Abstract:
Absolute body temperature measurement is not easy to obtain. The temperature probe has to be placed in body cavities or swallowed to get core body temperature. The skin temperature usually has no relation to core temperature making it impossible to use in wearable devices. The present invention measures body temperature differences to monitor body temperature changes due to fever to generate alarms if needed. The invention is also useful in monitoring body temperature change due to exercise, that can be used to calculate the calories burned during the exercise session, activity and sleep.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Not Applicable 
       FEDERALLY SPONSORED RESEARCH  
       [0002]    Not Applicable 
       SEQUENCE LISTING OR PROGRAM  
       [0003]    Not Applicable 
       FIELD OF THE INVENTION 
       [0004]    The invention relates to the field of wearable sensor devices attached to an animal, including human, body and signaling certain conditions for detection by observers like humans or a camera integrated computer such as in a contemporary ‘smartphone’. 
       BACKGROUND OF THE INVENTION 
       [0005]    The monitoring of fever episodes is the main use of the current invention. To get core body temperature is very difficult unless you use a probe that is inserted to body cavities. This is good if you only need to monitor temperature once in a while. There are temperature changing stickers that you can use. It is not all that accurate and you need to keep watching it to know what is going on and visibility is poor at night. Skin temperature is usually dependent on sweating, air temperature, body temperature, blood circulation, body extremities and other parameters. So typical sensors on skin is not a good indicator of core body temperature. 
         [0006]    Body temperature rise from exertion is not normally taken care of in a normal electronic or chemical temperature sensors. This adds another layer of error in the reading. 
         [0007]    Typical electronic monitoring thermometers suffer from battery capacity when transmitting temperature continuously over wireless networks making them bulky or having to recharge them often. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The apparatus and method disclosed is based on the idea of detecting temperature changes and not absolute temperature. This allows the use of skin temperature as a gauge for core temperature variation. This can be used to generate alarms in certain situations. For example, your child is still sick with 102 degree F. (measured with a body cavity thermometer) viral fever at 10 pm. You just gave him fever-reducing medicine. You do not typically know if the child&#39;s fever is still high or lower from that time to the time for next dose which is typically 4-6 hours from 10 pm. The only way around it is you do not sleep, wake the child up from time to time and measure temperature. If the temperature is still rising, you need to give him medication earlier, apply cold head patches or even take the child to emergency hospital to prevent brain damage. 
         [0009]    To allow for skin temperature variation to be used as a proxy for core body temperature, it needs to be used in the head, chest or back areas. Care is taken to isolate the sensor from the environment and trap the heat in an air pocket where the sensor is situated. It is also based on the idea that the sensor is in the form of an adhesive patch that attaches to the body, is removable and re-usable after adhesive change. An accelerometer is used to detect activity and correct for temperature errors due to exertion. The battery can also be replaced when needed. The temperature change is also communicated to observers, human or computer with camera, by LED&#39;s and Audio output. This allows the observer to see the LED status or hear the alarm sounds depending on temperature change magnitude. 
         [0010]    A software running on a contemporary smartphone with a camera is able to detect the change in LED colors and rate of flashing to determine temperature change. This may also be achieved using audio signaling or light signaling. These methods can be used to send temperature and acceleration data to the smartphone software. The software on the smartphone can then call another phone or ring out the alarm or send messages. Another way to send data is using the 3-wire serial port on the sensor patch. This is used to physically be connected to the Bluetooth adapter to transfer data logged in the sensor patch non-volatile memory to the smartphone. 
         [0011]    The accelerometer on the sensor patch can be used as a standalone activity tracker too. Since the sensor patch can be used on the back or chest, they can be easily used as a better sleep detector than the ones on the market that needs lot of data processing to determine sleep condition or pressing a button when you go to sleep. Similarly the sensor patch on the thigh can detect and track sitting detection very well to provide sitting monitoring as this effects the health a lot. This is not available in wrist worn devices like Jawbone wrist band or Mobile phone activity sensor. A typical wrist based sensor like the one described in prior art, Fitbit US Patent Application Publication Pub. No. US2014/0088922A1, the acceleration sensor is worn on the wrist and does not have any unique axis at or near full scale acceleration due to gravity in sleeping or sitting or walking movements. Consequently you need user input to signal sleep or significant processing algorithm to detect activities. This leads to often incorrect data. The sensor patch provides a way to position itself for optimum activity detection. 
         [0012]    In summary these are the unique parts of this invention: 
         [0013]    a unique temperature difference based fever monitoring and alarm; 
         [0014]    a unique positioning and sealing of the flexible temperature sensor package and the skin area related; 
         [0015]    re-usable sensor package with adhesive pad change and coin cell change; 
         [0016]    the sensor package can be attached to different parts of the body for appropriate activity detection. Attach to calf for running detection for example; 
         [0017]    accelerometer based temperature correction for activity related temperature rise; 
         [0018]    calorie expenditure calculation during exercise; 
         [0019]    direct visibility of LED warning signals and audio alarm; 
         [0020]    ideal fever and antipyretic medicine temperature cycle monitoring; extended battery life due to deep sleep mode and lack of a bluetooth or radio wireless device on board; 
         [0021]    unique powered bluetooth module with its own power and connected to sensor package only when data is download without reducing sensor battery life; 
         [0022]    unique software to pair to a computer such as contemporary smartphone using LED color signaling. The software can also work with existing non-electronic temperature sensor strips that change color with temperature; 
         [0023]    unique software to pair to a computer such as contemporary smartphone using audio FSK signaling. 
         [0024]    ability to track basal temperature in the morning just before waking up to monitor conditions like hyperthyroidism based on accelerometer sleep detection and temperature change data logged to memory. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0025]      FIG. 1A  shows internals of one embodiment of the invention, where  100  is the sensor package that can be attached to the human body or clothing.  110  is the acceleration and gyroscopic sensor integrated circuit packages.  120  is a temperature sensor that sends the temperature of the sensor as an analog voltage output to the analog to digital converter (ADC) of the microcontroller  130  for temperature measurement.  140  represent power source, which in this embodiment is a 3v coin cell.  150  is the Non-Volatile data storage area and  160  the software area within the microcontroller  130 .  170  is an audio output buzzer.  180  is the array of color LED&#39;s. Both the LED&#39;s  180  and buzzer  170  are used to signal temperature conditions and data communication with smartphones. 
           [0026]    The  FIGS. 1B , IC and  10  shows different places on the body where the temperature sensor package  100  may be placed. Position in  FIG. 1D  is suitable only for monitoring how much sitting and actual walk the user gets. 
           [0027]      FIG. 2A  shows the top view of an embodiment of the complete sensor package. Item  200  is the coin cell holder. Item  210  is the mechanical switch.  220  represents the color LED array.  230  represents the microcontroller.  240  shows the buzzer. 
           [0028]      FIG. 2B  shows the side view of the sensor package.  280  shows the transparent RTV filled area.  290  shows the pcb assembly.  270  shows the disposable adhesive layer that can be replaced for re-use of the rest of the package 
           [0029]      FIG. 2C  shows the bottom side of the sensor package.  250  shows the temperature sensor position and  260  shows the air pocket it forms with the skin to preserve heat for the temperature sensor.  270  shows the disposable adhesive layer that can be replaced for re-use of the rest of the package 
           [0030]      FIG. 3  shows the use of a bluetooth adapter  304  to collect stored data from the sensor  300  detached from the body and its copper strip edge  302  is inserted to the connector  303  on the adapter  304 . Switch  301  is used in a timed hold down to start data download. The data is put out by the sensor  300  through its serial port in  302  and the adapter  304  transmits that data wirelessly to a computer device  305  it is authorized to connect to. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    While the making and using of various embodiments of the present disclosure are discussed in detail below, it should be appreciated that the present disclosure provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The disclosure is primarily described and illustrated hereinafter in conjunction with various embodiments of the presently-described systems and methods. The specific embodiments discussed herein are, however, merely illustrative of specific ways to make and use the disclosure and do not limit the scope of the disclosure. 
         [0032]    Conceptual block diagram in  FIG. 1A  shows one embodiment of the internals of the sensor package. It has a temperature sensor Integrated circuit (IC)  120  that works well in the temperature range of animal body temperature range. It also has an accelerometer IC with 3 axis sensing and a gyroscope for rotation sensing  110 . A low-cost microcontroller  130  is the heart of the system. It has reserved some space in the flash memory for non-volatile memory  150 . Some of the memory is used by the software (firmware)  160  instead. There are three LED&#39;s  180  in this embodiment, green, red and yellow. There is also a  170  buzzer on the board.  FIG. 2A  show flexible printed circuit assembly top view, an embodiment of the invention as built for test.  FIG. 2B  shows a side view of the sensor package assembly of  FIG. 2A .  FIG. 2C  shows the bottom side of the sensor package of  FIG. 2A . 
         [0033]    The microcontroller  230  puts the sensor assembly of  FIG. 2A  to deep sleep most of the time. When the user pushes the switch key  210 , the microcontroller  230  is interrupted and wakes up and monitors the switch press count with a periodicity of 200 mS. If the switch continues to be pressed and then released during a majority of 10 such 200 mS interrupts, a ‘turn on’ condition is detected. Typically the user would place the sensor package on a kid&#39;s forehead and then ‘turn ‘on’ the sensor. Similarly this 200 mS timer is used to detect 5 s and 10 second button presses. The 10 second key press  210  is seen as a signal to upload data from the sensor package of  FIG. 2A . A  5  second key press  210  and release is seen as deep sleep condition with long battery life in lieu of actual turn off of the device. 
         [0034]    As soon as it is ‘turned on’, the microcontroller  230  reads the temperature from sensor  250  as analog data input on the microcontroller  230  analog input. The microcontroller  230  wakes up on a periodic timer every minute and takes a reading for the next 5 minutes. The average of these 5 reading is taken as a ‘reference temperature’ reading and is stored in flash data memory as such. The microcontroller  230  then enters its deep sleep mode to save power. 
         [0035]    Once ‘reference temperature’ is taken, the microcontroller  230  wakes up every minute. The microcontroller  230  acquires a new temperature reading. The default yellow LED  180  flashes at 1 Hz rate a couple of times. This reading is compared against the reference every single time this happens. In this embodiment the temperature change limits are considered ±0.25° C., ±0.50° C., ±0.75° C. and ±1.00° C. 
         [0036]    If the [new temperature−reference temperature&gt;0 and within ±0.25° C.] the yellow LED  180  flashes at 2 Hz a couple of times. 
         [0037]    If the [new temperature−reference temperature&gt;0.25° C. and &lt;0.50° C.] the red LED  180  flashes at 1 Hz a couple of times. 
         [0038]    If the [new temperature−reference temperature&gt;0.50° C. and &lt;0.75° C.] the red LED flashes at 2 Hz a couple of times. 
         [0039]    If the [new temperature−reference temperature&gt;0.75° C.] the red LED flashes at 3 Hz a couple of times. The buzzer is turned on for 15 seconds. 
         [0040]    If the [new temperature−reference temperature&lt;−0.25 and &gt;−0.50] the green LED  180  flashes at 1 Hz rate. 
         [0041]    If the [new temperature−reference temperature&lt;−0.50] the green LED flashes at 2 Hz rate. 
         [0000]    The microcontroller  230  also reads the position of the four accelerometer  110  axes using an I2C interface. The microcontroller  230  stores the data current temperature and accelerometer data in the microcontroller non-volatile data memory. 
         [0042]    As described in section [0018] an upload signal from key  210  press of 10 seconds starts the download operation. The sensor package basically transmits the reference temperature data, temperature and accelerometer data paired according to the order they were saved in the non-volatile memory. This signal is transmitted via the UART Rx, Tx and Gnd lines as shown in connector  302  of  FIG. 3 . The UART to bluetooth adapter  304  has a connector  303  that will accept the sensor package  301 , connector  302 . 
         [0043]    In another embodiment of the invention, there is no need for a bluetooth adapter to transfer data to a computer device  305 . The software running on the sensor package codes the data to be transmitted during temperature and accelerometer data collection timer events or during upload of entire logged data, into color coded LED colors. The number of bits in each word will depend on the number of LED&#39;s  180  available on the device. The color coded data is set on the LED&#39;s for a word for a 20 mS, then blanked for the next 13 mS. Then the next word to be transmitted is loaded to the LED&#39;s  180  and the process continues till all data is sent. The software running on  305  wakes up when the sensor package LED&#39;s are ready to be sent, except the for the first time when the camera and software on the computer device has to be on all the time. Other times, these parts can be sent to low power mode. The said software then opens the camera and captures images at a rate of 30 fps. The images are processed with opencv computer vision library to detect edges of the boundaries (contour) of individual LED&#39;s. Then each of the contour area is checked for validity to LED contour sizes and typical LED contour shapes. Then the color of each contour is determined using opencv library functions. Once a whole frame is processed we have reconstructed a word. This is written to a file and the frame is discarded to save memory. This is continued to the end of the data and the said file on device  305  will now have the data transmitted from the sensor package  300  to the computer device  305 . The same image processing technique is used to generate alarms and calls to other phones in case of a particular alarm temperature condition. The above described technique is particularly attractive when sending small amounts of data wirelessly. 
         [0044]    In another embodiment, the software running on a computing device  305  like a smartphone or tablet or a computer device can use its camera or USB camera to detect non-electronic type temperature color-changing stickers and their color change to generate alarms or calls to alert parents. 
         [0045]    In another embodiment of the invention the data transfer between the sensor package  300  and the computer device is through the buzzer audio output. The data to be transmitted from sensor package  300  is coded in frequency shift keying (FSK)modulation and the software running on the smartphone  305  constantly computes the FFT or Goertzel algorithm to detect the signal frequency coming in and converts the bit frames to data. The data is used for further processing for alarm generation or calorie expenditure calculation or activity monitoring. 
         [0046]    Once the computer  305  has uploaded the accelerometer data and temperature data it can correct for body temperature rise due to fever from error due to body temperature rise due to activity. The calorie expenditure is calculated from the temperature difference before exercise and temperature measured after exercise and local environmental temperature from weather server. The acceleration data is used to determine activity and position to determine the correctness of temperature based measurement. The duration and intensity of the activity from accelerometer data is used to calculate approximate calorie expenditure during the period.