OBD diagnostic system in vehicles with web management interface

Za diagnostiko modernih avtomobilov potrebujemo ustrezno strojno in programsko opremo. V diplomskem delu smo se posvetili Volkswagnovemu protokolu KWP1281, razširjenem v skupini vozil VAG še pred uvedbo standardiziranega protokola CAN. Namen dela je bil spoznati delovanje diagnostike in programsko implementirati protokol KWP1281 na namenskem mikroračunalniku. K temu smo dodali vezje za pretvorbo signalov 12 V iz avtomobila na 5 V, primernih za priključke UART na mikroračunalniku, ter vezje za napajanje mikroračunalnika neposredno iz standardiziranega vmesnika OBD. Mikroračunalnik se med delovanjem povezuje na spletni strežnik VPS, ki teče na oblačni platformi komercialnega ponudnika storitve. Na strežniku teče aplikacija v programskem jeziku Go, ki služi kot zaledni del enostavnemu spletnemu vmesniku. Ta nam omogoča nadzor in upravljanje mikroračunalnika s pomočjo operacij branja in brisanja trenutnih napak na računalniku v vozilu ter branja trenutnih diagnostičnih parametrov v realnem času. Vsi prebrani diagnostični podatki se shranjujejo v podatkovno zbirko BoltDB, kar omogoča kasnejše pregledovanje in analizo. Končna implementacija deluje dobro, s čimer smo izpolnili zadane cilje spoznavanja in implementacije delujočega protokola. Narejen končni prototip predstavlja uporabno orodje za osnovno diagnostiko avtomobilov, ki uporabljajo protokol KWP1281.Modern cars need the right hardware and software for diagnostics. In this thesis, we focus on the Volkswagen KWP1281 protocol, which was widespread in the VAG group of vehicles before the introduction of the standardised CAN protocol. The aim of the thesis was to learn about the operation of the diagnostics and to implement the KWP1281 protocol in software on a dedicated microcomputer. We also added circuitry to convert 12 V signals from the car to 5 V suitable for the UART pins on the microcomputer, and circuitry to power the microcomputer directly from the standardised OBD interface. The microcomputer connects during operation to a VPS web server running on a cloud platform from a commercial service provider. The server runs an application in the Go programming language which serves as a back-end to a simple web interface. The latter allows us to control and manage the microcomputer by means of read and erase operations of the error codes stored in engine control unit and capturing the current diagnostic parameters in real time. Captured diagnostic data is stored in the BoltDB database, allowing later inspection and analysis. Final implementation works well, so our goal of learning about the KWP1281 protocol and creating a working prototype on a dedicated microcomputer was successfully achieved. The final prototype works well as a basic diagnostics tool for vehicles using KWP1281 protocol