Debugging is a must when coding, regardless of how big or complex a project is. And althought there are tons of debugging tools out there, most are overpowered for my needs or simply introduce unnecessary code even when in the release version.
Logging is not only a powerful debugging and maintenance tool, but also a basic security element. In this case I wanted to save telemetry data of a multirotor without sending it to my laptop. Thus I wrote a simple logger that stores everything on the on-board uSD card. Although it's not perfect, it has proven to work as expected and be quite lightweight.