BME100 f2015:Group3 1030amL3

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Name: Jennifer Le
Name: Noah Pollack
Name: Lauren Butler
Name: Shannon Grassi
Name: James Wood
Name: Carlos Garrido


Descriptive Statistics

Data for Heart Rate (BPM)
Data is in measurements of heart rate (BPM)

Data for Temperature (°F)
Data is in measurements of temperature (°F)


Data for Heart Rate (BPM)

Data for Temperature (°F)


Data for Temperature (°F)

Data for Heart Rate (BPM)


The readings from the Spree headband were compared against those from devices predetermined to give “gold standard” readings in body temperature and heart rate. The use of a paired t-test revealed whether the Spree headband differentiated from the gold standard in either of these two areas.

The comparison for the temperature readings yielded a P-value of 4.7*10^-77. This value revealed with nearly 100% certainty that there is a significant difference between the values recorded by the spree and the thermometer used as the gold standard. This implies that the Spree headband is flawed and returns inaccurate temperature readings. Furthermore, the Pearson’s r value revealed nearly no correlation between the two data sets.

When the T-test was performed on the data for heart rate, a value of .39 was recorded. Because this value was much greater than .05, the Spree could not be determined to be taking readings that significantly differed from that of the gold standard device. The Pearson’s r value was also close to 1, revealing a positive correlation between the data sets.

There are quite a few design flaws in the design of the Spree band. The placement of the sensor is an issue that affected the accuracy of the sensor. Having the device in the form of a headband allowed the temperature reading to be altered by the surroundings.

Another factor that affected the temperature readings was the sweat of the user. Since the temperature of the Spree band rose to higher recorded temperatures than the gold standard, the heat released in the sweat altered the readings. In addition, the temperature reading for the Spree band was given in a ranking order from 1 to 4 which is unclear, and not useful for the user.

Another possible design flaw is the device's method of acquiring readings through an app that connects the device to the user's phone through Bluetooth. Since the device is connected through Bluetooth, there arises issues such as pairing of the device to the phone, and profile mismatches.

Aesthetically the headwear was not pleasing to the eye, as it was clunky in the front part of the device. The device was uncomfortable and did not fit well on the user's head.

In order to get a more accurate and consistent reading for the device, the headband could instead be sensors located inside the ears where the reading of body temperature is not affected by the surroundings like the headband. Since the heat from sweat is an issue, using a sweat or water resistant would minimize the alteration of the temperature readings. In addition, the device could changed to give a direct reading on the device, instead of relying on the Bluetooth. This way there is no issue of profile matching, delayed readings, or device pairing.


Target Population and Need

The target population would be athletes, workers--ultimately anyone who would be exposed to conditions of dehydration. There are millions of diverse individuals who experience dehydration. For the target population, this allows individuals to measure dehydration before it becomes a health impairment. Dehydration would be measured by electrolytes. The population most ideal for this device would be those living in arid, hot, and dry areas as people living in these areas would be most susceptible to not realizing their dehydration or that they are not well-hydrated.

This is a need in our society since people often fail to realize their need to maintain an adequate level of hydration. This is especially true in athletes who push themselves as well as the elderly and children who have difficulty maintaining homeostasis. In very dry places, more often then not, people fail to realize that they are dehydrated because they are too occupied doing their day-to-day activities, such as work or schooling, and do not think to hydrate themselves adequately throughout the day as they should.

Device Design

The HydroBand is composed of synthetic fibers with sensory arrays that allow for the monitoring of electrolyte levels. This band ultimately determines how hydrated an individual is. Detection of electrolytes is usually found with blood tests. Our band instead is able to deduce electrolytes through simply being in contact with skin. The band will initially be colored white prior to reading the user's levels of hydration, and can later turn green, yellow, or red to indicate the user's level of hydration. Green being adequate hydration, yellow being less than adequate hydration, and red being critical need for hydration.

Hydroband Angled View

Hydroband Front View

Hydroband Top View

Hydroband Indicator Color Spectrum
Colors will range from Red, Yellow, Green.

Indicator Colors

  • Red: Spectrums of red indicates that the user is dangerously dehydrated and must immediately replenish their body with water.
  • Yellow: Spectrums of yellow indicates that the user is somewhat dehydrated.
  • Green: Spectrums of green indicates that the user is well-hydrated.

Hydroband sizes are available in sizes ranging from Child (S), Adult (M), and Large Adult (L) from 180mm to 210mm in total band length to better fit each individual user's wrist size.

Inferential Statistics

The HydroBand was used to test osmolality in 30 individuals to determine hydration. These same 30 individuals then had their blood drawn to test for osmolality as well. These readings were then compared to test the accuracy of the HydroBand. Because the Hydroband displays a color instead of an exact reading, each color was assigned an estimated value based upon its true value range.

When a t-test was run on this data a p-value of .447 was returned, failing to disprove the hypothesis that there is a significant difference between the readings taken from the HydroBand and those provided by the blood tests.

The Pearson's r-coefficient for this data set was very close to 1 (r = .914), further suggesting that there is a definite correlation between the measurements taken by the two devices.