Brezžična komunikacija na frekvenčnem pasu 2,4 GHz s tehniko LoRa za rabo v modelarstvu

PEVEC, MATEJ (author), Fajfar, Iztok (mentor)

V tem diplomskem delu se lotimo izdelave modula za brezžično komunikacijo z modelarskimi modeli na osnovi projekta ExpressLRS (ELRS) za vgradnjo v sistem RadioMaster TX16S. Ker z izdelavo modula nadomestimo obstoječ multiprotokol modul, se najprej vprašamo o smiselnosti izdelave takega sistema in analiziramo obstoječe rešitve. Projekt ELRS prisega na modulacijo LORA, medtem ko bolj tradicionalni sistemi uporabljajo preprostejše načine modulacije signala, večinoma po shemi FSK. Zanesljivost sistema ter delovanje večih sprejemnikov hkrati večinoma omogočijo z oddajanjem po metodi FHSS in DSSS. Sledi analiza sistema, v katerega bo modul vgrajen, obstoječega multiprotokol modula v TX16S, referenčnih načrtov za ELRS module in programatorja za ESP32. Na podlagi analize se odločimo za mikrokrmilnik ESP32, USB serijski most CP2102 in radijski modul Ebyte E28-2G4M27S. Za pretvorbo napetosti uporabimo stikalni pretvornik napetosti s krmilnim vezjem LM2831XMF. Na osnovi analize in podatkovnih list izbranih komponent nato sestavimo shemo za modul, naročimo komponente in ga izdelamo. Za sestavljen modul prilagodimo programsko opremo sistema ELRS ter ustrezno nastavimo daljinec TX16S z operacijskim sistemom EdgeTX. Sledi preizkus sistema, kjer ugotovimo, da sistem nudi opazno stabilnejšo povezavo, predvsem zunaj vidnega polja. V primerjavi z bolj tradicionalnim FlySky sistemom ima sicer večjo porabo, ki pa je v kontekstu modelarstva zanemarljiva. Zaključimo, da je ExpressLRS primernejši za rabo kot vgrajeni modul.

• Language: Slovenian
• Keywords: brezžična komunikacija, ExpressLRS, LoRa, modelarstvo
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2022
• PID: 20.500.12556/RUL-137660
• COBISS.SI-ID: 112794115
• Publication date in RUL: 24.06.2022

Secondary language

• Language: English
• Title: Wireless communication in the 2.4 GHz frequency band with LoRa technique for use in model building

Abstract

In this diploma, we tackle the development of a wireless communication module for RC models based on the ExpressLRS (ELRS) project designed for installation in the RadioMaster TX16S system. Because this module replaces the existing multiprotocol module, we first have to ask ourselves whether such a system makes sense and analyze existing solutions. While the ELRS project swears to LORA modulation, older, more traditional links use simpler modulations, mostly the FSK scheme. To make the connection more robust and allow for the connection of multiple systems at once, they mostly use the FHSS or DSSS transmission methods. Afterwards, we analyze the system in which we'll embed the module, the existing multiprotocol module in the TX16S, reference designs for ELRS modules, and an ESP32 programmer. Based on the analysis, we use an ESP32 microcontroller, a CP2102 USB-serial bridge, and an Ebyte E28-2G4M27S RF modem in the design. We choose a switching step-down power supply controlled by an LM2831XMF to convert voltage. Based on this analysis and datasheets of selected integrated circuits, we then plan a scheme for the module, order components and manufacture it. We then adjust the ELRS source code and configure TX16S with EdgeTX accordingly. Afterwards, we test the module and find out that the system offers a significantly more stable connection, especially when breaking the line of sight. In comparison to a more traditional FlySky system, it has a higher consumption, which is, however, negligible in the context of model building. We conclude that ELRS is more suitable for use as an embedded module.

• Keywords: wireless communication, ExpressLRS, LoRa, model building