Our design set out to meet all of the design criteria we said before.

We firstly had to go into the noninvasive method of getting the glucose levels. This led to our research in using interstitial fluid, which is a method being used today. The closest model to ours was the Dexcom G6, which still uses invasive techniques to get the sweat. After searching for alternate solutions, we stumbled upon wrinkled, stretchable, nanofiber (WSNF)[7] sensors that use these electrodes that react with the sweat glucose and are able to interpret the reaction as a current, which sends a reading with glucose levels. We utilized this sensor and modified it to work with our device.

However, this was just the first step towards noninvasiveness. The second problem was that sweat is not as readily available as blood. Even the Dexcom G6 uses invades the skin minimally to get to those sweat glands. Our solution first started with us figuring out how our device will even connect to the patient. After some thought, a suction cup would be a viable option. Not only would this let the device connect to the patient, it actually causes the patient to sweat in that area trapped by the suction cup. That’s when we decided to put the sensor here with the suction cup. However, we did not want to rely on the suction cup only, so we also decided to put a LED light here. This LED light would work in conjunction with the suction cup to inhibit more sweating. The light would be a blue light due to it being the hottest color, which was found during research.[8] All three of these devices would work together and be on the bottom of the device exposed.

The next part came to working on the brains of the device. With some knowledge of electronics, we chose parts that would definitely be needed for the device. Firstly, we wanted our device to be rechargeable, so we decided on a Mini-B USB port as we were familiar with the charging port to charge devices like our calculators and old Nintendo DS’s, which had long battery lives, unlike the batteries in our phones. This port would then be able to serve as both a charging port and a direct connection to someone’s phone. This then led to what batteries would be used. It was common knowledge to us that lithium batteries are the best type for rechargeable batteries, so we chose to use two 3.7V Lithium-Ion Batteries as these were the smallest sized batteries we could find. The decision for these parts was to serve the purpose of a smaller and more discrete design. We then chose controllers for both the battery and the sensor. The battery controller is meant to manage where the power is delegated to throughout the device, whether it be the sensor or LED. Then the sensor controllers allow us to get the information from the WSNF sensor. These would then need to have some type of motherboard to work off of, so an evaluation board was also needed. We chose an evaluation board that works with sensors specifically. Then after this was found, we of course needed to find a Bluetooth chip as the device needs to connect over Bluetooth. We found a Bluetooth 5.0 chip that would definitely fit on the evaluation board. Then, these devices were all modeled in AutoCAD, which are the images being shown. Each device had a blueprint with annotations so it was easy to get a basic model out of the blueprints. These devices were then combined together and an outer cylindrical shell was made long with a lid. The suction cup would be attached to the bottom and the sensor, LED light, and Mini-B USB port would be sticking out. Those parts were cut out from the outer shell. The lid also had a circle cut out for the power button, which would also be used by the Bluetooth feature. With the shells made, HFPE plastic was determined as the material the shell and lid would be made out of due to its chemical and abrasion resistance. With the price known for all of the parts, the price of HFPE per cubic centimeter, and the price of rubber per cubic centimeter for the suction cup, the price for everything turned out to be $48.36. With a 300% mark up, the price on the market if we were to sell this would be $145.08. This price does not include the sensor since it was unclear how much it would cost to make, so it was left out. If we account for other components not considered, then it would be at most $200. This is for the whole package, while the Dexcom G6 is 169.99 for just the smallest package. There would of course be costs for most sensors, however, this should not be an issue anymore since these sensors should not cost too much as students were able to make the WSNF patch and if the tech is improved upon, it can be made much cheaper. These sensors may not last as long, but they for sure hurt way less than the invasive sensors common with most CGMs. In the end, we thought we came up with a really good design that met most of the design criteria and is able to be altered with ease as more innovations and experience comes over the years. The final design all together can be seen below.

 

 

 

 

 

 

 

 

These are links to the parts that were used. These were found on Digi-Key

• LED Light: https://www.digikey.com/en/products/detail/jkl-components-corp/LE-0603-04B/1885023
• Lithium Battery: https://www.digikey.com/en/products/detail/sparkfun-electronics/PRT-13851/6605199
• Bluetooth 5.0 Microchip: https://www.digikey.com/en/products/detail/murata-electronics/LBEE59B1LV-278/10129246
• Evaluation Board: https://www.digikey.com/en/products/detail/adafruit-industries-llc/904/5353628
• Sensor Controller System: https://www.digikey.com/en/products/detail/allegro-microsystems/ACS711KEXLT-15AB-T/3868194
• Battery Controller: https://www.digikey.com/en/products/detail/microchip-technology/MCP73811T-420I-OT/1626617?s=N4IgTCBcDaILIGEAKB2AzADgIxZAXQF8g
• Mini-B USB Port: https://www.digikey.com/en/products/detail/edac-inc/690-005-299-043/4312191

Connor Oh and Maher Bou Zeineddine