FGRFMesh is an open mesh communication platform for reliable local wireless links in the sub-GHz band. The first version is focused on 868 MHz communication and is designed for embedded systems, robotics, telemetry, industrial automation, and IoT projects where Wi-Fi is crowded, unreliable, or not the right tool for the job.

FGRFMesh provides an XBee-style workflow with UART/API packet communication, AT-command-style configuration, RSSI/link diagnostics, and mesh-style routing. It is intended to make sub-GHz mesh networking easier to integrate into real products, while keeping the hardware and firmware more open and developer-friendly than closed commercial radio modules.In order to make development and integration easy, we’ve created an embedded module and a devkit:

The FGRFMesh ESP32 OLED Development Module is a standalone development and debugging module based on the ESP32 with USB, an OLED display, Wi-Fi support, and an integrated 868 MHz radio interface.

The FGRFMesh STM32 XBee-Compatible Module is a compact STM32-based module in an XBee-style form factor that can be used with XBee-compatible carrier boards, including Digi development boards.

Grow Your Mesh Skills

The current implementation uses an ADF7023 sub-GHz radio. The first production version is 868 MHz, but the platform can also be adapted to 433 MHz and 915 MHz with relatively small changes to the RF front end and matching network. In the longer term, we plan to extend the FGRFMesh family to other radio technologies as well, including LoRa and UWB, because the main value of the project is the mesh communication layer rather than one specific radio chip.

We originally developed FGRFMesh for our own robotics and automation projects, especially AGV and AMR robots for warehouse environments. In these systems, Wi-Fi channels can be overloaded by access points, handheld terminals, cameras, barcode scanners, and other equipment. That makes Wi-Fi less predictable for telemetry, control, coordination, and diagnostics.

FGRFMesh gives developers another option: a local sub-GHz mesh network that can carry UART/API packets between devices without requiring every node to be directly connected to a central gateway. This is useful for robots, mobile equipment, distributed sensors, remote controllers, industrial devices, and test systems that need a practical wireless link with routing and link diagnostics.

One common use case is replacing or supplementing XBee-style sub-GHz radio modules in existing products. Digi XBee SX 868 and DigiMesh are strong existing solutions, but we have often faced availability problems when modules were out of stock or had long lead times. FGRFMesh is intended to provide a more open and hackable alternative that follows similar communication principles and can be integrated into systems that already use XBee-style UART/API workflows. Suited for a wide array of applications like robot telemetry, remote sensor networks, and warehouse automation, FGRFMesh can improve the trickiest wireless scenarios.

Features & Specifications

FGRFMesh ESP32 OLED Development Module

• ESP32-based standalone development/debug module
• Integrated 868 MHz sub-GHz radio interface
• OLED display for local status and debugging
• USB connection for programming, power, and serial communication
• Wi-Fi support through ESP32
• Designed for development, diagnostics, field testing, and quick prototyping
• Can run prebuilt FGRFMesh firmware or custom Arduino-based firmware
• Dimensions: 40 mm x 105 mm / 1.57 in x 4.13 in
• Weight: 19.75 g / 0.70 oz

FGRFMesh STM32 XBee-Compatible Module

• STM32-based embedded radio module
• XBee-style form factor
• Designed for XBee-compatible carrier boards and development boards
• Tested with Digi development hardware
• Integrated 868 MHz sub-GHz radio interface
• UART/API communication
• Intended for integration into embedded devices and products
• Can run prebuilt FGRFMesh firmware or custom Arduino/STM32 firmware
• Dimensions: 22 x 34 mm (0.87 x 1.34 in)
• Weight: 2.81 g (0.10 oz)

Radio & Communication

• Current frequency band: 868 MHz
• Planned future hardware variants: 433 MHz and 915 MHz
• Radio IC: Analog Devices ADF7023
• Mesh-style packet routing (Modified Ad hoc On-Demand Distance Vector Protocol)
• UART/API packet communication
• XBee-style API frame support
• AT-command-style configuration
• Remote/local RSSI reporting
• XCTU-compatible workflow for common testing and configuration tasks
• Tested with XCTU mesh topology, throughput test, and range test tools
• Current tested throughput: approximately 20 kbps in the tested configuration
• Supports direct communication and routed communication through mesh nodes

Throughput and Range Tests

Firmware Features

• ESP32 and STM32 firmware targets
• ADF7023 radio initialization and control
• Packet TX/RX handling
• Mesh route discovery and packet forwarding
• UART/API frame parser
• AT command response handling
• Remote AT command support for selected functions
• RSSI reading and link diagnostics
• Frequency/channel configuration logic
• Arduino IDE support through the ADF7023 library

Current Supported XBee-Style Functions

The current firmware implements a practical subset of XBee-style behavior rather than full Digi/XBee feature parity. For a comprehensive list of supported commands and features, please check our documentation at fgrfmesh.factorial-group.com.ua.

FGRFMesh is not affiliated with or endorsed by Digi. XBee-style compatibility is implemented as a practical integration and development workflow, not as a complete clone of every Digi module feature.

Open Source

FGRFMesh is intended to be an open and developer-friendly project. The current Arduino library for the ADF7023 radio and AODV are available on our Github.

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