SLEEP MONITOR STRIP Description Features The sleep monitor strip is a strip of Piezo film (piezoelectric PVDF polymer) Very low thickness, 800mm long and 8mm wide. The active electrode area is 698.5mm long and 3mm imperceptible on mattress wide. The total thickness of the strip is around 50 microns, making it extremely flexible and entirely imperceptible when placed under the body. Electrical High open-circuit voltage sensitivity to interconnection is made via two crimped solder tabs. The strip produces a charge dynamic strain or voltage output when subjected to dynamic strain (change in length). When Can detect breathing, pulse mounted across a mattress in line with the chest/heart, the strip can detect heart and body movement 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 Ballistocardiographic (BCG) principle indicative of duration, phase, or quality of sleep. The sensor requires no external power and is therefore suitable for use with Applications battery-operated equipment where power consumption must be kept to a minimum. heart rate, heart rate variability, respiration rate measurements TE CONNECTIVITY SENSORS /// SLEEP MONITOR STRIP 06/2019 PAGE 1 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/ Strain Sensitivity (Q) - 110 - pC / Base film thickness 27 30 33 m 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. TE CONNECTIVITY SENSORS /// SLEEP MONITOR STRIP 06/2019 PAGE 2