病
5,033
21.6
12.9
3.3
9
K70, K73-K74
慢性肝病及肝硬化
4,843
20.7
14.8
3.1
4,489
19.2
11.9
2.9
35,153
150.6
101.8
22.8
10
N00-N07, N17-N19,
腎炎、腎病症候群及腎病變
N25-N27
其他
衛生福利部 http://www.mohw.gov.tw/cht/Ministry/DM2_P.aspx?f_list_no=7&fod_list_no=4558&doc_no=45347 103/10/13
1. Introduction
• ECG background and principles
◦ ECG records the heart in nerve conduction arising from
potential changes graphics
Photo Source : http://www.bostonscientific.com/lifebeat-online/heart-smart/electrical-system.html
1. Introduction
ECG:
Advantages:
Better signals
Disadvantages:
1. Skin irritations
2. Specific preparation
before
measurements
3. Limitations related
to the connecting
cables
http://140.134.32.60:83/news/test/biotech/bei/bei.html
102/12/9
1. Introduction
Capacitive ECG :
Advantages:
1. Does not need
contact
2. Make continuous for
long time monitor
3. An office chair, a
bed, a toilet seat ,
automobile
Disadvantages:
1. Still suffer from
strong artifacts
2.Paper Review
•
A Wireless Wearable ECG Sensor for
Long-Term Applications
 IEEE Communications Magazine • January
2012
 Ebrahim Nemati, M. Jamal Deen, and Tapas
Mondal, McMaster University
2.Paper Review

Schematic representation of the ECG system
architecture
2.Paper Review

Photograph of the designed PCBs

Frequency spectrum of the sensor
2.Paper Review
Reference Technologies
used
Implemen Advantages
tation
Limitation
s
Y.Yama
Capacitive
sensing
Integrated
on cloth
Flexible
electrodes — 24
mm × 41.7 mm
Large
FM
inconvenient transmitter
electrode
at 315
MHz
S. Fuhrhop
Capacitive
sensing
Integrated
on a belt
Flexible electrodes Poor
integrated into
filtering
garment
Bluetooth
A.Aleksand
rowicz
Capacitive
sensing
Integrated
on chair
Un-noticeable onchair electrodes –
4 cm × 8 cm
Not for
ambulatory
applications
Zebra
Zigbee
module
Integrated
on chair
Integrated onchair electrodes –
4 cm × 4 cm
Not for
ambulatory
applications,
—
Y. G. Lim, K. Capacitive
K. Kim
sensing, Active
shielding
Wireless
technology
2.Paper Review
Referen
ce
Technologie
s
used
Implementa Advantages
tion
Limitation
s
C. Park
Capacitive
sensing
Integrated on
cloth and belt
Fairly small
electrodes (15
mm diameter)
Extremely
Wireless
low-capacity module 2.4
battery
GHz
E. M.
Spinelli
Dry-electrode Integrated on
sensing,
Cloth
Active
shielding
Small electrodes
(down to
8 mm diameter)
Low signal
quality
BluesenseAD
module
Lowest power,
relatively small
sensor size,
ultra-thin
electrodes (2
mm)
Rigid
Electrodes
ANT module,
extremely low
power
— 1 mA
Proposed Capacitive
sensor
sensing
Integrated on
a stretchable
cloth
Wireless
technology
2.Paper Review
•
Designing Sensitive Wearable Capacitive Sensors for
Activity Recognition
 IEEE Sensors Journal, VOL. 13, NO. 10,
OCTOBER 2013
 Jingyuan Cheng, Oliver Amft, Gernot Bahle, and
Paul Lukowicz
2.Paper Review

Analog circuitry of our wearable capacitance measuring
approach
2.Paper Review

Simplified model of sensor and the human body
◦ Sensor pads (blue) , clothes (green), skin (yellow), muscle
(red)
◦ Use SEMCAD X
(a) Side view
(b) Top view (c) E-density distribution
2.Paper Review
Energy density alone the line crossing the center of one pad,with
E-field at 10 MHz and different clothes thickness
2.Paper Review
•
Thin and flexible active electrodes with shield for
capacitive electrocardiogram measurement
 International Federation for Medical and
Biological Engineering 2010
Med Biol Eng Comput (2010) 48:447–457
 Seung Min Lee , Kyo Sik Sim ,Ko Keun
Kim ,Yong Gyu Lim ,Kwang Suk Park
2.Paper Review
(a)Cross-sectional view of electrode,(b) Diagram of active electrode with feedback gain
to reduce stray capacitance,(c) Top view of electrode,(d) Electrode fixed onto two
fingers
2.Paper Review

The equivalent
circuit

Transfer function
2.Paper Review

The equivalent
circuit

Positive feedback can
make the amplifier
unstable and cause
oscillation, which can
be reduced by
decreasing feedback
gain
2.Paper Review

Shielding plate with guarding feedback
2.Paper Review

Effect of cloth thickness
◦ Cotton cloths, electrode were set to 45 cm²
C : The capacitance
A : The area of overlap of the two plates
εr : Dielectric constant( εr = 1 ,almost air)
ε0 : The electric constant (ε0 ≈ 8.854×10−12 F m–1
2.Paper Review

Effect of electrode area
2.Paper Review

Effect of contact pressure
2.Paper Review

ECG measurements
3.Materials and Methods

Capacitive coupling
electrode
—To capture the weak charge
with the capacitive coupling
electrode must place high
impedance and low noise
opamp,the induced charge via
the resistor (𝑅𝐵) ,converted
into a voltage signal output
3.Materials and Methods

The equivalent circuit

Explanation of terms
—𝐶𝑔:The stray capacitance
between the human and the
ground
—𝐶𝑚:The stray capacitance
between the instrument and
the ground
—Cs: The shielding plate
stray capacitance
—Rsk:Skin impedance
—Rc,CC: Active electrode
impedance
—Rin,Cin:OP impedance
3.Materials and Methods
2
1
1
) //
//( Rin //
)
sCm sCs
sCin
Vo  Vs
2
1
2
1
1
//{Rsk  Rc //(
)  [( Rb 
) //
//( Rin //
)]}
sCg
sCc
sCm sCs
sCin
2
1
2
1
[
// Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)
sCg
sCc
sCm
sCin
 AVo
1
2
1
2
1

//{[ Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)}
sCs sCg
sCc
sCm
sCin
( Rb 
∵
2
𝑆𝐶𝑔
≫
𝑅𝑠𝑘 + 𝑅𝑐//
1
𝑆𝐶𝑐
+
𝑅𝑏 +
2
𝑆𝐶𝑚
//
1
𝑆𝐶𝑠
// 𝑅𝑖𝑛//
1
𝑆𝐶𝑖𝑛
3.Materials and Methods
Cg
Óscas Casas ,2007 [1]
Cc Cm Cs
l
h
20
pF
Tobias Wartzek , 2011 [2]
200
pF
21
pF
Ko Keun Kim and Kwang Suk Park , 2008 [3]
200
pF
33
pF
Emad Alnasser , 2014 [4]
300
Pf
Ko Keun Kim , 2005 [5]
Seung Min Lee, 2010 [6]
Cin Rb Ri
n
500
pF
200
pF
500
pf
33
pF
18
40
pF
50
G
Ω
18
pF
1.6
G
Ω
18
Pf
1.6
G
Ω
5
3.Materials and Methods
∴
⇒
1
// Rb )
sCc
Vo  Vs
 AVo
1
1
1
1
( Rc //
)  ( Rb //
)
 ( Rc //
// Rb )
sCc
sCs
sCs
sCc
( Rb //
1
)
sCs
( Rc //
Vo
Rb (1  sRcCc )

Vs
Rb  Rc  sRbRc (1  A)Cs  Cc
3.Materials and Methods

Electrode
Gain(As)
As gain
(a)Eleg1n
b
NA

(a)
(b)
(b)Eleg01
(c)Eleg09
1
0.9
The equivalent circuit of
individual electrode
(c)
3.Materials and Methods

The verification experiment
—Analog circuit experiment ①
—Active electrode experiments
 Each electrode effect of cloth thickness ②
(Ⅰ)0.0mm (Ⅱ)0.2mm (Ⅲ)
0.4mm (Ⅳ)0.6mm
 Each electrode Effect of electrode area ③
144 cm²
2
3
0.1Hz~100Hz
正弦波
1
0.01Hz~1kHz
Sin signal
(Ⅰ) 45 cm² (Ⅱ) 100 cm² (Ⅲ)
3.Materials and Methods

The verification experiment
—ECG simulation experiment ④
 SNR
3.Materials and Methods
• Analog circuit experiment ①
—Use the NI USB-6356 to capture entity circuit output voltage
and integrate the data in Matlab
—Use the PSpice simulate the analog circuit and compare with
captured data then show the frequency response graph
3.Materials and Methods

Permittivity
A
C   r 0
d
C: Capacitance
A: Area
d: Distance
εr : Relative permittivity (εr= 1 ,almost air)
ε0: vacuum permittivity (ε0≈8.854×10−12F m–1)
http://zh.wikipedia.org/wiki/%E7%94%B5%E5%AE%B9%E7%8E%87#mediaviewer/File:Diel.gif
3.Materials and Methods
• Active electrode experiments
Each electrode effect of cloth thickness  The actual figure
②
—Cotton cloths with thicknesses of
(Ⅰ)0.0 mm、(Ⅱ)0.2 mm、 (Ⅲ) 0.4
mm and (Ⅳ)0.6 mm were inserted
between the electrode and the copper
plate
3.Materials and Methods
• Active electrode experiments
Each electrode Effect of electrode area ③
—The cloth thickness was selected as 0.2 mm
—Three active electrodes with different areas (Ⅰ) 45 cm²、 (Ⅱ) 100 cm²、
(Ⅲ) 144 cm² were examined
(Ⅰ) 45 cm²
(Ⅱ) 100 cm²
(Ⅲ) 144 cm²
3.Materials and Methods
• ECG simulation experiment
④
— The cloth thickness was selected
as 0.2 mm and active electrodes
was selected as 144 cm²
— FLUKE MPS450 simulat the
ECG signal,output voltage is 2
mv

The definition of SNR：Noise is
defined before 0.5Hz , 60 Hz and
after 100 Hz, signal is defined 0.5
Hz~59 Hz and 61 Hz~100 Hz
SNR = 10log
𝑃0.5𝐻𝑧~59𝐻𝑧 + 𝑃61𝐻𝑧~100𝐻𝑧
𝑃<0.5𝐻𝑧 + 𝑃60𝐻𝑧 + 𝑃>100𝐻𝑧
4. Results
• Analog circuit experiment
◦The actual circuit diagram
4. Results
• Analog circuit experiment
◦All filter and preamplifier
◦PSpice circuit simulation frequency response
4. Results
• Analog circuit experiment
◦ All filter and preamplifier circuit Bode
4. Results

Analog circuit experiment
◦ Combined the actual circuit result and Pspice result
4. Results
• Active electrode experiments
◦ The actual circuit diagram (Eleg1nb)
4. Results
• Active electrode experiments
◦ The actual circuit diagram (Eleg01)
4. Results
• Active electrode experiments
◦ The actual circuit diagram (Eleg09)
4. Results
• Active electrode experiments
— Each electrode effect of cloth thickness ②
(ｂ) Eleg01
(a) Eleg1nb
(c) Eleg09
4. Results
• Active electrode experiments
—Each electrode Effect of electrode area ③
(b) Eleg01
(a) Eleg1nb
(c) Eleg09
4. Results
• ECG simulation experiment ④(Area 144 cm², cloth thickness0.2 mm)
(a) Eleg1nb
(b) Eleg01
(c) Eleg09
SNR
Electrode (a)Eleg1n (b)Eleg01 (c)Eleg09
b

訊雜比
12.36
26.56
26.87
4. Results
• NI/LabWindows GUI
5.Conclusions and Future Work
More simulation and analysis of the
electrode
 Combined with Android

References
[1] Electrostatic Interference in Contactless Biopotential Measurements Óscas
Casas,2007
[2] Triboelectricity in Capacitive Biopotential Measurements , Tobias
Wartzek,2010
[3] Effective Coupling Impedance for Power Line Interference in CapacitiveCoupled ECG Measurement System, Ko Keun Kim and Kwang Suk Park, 2008
[4] The Stability Analysis of a Biopotential Measurement System Equipped
With Driven-Right-Leg and Shield-Driver Circuits , Emad Alnasser , 2014
[5] Common Mode Noise Cancellation for Electrically Non-Contact ECG
Measurement System on a Chair, Ko Keun Kim, 2005
[6] Thin and flexible active electrodes with shield for capacitive
electrocardiogram measurement, Seung Min Lee , 2010
Thank you for your
attention