Design and control of a dual-axis sunlight tracker using myRIO microcontroller

Pri predmetu osnove mehatronike v 3. letniku 1. stopnje UN smo se seznanili z uporabo mikrokrmilnika National Instruments myRIO in z njegovim programiranjem v programskem okolju LabView. Pri tem smo uporabili številne senzorje, periferijo in krmiljenje s pomočjo pulzno širinske modulacije, a nikdar komunikacijskih protokolov. Različni komunikacijski protokoli (SPI, I2C), ki jih omogoča dotični mikrokrmilnik, in posledično krmiljenje periferije (koračni servomotorji) pa je glavna tematika te diplomske naloge. Predvsem je poudarek na nadgrajevanju že osvojenega znanja s pomočjo aplikacije, ki jo zasledimo tudi v vsakdanjem življenju. To je sledilnik najmočnejšemu viru svetlobe oz. sledilnik sončne svetlobe (ang. solar tracker). Sledilnik sem realiziral s pomočjo štirih svetlobnih senzorjev in dveh servomotorjev, ki omogočata premikanje platforme v dveh smereh (gor-dol in levo-desno). Pri tem sem uporabil pulzno širinsko modulacijo za nadzor in premikanje koračnih servomotorjev in SPI protokol za komunikacijo s senzorji. Sprva je bilo načrtovano, da bi bila platforma narejena iz plastike, s pomočjo 3-D tiskalnika, a je bila na koncu sestavljena iz lepenke in trde pene. Izziv je bil tudi zagotoviti zadovoljivo natančnost pri sledenju svetlobnemu viru, kar pa je bilo rešeno s pomočjo pokončnega kvadra, ki ustvarja senco, kadar platforma ni pravokotno na svetlobo. To za senzor pomeni, da se mora platforma premakniti. Praktični preizkus na sončni svetlobi (in tudi pri ročni svetilki) je bil uspešen in dosežena je bila načrtovana natančnost sledenja. Dotični sledilnik se lahko v nadaljevanju uporabi v povsem praktični in trenutno zelo aktualni aplikaciji, in sicer kot sledilnik sončne svetlobe za fotovoltaične panele, ki proizvajajo električno energijo. Čim bolj so ti paneli poravnani s soncem, tem več električne energije proizvedejo in posledično se jim močno poviša izkoristek.In the course Basics of Mechatronics we learned how to use and program the National Instruments myRIO microcontroller in the LabView software environment. We used many sensors, peripherals and motor control with the help of pulse width modulation, but we never touched or mentioned communication protocols. The main topic of this thesis are various communication protocols (SPI, I2C) enabled by the microcontroller in question and the resulting peripheral control (stepping servomotors). The emphasis is on upgrading existing knowledge with the help of an application that we can see in everyday life. That is a light source tracker or more commonly known as solar tracker. I decided to make the tracker with the help of four light sensors and two stepper servomotors, which enable the platform to move in two directions (up-down and left-right, also known as pan and tilt). I used pulse width modulation to control and move the stepper servomotors and the SPI protocol to communicate with the sensors. Initially I planned to make the platform out of plastic with the help of 3-D printer, but I ended up making it out of cardboard and rigid foam. The challenge was to ensure relatively accurate tracking of the light source, which I solved by using an upright cube mounted in the center of the four light sensors, which creates a shadow when the platform is not perpendicular to the light (sun). A shadow over the sensor means that the platform needs to move. A practical field test in sunlight (and indoors with a flashlight) was successful and the intended tracking accuracy was achieved. The tracker in question can then be used in a completely practical and currently very relevant application, namely as a sun tracker for photovoltaic panels that produce electrical energy. The more these panels are aligned with the sun, the more electrical energy they produce and, as a result, their efficiency is greatly increased