STRAP BAND FOR A WEARABLE DEVICE
A strap band including a flexible wire bus having electrodes and wires coupled with the electrodes is described. The strap band may be coupled with a device that includes circuitry configured to drive signals on some of the electrodes and receive signals from non-driven electrodes. The signal frequency applied to driven electrodes may be varied to increase/decrease signal penetration depth to sense different body structures positioned at different depths in the body portion. Different frequencies for different types of measurements may be selected to optimize sensing of bio-impedance, galvanic skin response, hear rate, respiration, heart rate variability, hydration, inflammation, stress, and arousal in sympathetic nervous system. A system clock frequency may be one of the frequencies used. A magnitude of the drive signal, a gain on the received signal or both, may be adjusted based on the frequency selected and/or to sense signals from the body structure(s) of interest.
1 . A system, comprising:
a strap band including an encapsulated wire bus having a plurality of electrodes connected with the wire bus, the wire bus including wires, each wire connected with one of the plurality of electrodes, wherein the plurality of electrodes includes drive electrodes and pickup electrodes,
a band; and
a device including circuitry coupled with the wires, the band and the strap band coupled to the device at opposing ends of the device,
the circuitry including a processor in communication with a control unit, the control unit including a bio-impedance unit coupled with a variable frequency signal and with the wire bus,
the bio-impedance unit coupled with a tissue depth signal configured to select a frequency for the variable frequency signal, the variable frequency signal coupled with the wire of at least one of the drive electrodes, and
the tissue depth signal determined by a biometric measurement type.
2 . The system of claim 1 , wherein the biometric measurement type comprises a bio-impedance measurement.
3 . The system of claim 1 , wherein the biometric measurement type comprises a galvanic skin response measurement.
4 . The system of claim 1 , wherein the biometric measurement type comprises a heart rate measurement.
5 . The system of claim 1 , wherein the biometric measurement type comprises a respiration rate measurement.
6 . The system of claim 1 , wherein the biometric measurement type comprises a selected one of mood, arousal of the sympathetic nervous system, hydration, or stress.
7 . The system of claim 1 , wherein the tissue depth signal is operative to set a magnitude of a drive signal applied to the wire of one or more of the drive electrodes.
8 . The system of claim 7 , wherein the drive signal comprises a current sourced by an amplifier circuit.
9 . The system of claim 1 , wherein the bio-impedance unit is coupled with a gain signal configured to select a gain for a pickup amplifier coupled with the wire of one of the pickup electrodes.
10 . The system of claim 9 , wherein a magnitude of the gain signal is determined by the biometric measurement type.
11 . The system of claim 1 , wherein at least one of the electrodes comprises a composite electrode.
12 . The system of claim 1 , wherein the frequency for the variable frequency signal is derived from a system clock.
13 . A device, comprising:
a strap band;
a wire bus encapsulated in the strap band and including a plurality of composite electrodes, each composite electrode coupled with a wire, each composite electrode including a substrate made from a first material and an ion exchange layer electrically coupled with the substrate, the ion exchange layer made from a second material that is different than the first material,
the plurality of composite electrodes are grouped into two pairs with each pair including a drive composite electrode adjacent to a pickup composite electrode that are spaced apart from each other by an identical distance, and innermost pickup composite electrodes in each pair are spaced apart by a distance that is approximately one-third of a length of the strap band; and
circuitry coupled with each wire, the circuitry including a processor in communication with a control unit, the control unit including a bio-impedance unit coupled with a variable frequency signal and with each wire,
the bio-impedance unit coupled with a tissue depth signal configured to select a frequency for the variable frequency signal, the variable frequency signal coupled with the wire of at least one of the drive composite electrodes, and
the tissue depth signal determined by a biometric measurement type.
14 . The device of claim 13 , wherein the biometric measurement type comprises a bio-impedance measurement.
15 . The device of claim 13 , wherein the biometric measurement type comprises a galvanic skin response measurement.
16 . The device of claim 13 , wherein the biometric measurement type comprises a heart rate measurement.
17 . The device of claim 13 , wherein the biometric measurement type comprises a respiration rate measurement.
18 . The device of claim 13 , wherein the biometric measurement type comprises a selected one of mood, arousal of the sympathetic nervous system, hydration, or stress.
19 . The device of claim 13 , wherein the bio-impedance unit is coupled with a gain signal configured to select a gain for a pickup amplifier coupled with the wire of one of the pickup composite electrodes.
20 . The device of claim 13 , wherein the frequency for the variable frequency signal is derived from a system clock.