OqtaDrive emulates a bank of up to 8 Microdrives for use with a Sinclair Spectrum (with Interface 1) or QL machine. The goal is to functionally create a faithful reproduction of the original. That is, on the Spectrum/QL side, operating the emulated Microdrives should feel exactly the same as using the real thing.
OqtaDrive is built around an Arduino Nano that connects via its GPIO ports to the Microdrive interface and via serial connection to a daemon running on a host machine. This daemon host could be anything, ranging from your PC to a small embedded board such as a RaspberryPi Zero, as long as it can run a supported OS (Linux, MacOS, Windows). The same Nano can be used with both Spectrum and QL, without any reconfiguration.
While the Nano is essentially a low-level protocol converter, the daemon takes care of storing and managing the cartridges. It additionally exposes an HTTP API endpoint. A few shell commands are provided that use this API and let you control the daemon, e.g. load and save cartridges into/from the virtual drives. A web UI is available as well.