SLEEP MONITOR
STRIP
Description
Features
Very low thickness,
imperceptible on mattress
High open-circuit voltage sensitivity to
dynamic strain
Can detect breathing, pulse
and body movement
Ballistocardiographic (BCG) principle
Applications
heart rate, heart rate variability, respiration
rate measurements
TE CONNECTIVITY SENSORS /// SLEEP MONITOR STRIP
The sleep monitor strip is a strip of Piezo film (piezoelectric PVDF polymer)
800mm long and 8mm wide. The active electrode area is 698.5mm long and 3mm
wide. The total thickness of the strip is around 50 microns, making it extremely
flexible and entirely imperceptible when placed under the body. Electrical
interconnection is made via two crimped solder tabs. The strip produces a charge
or voltage output when subjected to dynamic strain (change in length). When
mounted across a mattress in line with the chest/heart, the strip can detect heart
sounds, tiny changes in load or center of gravity due to breathing. These signals
may then be assessed over an extended time period (e.g. overnight) and may be
indicative of duration, phase, or quality of sleep.
The sensor requires no external power and is therefore suitable for use with
battery-operated equipment where power consumption must be kept to a minimum.
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SLEEP MONITOR STRIP
Typical properties
Parameter
Min
Typ
Max
Units/condions
Overall length
797.5
800.0
802.5
mm, excluding solder tabs
Overall width
7.7
8.0
8.3
mm
Active electrode length
691.5
698.5
701.0
mm
Active electrode width
2.7
3.0
3.3
mm
Capacitance
5.4
7.3
9.3
nF@1k Hz
Dissipation Factor
-
0.02
0.03
@1k Hz
Strain Sensitivity (V)
-
0.015
-
V/με
Strain Sensitivity (Q)
-
110
-
pC /με
Base film thickness
27
30
33
μm
Yield stress
45
-
-
MPa (stretch direction)
Typical response
(on top of mattress, under mattress protector)
0.1 Hz data
Q p-p
V p-p OC
Pulse
0.5-1 nC
75-150 mV
Breathing
2-7 nC
0.3-1 V
Movement
100-500 nC
10-70 V
Notes on typical response
Peak-to-peak charge (Qp-p) and voltage into open-circuit conditions (Vp-p OC) are shown as a very general guide only. Signal levels may
be affected by the compliance of mattress, thickness and material of bed linen, occupant's posture/ orientation on the bed, body shape,
physique and health, and many other factors.
Interface requirements
As with any piezoelectric sensor, the low frequency response of the sleep monitor strip is set by the external circuit to which the sensor is
connected. Under true open-circuit conditions, the leakage of charge through the piezo dielectric material
is minimal, and the low
frequency response extends close to DC (< 1m Hz). In practical terms, it is necessary to define
a functional limit to avoid long-term
drift and potential slow but high-amplitude signals resulting from the pyroelectric response of the film. Adult respiratory rate is generally
taken as falling in the range 12 to 18 breaths/minute, although this may reduce during sleep. To capture breathing signals, it is important to
use the sensor with an electronic network that has suitable low frequency response.
The Piezo film lab amplifier (TE Part # 1007214-X) offers a selectable lower limiting frequency of 0.1 Hz, which is useful in this case. In
addition, an upper limiting frequency of 10 Hz can be set, which eliminates unwanted 50/60 Hz mains (line) interference. A wide range of
overall gain is offered, and the Amp may be operated either in charge mode or in voltage mode.
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SLEEP MONITOR STRIP
Direct connection of the sleep monitor strip to a conventional oscilloscope input (with 1M input resistance) is not recommended, as this will
form a high-pass filter with cut-off frequency (to -3dB) at approximately 22 Hz. This will significantly attenuate the target signals arising from
breathing or pulse.
To obtain a response to 0.1 Hz (-3dB point) with a simple voltage-mode circuit, an input resistance of 220M is required.
If only heart rate is required (and not respiratory rate), then a lower limiting frequency in the range 1 – 3 Hz may be sufficient.
If an interface circuit is constructed that allows successful detection of pulse signals, then this is very likely to become saturated when gross
bodily movement occurs, with up to 500X higher signal level. If the circuit is also set up to detect breathing with a response down to 0.1 Hz,
then the effect of saturation and/or time constant settling may cause up to 30s interruption of detection of pulse & breathing after body
movement occurs.
Dimensions
TE CONNECTIVITY SENSORS /// SLEEP MONITOR STRIP
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SLEEP MONITOR STRIP
Additional Notes
TE Part
# 10184000-01
This product is offered as a low-cost short-term solution for evaluating the suitability of Piezo film for vital signs or sleep monitoring. The
sleep monitor strip is not sealed against moisture. Exposure to moisture may affect electrical performance of the sensor. The printed ink
electrodes have a thin protective coating but are not intended to provide full electrical insulation. The sensor element is not electrically
shielded, and the sensor and/or any interface electronics connected to it may be susceptible to RFI/EMI and/or electrostatic sensitivity.
Additional mechanical protection may be required for long- term use. TE Connectivity makes no warrant of performance or suitability for any
specific end use or application.
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EUROPE
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Measurement Specialties, Inc. A
TE Connectivity Company Phone:
+1 800-522-6752
Measurement Specialties (Europe), Ltd., A
TE Connectivity Company
Phone: +31 73-624-6999
Measurement Specialties (China), Ltd., A
TE Connectivity Company
Phone: +86 400-820-6015
Email: customercare.frmt@te.com
Email: customercare.dtmd@te.com
Email: customercare.shzn@te.com
TE.com/sensorsolutions
Measurement Specialties, Inc., a TE Connectivity company.
TE Connectivity, TE connectivity (logo) and EVERY CONNECTION COUNTS are trademarks. All other logos, products and/or company names referred to herein
might be trademarks of their respective owners.
The information given herein, including drawings, illustrations and schematics which are intended for illustration purposes only, is believed to be reliable.
However, TE Connectivity makes no warranties as to its accuracy or completeness and disclaims any liability in connection with its use. TE Connectivity's
obligations shall only be as set forth in TE Connectivity's Standard Terms and Conditions of Sale for this product and in no case will TE Connectivity be liable
for any incidental, indirect or consequential damages arising out of the sale, resale, use or misuse of the
product. Users of TE Connectivity products should make their own evaluation to determine the suitability of each such product for the specific
application.
© 2019 TE Connectivity Ltd. family of companies All Rights Reserved.
TE CONNECTIVITY SENSORS /// SLEEP MONITOR STRIP
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