Monitoring the use of personal protective equipment using a mobile application

V magistrskem delu smo predstavili sistem za spremljanje in opozarjanje na uporabo osebne varovalne opreme (OVO), ki deluje mobilno na osnovi aplikacije na mobilnem telefonu. V sklopu eksperimentalnega dela smo namreč razvili mobilno aplikacijo, ki ob vstopu v območje znane nevarnosti ali v območje, na katerem se zahteva specifična osebna varovalna oprema, uporabnika nemudoma obvesti o zahtevani OVO. Mobilna aplikacija ob tem tudi izpiše seznam zahtevane opreme na tem območju in pričakuje uporabnikovo potrditev njene uporabo. Za zaznavanje in potrditev dejanske uporabe neke opreme smo uporabili čip NFC, ki smo ga namestili na vsak posamezen kos OVO. Razvoj mobilne aplikacije je potekal v integriranem razvojnem okolju Android Studio z uporabo programskega jezika Kotlin. Spremljanje lokacije uporabnika v realnem času je bilo ključnega pomena za pravilno delovanje mobilne aplikacije. Poleg mobilnega telefona smo za to potrebovali še vsaj tri oddajnike bluetooth, s pomočjo katerih smo glede na zaznano jakost njihovega signala na mobilni napravi določili oddaljenost uporabnika od posameznega bluetooth oddajnika in posledično njegovo lokacijo v prostoru. V zvezi s tem smo izvedli tudi konkretne meritve upada moči signala z oddaljenostjo od posameznega oddajnika. Pri tem smo določili tudi ustrezno funkcijo, s pomočjo katere lahko glede na zaznano jakost signala izračunamo ogovarjajočo razdaljo. Ker smo pri meritvah jakosti signala ugotovili večja merska odstopanja smo pri analizi podatkov uporabili tudi t.i. Kalmanov filter. Lokacijo uporabnika v prostoru smo določili glede na oddaljenost od pozicij oddajnikov bluetooth s pomočjo metode trilateracije.In this work, we present a system for monitoring, notifying and identifying the use of personal protective equipment (PPE) using a mobile phone application. To this end, we have developed such mobile application that notifies the user of the required use of PPE when the user enters a known hazardous area or an area where specific equipment is required. The application notifies the user of the required equipment in the form of a digital checklist where the user can mark the requirements as complete. The development was done in the Android Studio programming environment using the Kotlin programming language. To confirm the actual use of personal protective equipment, we used NFC tags attached to each piece of PPE. To indicate the appropriate requirements, we introduced user location tracking. This feature is one of the most important functions of our application. The hardware requirements for this feature consisted of a smartphone and at least three Bluetooth beacons. The distance of the user to each of the beacons was determined based on the received signal strength. Using this metric, we were also able to determine the user’s location. In this context, we measured the decrease in signal strength with increasing distance from the transmitter. In this way, we established an equation that calculates the distance based on the received signal strength. Since we observed a major problem with large variations in our measurements, we filtered the input data by applying the Kalman filter. We determined the location of the user in the room based on the distance to the known positions of the Bluetooth beacons using the trilateration method