Afektivna VR čelada

Vukadin, Simon (author), Geršak, Gregor (mentor)

Prevodnost kože je ena od ključnih fizioloških parametrov, ki nam omogoča ugotavljanje čustvenega odziva. Zaradi hitrih sprememb čustvenega stanja ljudi je pomembno, da meritve izvajamo na čim bolj neopazen način. Večina trenutnih metod merjenja ni praktičnih. Rešitev težave je afektivna VR čelada. V notranjost čelade smo vgradili dve elektrodi, ki merita prevodnost kože preko čela. Arduino Nano RP2040 opravi meritve in jih preko omrežja Wi-Fi pošlje na platformo Arduino IoT Cloud, kjer nato meritve tudi grafično prikažemo. Prednost izdelka je v tem, da je izvajanje meritev za uporabnika zelo neopazno, saj so elektrode majhne in udobne za nošenje. Uporabnik se praktično ne zaveda izvajanja meritev, zato imamo pri tem minimalen vpliv na njegovo psihološko stanje. Za izvajanje meritev v navideznem okolju se je kot najbolj primerna izkazala lokacija na čelu. Da bi preverili primernost lokacije, smo meritve hkrati izvajali na čelu in na standardnem mestu na prstih leve roke, pri čemer smo uporabili instrument Biopac MP150 z elektrodami EDA100C. Ugotovili smo, da je odziv na čelu nekoliko manjši, vendar še vedno viden. V uvodu diplomskega dela smo podali teoretično osnovo o prevodnosti kože (zakaj pride do elektrodermalnega odziva), področja uporabe in o metodah merjenja. Prav tako smo predstavili navidezno resničnost (NR oz. VR) ter njeno vlogo pri merjenju psihofizioloških odzivov pri človeku in očala Meta Quest 2, ki smo jih uporabili pri testiranju izdelka. V drugem delu je opisan postopek izdelave afektivne VR čelade. Najprej smo izdelali merilnik, ki temelji na platformi Arduino Nano (vezje, s pomočjo katerega Arduino meri prevodnost, je neinvertirajoči ojačevalnik), nato smo skrbno izbrali elektrode, ki zagotavljajo natančne in zanesljive meritve prevodnosti kože. V tretjem delu smo afektivno VR čelado ovrednotili. Ugotovili smo, da so odzivi, ki jih izmerimo, primerno hitri, vendar z dosti manjšimi amplitudami kot na referenčnem senzorju. Glavni razlog za to je v skoraj šestkrat manjši koncentraciji ekrinih znojnih žlez na čelu v primerjavi s prsti rok.

• Language: Slovenian
• Keywords: prevodnost kože, EDR, navidezna resničnost, Arduino Nano, neinvertirajoči ojačevalnik, operacijski ojačevalnik
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2023
• PID: 20.500.12556/RUL-148811
• COBISS.SI-ID: 163216387
• Publication date in RUL: 31.08.2023

Secondary language

• Language: English
• Title: Affective head mounted display

Abstract

Skin conductance is one of the key physiological parameters that helps us in assessing emotional responses. Because it changes extremely quickly and is very sensitive it is crucial that the measurements are taken as discreetly as possible. Most current methods fail in this regard or just aren’t practical enough. Our solution is the affective head mounted display. Inside of it we have mounted two electrodes that make contact with the forehead, across which skin conductance is then measured. Measurements are taken by Arduino Nano RP2040 and are sent over WiFi to Arduino IOT Cloud platform. Where they are then graphically displayed. Our product is capable of taking measurements very discreetly and that gives it a big advantage over the conventional methods. Because of this the user is hardly aware that they are being measured which gives us more accurate results. Location on the forehead is not as good as on the fingers or foot because it has a lesser concentration of eccrine sweat glands, however through testing we have determined that it is adequate. That was determined by comparing the values and responses on the forehead and the fingers. For reference measurements we used Biopac 150MP with EDA100c electrodes. The response on the forehead was smaller but still clearly visible. In the introduction of this thesis we provided a theoretical basis on skin, virtual reality, skin conductance and its uses in measuring psychological and physiological responses. We dive more thoroughly into electrodermal response and explain why it happens. In the second part of the thesis we describe the process of building the Affective head mounted display. First we built the measuring instrument based on the platform Arduino Nano. Arduino takes measurements with the help of a noninverting amplifier. Then we carefully chose the electrodes that gave us the best result. Lastly we checked how effective our product is in measuring electrodermal response. We did this by comparing it to Biopac 150MP with EDA100c electrodes. We determined that our measured responses are smaller, however they are almost as fast as our reference. The main reason for these differences lies in different concentrations of eccrine sweat glands in our locations.

• Keywords: electrodermal response, HMD, skin, conductance, noninverting amplifier, virtual reality, Arduino Nano