Razvoj in ovrednotenje elektronskih senzorjev za zaznavanje dežja

PRHAJ, ŽIGA (author), Jankovec, Marko (mentor)

Zaključno delo obsega ovrednotenje različnih principov avtomatske detekcije dežja na podlagi izdelanih prototipnih elektronskih senzorjev. Osredotočili smo se na naslednje principe detekcije: optični, kapacitivni in zvočni princip. Na začetku smo načrtali mehansko zasnovo. Pri optičnem principu smo izbrali prosojen material. Oblikovali smo ga v obliki prizme, da se je svetloba med dvema različnima optičnima medijema odbila pod ustreznim kotom. Svetlečo diodo smo uporabili za oddajno stran in foto diodo za sprejemno stran. Za kapacitivni princip smo načrtovali posebno grabljasto strukturo prevodnih linij na izolativnem substratu. Prevodne linije smo prevlekli z izolativno zaščitno snovjo. Pri zvočnem principu smo uporabili tanko pločevinasto ploščo, ki ob padcu vodne kapljice zavibrira. Na spodnjo stran plošče smo pritrdili piezoelektrični element. Za vsak princip smo načrtovali električna vezja in jih sestavili na preizkusni ploščici. Vezja smo povezali z mehanskim delom. Izračune komponent smo potrdili z meritvami delov vezij in prišli do končnih vrednosti električnih komponent v vezju. Nato smo izdelali tiskana vezja. Vse prototipe smo zasnovali na razvojnem tiskanem vezju, ki ima procesor ATmega. Za krmiljenje prototipov in izpis meritev je bilo treba napisati ustrezne programe. Simulirali smo padanje vodnih kapljic, lažne pojave in izmerili odziv prototipov. Meritve smo izvedli tudi na zunanjih pogojih ob dežju. Rezultate smo obdelali in ovrednotili detekcijo dežja v časovnem in frekvenčnem prostoru. Zahtevnost izdelave je odvisna od posameznega detektorja in pripadajočega električnega vezja. Iz meritev je razvidno, kateri senzor se izkaže za boljšega in primernejšega za določeno aplikacijo. Opaziti je tudi slabosti za dotični detektor in njegovo obnašanje pri lažni detekciji.

• Language: Slovenian
• Keywords: senzorji, detektor dežja, optika, kapacitivnost, zvok
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2019
• PID: 20.500.12556/RUL-111224
• Publication date in RUL: 26.09.2019

Secondary language

• Language: English
• Title: Development and evaluation of electronic rain detection sensors

Abstract

This thesis presents the evaluation of various principles of automatic rain detection, based on prototype-designed electronic sensors. We focused on the following detection principles: optical, capacitive and sound principle. Initially, we planned a mechanical design. For the optical principle, we chose the transparent material. It was designed in the form of a prism, so that the light was reflected between two different optical media at an appropriate angle. The LED was used for the transmit side and the photo diode for the receiving side. For the capacitive principle, we planned a special structure of interleaved tracks on the insulating substrate. The tracks were coated with an insulating protective agent. For the sound principle we used a thin metal sheet, which vibrates when a water droplet falls on it. A piezoelectric element was attached to the underside of the panel as a sensing element. We designed electrical circuits for each principle and assembled them on a test board. We connected the circuits to the mechanical part. The component calculations were confirmed by measurements of the circuits and the final values of the electrical components in the circuit were determined. Then we made printed circuit boards (PCBs). All prototype PCBs were controlled by a microcontroller development board with an ATmega microcontroller. Appropriate programs had to be written to control the electronics and display measurement results. We simulated the dropping of water droplets, false detection and measured the response of prototypes. We also carried out measurements in realistic environment under different outdoor conditions including the rain. The results were processed and the rain detection in time and frequency space was evaluated. The complexity of the manufacture depends on the individual detector and the associated electrical circuit. The measurements show which sensor turns out to be better and more appropriate for a particular application. We also identified some disadvantages of each detector and its behavior in case of false detection.

• Keywords: sensors, rain detector, optics, capacitance, sound