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 electrode spacing and strap band dimensions may be selected to form a strap band that may accommodate a wide range of user body sizes for a target region the electrodes are positioned in contact with. The electrodes may be composite electrodes having multiple layers of conductive material in which an outermost layer is made from a material operative as an ion exchange layer. The ion exchange layer in contact with an electrolyte layer of a body portion may be operative to reduce motion artifact induced impedance and increase a signal to noise ratio for bio-impedance circuitry or other biometric circuitry coupled with the electrodes.
1 . A system, comprising:
a strap band including an encapsulated wire bus having a plurality of composite electrodes connected with the wire bus, the wire bus including wires, each wire connected with one of the plurality of composite electrodes,
each composite electrode including a substrate made from a first material and an ion exchange layer in contact with the substrate, the ion exchange layer made from a second material that is different than the first material;
a band;
fastening hardware coupled with the band and with the strap 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.
2 . The system of claim 1 , wherein the second material comprises a metal chloride, a metal carbide or a metal nitride.
3 . The system of claim 2 , wherein the metal chloride comprises silver chloride.
4 . The system of claim 2 , wherein the metal nitride comprises titanium nitride or chromium nitride.
5 . The system of claim 2 , wherein the metal carbide comprises titanium carbide.
6 . The system of claim 1 , wherein the ion exchange layer comprises a flexible material impregnated with or infused with the second material, and the second material is an electrically conductive material.
7 . The system of claim 1 and further comprising:
an inner layer of a third material positioned between and in contact with the substrate and the ion exchange layer, the third material is different than the first material and the second material, and the first material comprises an electrically non-conductive material.
8 . The system of claim 1 , wherein the third material comprises a metal or a metal alloy, the second material comprises a metal chloride, and the first material comprises a plastic.
9 . The system of claim 1 , wherein the first material comprises a metal or a metal alloy.
10 . The system of claim 1 , wherein the first material comprises stainless steel.
11 . The system of claim 1 , wherein the first material comprises titanium.
12 . The system of claim 1 , wherein one or more of the plurality of composite electrodes have ion exchange layers that made from different second materials.
13 . The system of claim 1 , wherein the circuitry electrically couples two or more of the plurality of composite electrodes to bio-impedance driver circuitry and couples another two or more of the plurality of composite electrodes to bio-impedance pickup circuitry.
14 . A device, comprising:
a strap band; and
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 two composite electrodes that are adjacent to each other, adjacent composite electrodes in the two pairs are spaced apart from each other by an identical distance, and innermost composite electrodes in each pair are spaced apart by a distance that is approximately one-third of a length of the strap band.
15 . The device of claim 14 , wherein the second material comprises a metal chloride, a metal carbide or a metal nitride.
16 . The device of claim 15 , wherein the metal chloride comprises silver chloride.
17 . The device of claim 15 , wherein the metal nitride comprises titanium nitride or chromium nitride.
18 . The device of claim 15 , wherein the metal carbide comprises titanium carbide.
19 . The device of claim 14 , wherein the ion exchange layer comprises a flexible material impregnated with or infused with the second material, and the second material is an electrically conductive material.
20 . The device of claim 14 and further comprising:
an inner layer of a third material positioned between and in contact with the substrate and the ion exchange layer, the third material is different than the first material and the second material, and the first material comprises an electrically non-conductive material.