Open Modbus is an open-source initiative focused on creating reliable, fully transparent hardware and firmware for Modbus-based automation systems.
Our projects include digital/analog I/O modules, STM32-based controllers, and tools for building distributed RS-485 networks.

• Open hardware (schematics, PCB, BOM)
• Open firmware (Modbus RTU, STM32)
• Documentation and wiring guides
• Ready-to-use industrial I/O modules (e.g., OM-64DO)

Explore our repositories — each includes build files, Modbus maps, and examples.
Recommended starting point: OM-64DO, a 64-channel low-side output module.

We welcome improvements, bug reports, and new device ideas.
See each project's CONTRIBUTING.md for guidelines.

Use GitHub Issues for questions or problems.

Thanks for being part of the Open Modbus community!