// the take
A classroom lab (part of Intel's old Grove/UP2 IoT course) that walks through writing a minimal OPC-UA server and client in C using the open62541 stack — the server exposes fake 'robot' objects, the client browses them. It's for someone learning OPC-UA node modeling concepts for the first time, not for anyone building a real OPC-UA integration.
Builds the example incrementally with full code shown at each step instead of just dumping a finished file, which actually helps for understanding how object types, variable nodes, and mandatory modeling-rule references fit together. It leans on the real open62541 stack rather than reinventing anything, and the client-side browsing code is a reasonable illustration of how OPC-UA address-space traversal works.
The code targets open62541's old 'standard' config API (UA_ServerConfig_standard, UA_ClientConfig_standard, UA_ServerNetworkLayerTCP) that was removed from the library years ago in favor of the plugin-based config — none of this compiles against a current open62541 checkout without a rewrite. Last pushed in 2018 with no CI and no sign it was ever revisited. It's tied to a specific Arduino Create / UP2-board course context, with dead links to that environment, and the client/browse code has zero error checking on service-level status codes, so it's not something to copy into real code as-is.
We read the README, the directory tree and a key source file in October 2026. Nobody pays to be listed. How we judge →