1. A biodegradable sensor device for mesh networking applications, the device comprising:
a frame formed of biodegradable material;
a biodegradable battery;
an antenna;
an environmental event detector comprising biodegradable material responsive to a change in environmental conditions, and,
signal generating circuitry configured to be responsive to detecting an environmental event by broadcasting a signal to other sensor devices in a mesh network and also to re-broadcast signals received from other sensor devices in the mesh network.
2. The device of claim 1, wherein the biodegradable battery is affixed to one surface of the frame and the antenna is formed on an opposite surface of the frame.
3. The device of claim 1, wherein the frame is formed of a polylactic acid and resin mixture.
4. The device of claim 1, wherein the biodegradable battery is a flexible biodegradable lithium ion battery.
5. The device of claim 1, wherein the device is formed into a tubular structure of concentric tubular structures wherein the battery is formed to be a tubular structure affixed to an interior surface of the frame formed to be a tubular structure and the antenna is formed on an outer surface of the frame and the signal generating circuitry is formed on an outer surface of the antenna and the environmental event detector is formed on an outer surface of the signal generating circuitry.
6. The device of claim 1, wherein the environmental event detector comprises bifurcated concentric tubular structures separated by a chemically dissolvable biodegradable material.
7. The device of claim 1, wherein the environmental event detector comprises bifurcated concentric tubular structures separated by a biodegradable insulator and a temperature reactive biodegradable material coupled to an interior surface of an interior one of the bifurcated concentric tubular structures.
8. The device of claim 1, wherein the antenna is formed of silver filament.
9. The device of claim 1, wherein environmental event detector further comprises an emitter configured to emit a sonic signal, and a detector configured to detect a sonic signal.
10. A mesh network comprising a plurality of nodes, each node comprising a biodegradable sensor device comprising a frame formed of biodegradable material, a biodegradable battery, an antenna, an environmental event detector comprising biodegradable material responsive to a change in environmental conditions, and, signal generating circuitry configured to be responsive to detecting an environmental event by broadcasting a signal to other sensor devices in a mesh network and also to re-broadcast signals received from other sensor devices in the mesh network.
11. A method for monitoring material integrity in a mesh network of biodegradable sensor devices, the method comprising:
embedding a plurality of biodegradable sensor devices in a material, each of the biodegradable sensor devices comprising a frame formed of biodegradable material, a biodegradable battery, an antenna, an environmental event detector comprising biodegradable material responsive to a change in environmental conditions, and signal generating circuitry configured to be responsive to detecting an environmental event by broadcasting a signal to other sensor devices in a mesh network and also to re-broadcast signals received from other sensor devices in the mesh network;
emitting from the environmental event detector of each of the sensor devices in the material, a sonic signal at a specified frequency;
detecting a sonic signal in the environmental event detector of at least one of the sensor devices in the material;
determining a frequency of the detected sonic signal; and,
broadcasting an alert to others of the sensor devices in the mesh network in response to the determined frequency residing outside of an acceptable frequency range indicative of the integrity of the material.
12. The method of claim 11, wherein the material is concrete.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A cuff for measuring parameters of an appendage, including volume or change in volume of the appendage, comprising:
a hollow, rigid tube having an inner surface and opposed ends;
a bladder having an inner surface, an outer surface, and opposed ends, the ends of the bladder being sealed to the ends of the tube to create an enclosed internal volume between the inner surface of the bladder and the inner surface of the tube and an external volume defined by the outer surface of the bladder and surrounded by the internal volume, the bladder having a normal, relaxed state, in which the internal volume is filled with a fluid and a retracted state in which the fluid is evacuated from the internal volume; and
at least one emitter and a plurality of detectors arranged in a linear array, the emitter and the detectors being positioned within the enclosed internal volume of the bladder and the emitter being separated from the closest detector by a minimum separation distance, wherein the emitter emits light at a first wavelength through the bladder into an appendage located within the external volume defined by the outside surface of the bladder, and the detectors detect light at the first wavelength that is back-scattered from the appendage and transmitted through the bladder to the respective detector positioned within the enclosed internal volume of the bladder;
wherein the bladder has a sufficient wall thickness and is made from a single material tinted with pigments selected such that the bladder material will absorb the specific wavelengths of light emitted by the emitter to damp light piping laterally within the bladder from the emitter to each detector but also allow for sufficient transmission of light through the bladder into and out of the appendage to properly illuminate the tissue and to properly detect the light back-scattered from the appendage; and further
wherein the emitter and detectors are attached to the inner surface of the bladder, the cuff contains at least one stiffener rib placed along the inner surface of the bladder parallel to the longitudinal axis of the tube, and the plurality of emitters and detectors are embedded in the rib.
2. The cuff of claim 1, wherein the bladder is made from a material tinted with pigments selected such that the bladder material also will achieve attenuation such as to decrease the intensity of the piped light to below the governing SNR of each detector.
3. The cuff of claim 1 wherein the detectors are uniformly spaced from one another.
4. The cuff of claim 1 wherein the minimum separation distance between the emitter and each detector is no less than about four millimeters.
5. The cuff of claim 1 wherein the cuff comprises two emitters, the first emitter emitting light at substantially 660 nm and the second emitter emitting light at substantially 810 nm, and each of the uniformly spaced detectors detects light at both 660 nm and 810 nm.
6. The cuff of claim 1 wherein the bladder is tinted to dampen light piping within the bladder for light wavelengths between 600 nm and 900 nm.
7. The cuff of claim 1 wherein the bladder is made of rubber or silicon rubber and has a wall thickness of between 0.012 inches and 0.016 inches.
8. The cuff of claim 1 wherein the bladder material is also stretchable and resilient.
9. The cuff of claim 1 further comprising a port in fluid communication with the bladder for emptying the bladder to assume the retracted state and filling the bladder to assume the relaxed state, the enclosed internal volume otherwise being sealed.