Višenamjenski bežični senzorski čvor

master's thesis

• Title (english): Wireless Multifunctional Sensor Node
• Author: Filip Šklebar
• Mentor: Ratko Magjarević (mentor)
• Committee member: Ratko Magjarević (predsjednik povjerenstva)
• Committee member: Igor Lacković (član povjerenstva)
• Committee member: Željka Lučev Vasić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2019-09-23, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

U ovom radu opisan je razvoj i izrada senzorskog čvora malih dimenzija koji se sastoji od šesterokanalnog elektrokardiografa, troosnog akcelerometara, žiroskopa i magnetometra, senzora za određivanje nadmorske visine te ostalih elektroničkih dijelova neophodnih za obradu i pohranjivanje podataka te komunikaciju putem USB i Bluetooth sučelja. Uređaj posjeduje točno određivanje stanja baterije koju je moguće puniti žičnim ili bežičnim putem. Provedena su mjerenja elektrokardiograma na ispitanicima koji su za to vrijeme izvodili određenu tjelesnu aktivnost. Mjerenja su provođena za vrijeme mirnog sjedenja, hodanja po ravnom, brzog i sporog uspinjanja stubama te vožnje sobnog bicikla.

Analiziran je utjecaj kvalitete snimljenog elektrokardiograma s obzirom na intenzitet pomicanja trupa ispitanika te je zaključeno da sklopovi i algoritmi za obradu signala uspješno otklanjaju artefakte uslijed navedenih oblika fizičke aktivnosti te da elektrode održavaju dobar kontakt s kožom. Primijećeni su manji padovi u kvaliteti signala kod aktivnosti koje traže jače pomicanje trupa.

Analizirani su podaci prikupljeni akcelerometrom te je utvrđeno da je u realnom vremenu moguće razlikovati mirovanje (sjedenje i ležanje) od gibanja. Pri tome nije moguće precizno razlikovati hodanje i uspinjanje uz stube zbog razlike u načinu kretanja među različitim ispitanicima. Za precizno razlikovanje gibanja potrebno je prikupljene podatke obraditi pomoću neuronske mreže te pronaći personalizirane pokazatelje razine i tipa aktivnosti za pojedine osobe i/ili pacijente.

Abstract (english)

In this paper, development and design of a miniature sensor node comprising of a six-channel electrocardiograph and a tri-axial accelerometer, gyroscope and magnetometer, altimeter, as well as other electronic components necessary for processing and storage of acquired data and for communication via USB and Bluetooth interface is described. Device has a battery fuel gauge which enables precise state of the charge tracking. Measurements of electrocardiogram on subjects while they were doing certain physical activity were performed. Measurements were taken while subjects were sitting, walking on a flat surface, climbing stairs slowly and fast and riding a stationary bike.

The influence on the quality of the recorded electrocardiogram due to the intensity of subject movement was analyzed. Circuits and algorithms for data processing successfully suppress artefacts caused by specified types of physical activity. The electrodes maintain good contact with the skin with noticeable dips in signal quality when activities that require greater torso movement are performed.

Accelerometer measurements were analyzed and it was found that in real-time it is possible to distinguish between sitting/lying and movement. However, it is not possible to accurately distinguish between walking and climbing stairs because of differences in individual performance of certain types of activity. To accurately differentiate between various kinds of movements it is necessary to process the collected data using neural networks in order to find personalized features of activity intensity and type for individuals and/or patients.

• Keywords: EKG; Pametni senzorski čvor; Intenzitet tjelesne aktivnosti
• Keywords (english): ECG; Smart Sensor Node; Physical activity intensity
• Language: croatian
• URN:NBN: urn:nbn:hr:168:639279
• Study programme: Title: Electrical Engineering and Information Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije (magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2020-01-07 22:24:59