# An IoT-Based Glucose Monitoring Algorithm to Prevent Diabetes Complications
## 2 Related Work  
Platforms for wireless monitoring of glucose levels seek to optimize communication and the inclusion of different types of noninvasive sensors. This section describes the main proposals found in the literature review. Noninvasive techniques that measure glucose look for variables that substitute blood as the main element, the aim is also to make the system portable for the patient. One of the first efforts was based on the principle of detecting the change in fluorescence resonance energy transfer efficiency of a protein synthesized as a function of analyte concentration [9]. Technologies such as GSM (global system for mobile communications) have been used in glucose monitoring. Different varieties of noninvasive sensors have been proposed to perform the sensing function. An arrangement of nanowires made of ZnO (zinc oxide) and an infrared emitter diode made of GaAs are examples of this category [10; 11]. The effortsof the research community are not limited to keeping track of glucose levels. Additional parameters have been added to form a comprehensive system. In [12], besides glucose levels, cardiac-type diseases have been contemplated. Furthermore, communication is improved through the use of Zigbee, and display characteristics of the readings are added. Real-time communication and low power consumption make WSNs (wireless sensor networks) an attractive technology for monitoring techniques. The integration of a WSN in conjunction with a minimally invasive sensor allows for portability and size reduction. With this application, the sensor is placed in the layer of the body's subcutaneous tissue to determine the amount of oxygen and, as a function of this, the glucose level [13]. Portability is an important factor when we are following up on elderly people. The noninvasive sensors attached to a miniature electronic mechanism allow for better follow up [14]. Sensors of the chronoamperometric type and ASIC (application-specific integrated circuit) designs make up a small battery-free device [15]. Smartphones and the characteristics of their operating system can be utilized for the connection and visualization tasks. The Android OS can be easily adapted to carry out the functions. Invasive and noninvasive sensors can be used for communication with a mobile device. In this way, patients themselves can monitor the readings. Moreover, the results can be sent to the cloud so that they can be viewed anywhere by a patient's doctor and relatives. Noninvasive sensors are still an area of opportunity, and therefore researchers continue to look for alternative designs that are more suitable for patients [16]. In [17], the authors proposed a design that employees an ion-sensitive field-effect transistor which is connected to a microcontroller. The readings are sent to a doctor through a Wi-Fi module. Further research is required to overcome the limitation of the sensor being exposed to contamination. The sending of glucose estimations has been optimized using a wireless body area network (WBAN) [18]. To verify it, the authors used a commercial sensor and communication via Zigbee. Additionally, the system stored the data in a desktop-based application. In this way, the information was available to the doctor, nurse, and a patient's relatives. To achieve better precision in the readings, modifications to the traditional invasive glucose reader are possible. The amount of gluconic acid detected by the sensor produces a current that is converted to voltage, and this variable is processed by a microcontroller to show the glucose value [19]. Architectures based on the IoT have attracted the attention of researchers in recent years [20]. They make use of standardized technologies to monitor glucose levels, as well as body temperature. With this kind of architecture, it is possible to have readings in real time and to store the information in back-end type servers [21]. A patient's caregivers can track his or her evolution from their mobile device or by accessing a web page.