Personal hydration monitor
Disclosed are various embodiments for a flexible hydration sensor that can be implemented in a wearable device. A hydration monitoring device can include at least one flexible electrode comprising a plurality of silver nanowires embedded within a polydimethylsiloxane (PDMS) substrate. Processing circuitry can be configured to measure a hydration level of an individual wearing the hydration monitoring device based at least in part on a measurement of a skin impedance of the individual. In some embodiments, the hydration monitoring device can also generate a hydration metric based on the level of hydration and display the hydration metric.
1. A monitoring device, comprising:
a flexible electrode configured to conform with a surface of skin, the flexible electrode comprising nanowires or nanoparticles embedded within a polydimethylsiloxane (PDMS) substrate and presenting a complex impedance when positioned in contact with skin;
a housing configured to be positioned against the surface of skin with a band that secures the flexible electrode in position on the surface of skin, wherein the band comprises a wristband, an armband, a chest strap, or a headband; and
processing circuitry positioned within the housing, the processing circuitry being communicatively coupled to the flexible electrode and configured to:
present an excitation frequency to the complex impedance of the flexible electrode;
sample a response of the complex impedance to the excitation frequency; and
measure a level of hydration using the flexible electrode based on the response.
2. The monitoring device of claim 1 , wherein the flexible electrode comprises silver nanowires or nanoparticles embedded within the PDMS substrate.
3. The monitoring device of claim 1 , wherein the flexible electrode comprises at least two interdigitated silver nanowire electrodes that are electrically isolated from each other in a common layer of the PDMS substrate.
4. The monitoring device of claim 1 , wherein the processing circuitry comprises impedance converter network analyzer circuitry.
5. The monitoring device of claim 4 , further comprising a battery operable to power the processing circuitry.
6. The monitoring device of claim 1 , wherein the processing circuitry is further configured to generate a hydration metric based on the level of hydration.
7. The monitoring device of claim 6 , further comprising a display device configured to display the hydration metric.
8. The monitoring device of claim 6 , further comprising a communication module configured to communicate the hydration metric to an external device.
9. The monitoring device of claim 1 , wherein the flexible electrode is adapted for contact with skin.
10. The monitoring device of claim 1 , within a smartwatch, a fitness band, or a patch.
11. A method, comprising:
positioning a housing comprising a flexible electrode against a surface of skin, the flexible electrode positioned on a bottom side of the housing in contact with the skin;
presenting, by processing circuitry, an excitation frequency to a complex impedance of the flexible electrode;
sampling, by the processing circuitry, a response of the complex impedance to the excitation frequency; and
measuring, by the processing circuitry, a level of hydration based on the response, wherein the flexible electrode is configured to conform with the surface of skin, comprises nanowires or nanoparticles embedded within a polydimethylsiloxane (PDMS) substrate, and presents the complex impedance when positioned in contact with skin.
12. The method of claim 11 , wherein the flexible electrode comprises silver nanowires or nanoparticles embedded within the PDMS substrate.
13. The method of claim 11 , wherein the excitation frequency is in the range of about 10-100 kHz.
14. The method of claim 11 , further comprising displaying the level of hydration on a display device.
15. A monitoring device, comprising:
a flexible electrode configured to conform with a surface of skin, the flexible electrode comprising at least two interdigitated silver nanowire or nanoparticle electrodes in a substrate comprising a polydimethylsiloxane (PDMS) substrate and presenting a complex impedance when positioned in contact with skin, the at least two interdigitated silver nanowire or nanoparticle electrodes being electrically isolated from each other in a common layer of the PDMS substrate; and
processing circuitry configured to measure a level of hydration using the flexible electrode.
16. The monitoring device of claim 15 , wherein the processing circuitry is configured to:
present an excitation frequency to the complex impedance of the flexible electrode;
sample a response of the complex impedance to the excitation frequency; and
measure the level of hydration based on the response.
17. The monitoring device of claim 15 , wherein the processing circuitry comprises impedance converter network analyzer circuitry.
18. The monitoring device of claim 15 , further comprising a battery operable to power the processing circuitry.
19. The monitoring device of claim 15 , wherein the processing circuitry is further configured to generate a hydration metric based on the level of hydration.
20. The monitoring device of claim 19 , further comprising a display device configured to display the hydration metric.