ESP32-C6 Standalone OpenThread Border Router

A standalone Thread Border Router for the Seeed Studio XIAO ESP32-C6 that integrates with Home Assistant. Each device is powered by USB-C only — no host computer or data connection required after flashing.

The primary use case is joining an existing Thread network so the ESP32-C6 extends your mesh as an additional border router.

Hardware

• Seeed Studio XIAO ESP32-C6 (or any ESP32-C6 development board)
• USB-C cable for flashing & power
• Any USB power source (phone charger, power bank, etc.)

Features

• Standalone operation — USB power only, no host needed
• Wi-Fi backbone — connects to your home network wirelessly
• Native 802.15.4 — hardware Thread radio, no external module
• Pre-provisioned joining — paste your Thread dataset TLV and flash
• Configurable device names — run multiple OTBRs with unique identities
• Home Assistant discovery — auto-discovered via mDNS
• OpenThread CLI — serial console for provisioning & diagnostics
• NVS persistence — Thread credentials survive reboots
• NAT64 / DNS64 — Thread devices can reach IPv4 services
• SRP Server — Thread device service registration

Quick Start

1. Prerequisites

Install one of the following:

Option	Install
VS Code ESP-IDF Extension (recommended)	VS Code + ESP-IDF extension
ESP-IDF command line	ESP-IDF v5.3+

2. Configure

Edit main/config.h before flashing each device:

// Give each border router a unique name
#define DEVICE_NAME     "otbr-01"

// Your home Wi-Fi
#define WIFI_SSID       "YOUR_WIFI_SSID"
#define WIFI_PASSWORD   "YOUR_WIFI_PASSWORD"

Joining an existing Thread network (recommended)

Get your Thread network's active dataset TLV hex string, then paste it into main/config.h:

#define THREAD_DATASET_TLVS  "0e080000000000010000000300001935060004001fffe0..."

Where to find the TLV hex string:

• Home Assistant: Settings → Devices & Services → Thread → your network → "Active Operational Dataset" (copy the hex)
• Another OTBR's CLI: dataset active -x
• Apple Home: Settings → Thread Network → scroll down → copy credential

The device will automatically join the network on boot. The dataset is saved to NVS, so it persists across reboots.

Waiting for provisioning (alternative)

If you leave THREAD_DATASET_TLVS empty (""), the device starts with no Thread dataset and waits for credentials via Home Assistant discovery or serial CLI.

3. Build & Flash

Using VS Code ESP-IDF Extension

1. Install the ESP-IDF extension — when prompted, let it install ESP-IDF v5.5 (handles Python, toolchains, everything)
2. Open this folder in VS Code
3. Ctrl+Shift+P → "ESP-IDF: Set Espressif Device Target" → select esp32c6
4. Ctrl+Shift+P → "ESP-IDF: Build your project"
5. Plug in the ESP32-C6 via USB-C
6. Ctrl+Shift+P → "ESP-IDF: Flash your project"
7. Ctrl+Shift+P → "ESP-IDF: Monitor your device"

Using idf.py (command line)

# 1. Set the target chip
idf.py set-target esp32c6

# 2. (Optional) Fine-tune config — sdkconfig.defaults is applied automatically
idf.py menuconfig

# 3. Build
idf.py build

# 4. Flash (adjust port if needed)
idf.py -p /dev/ttyACM0 flash      # Linux
idf.py -p COM3 flash               # Windows

# 5. Monitor serial output
idf.py -p /dev/ttyACM0 monitor    # Linux
idf.py -p COM3 monitor             # Windows

4. Monitor

To see logs and use the OpenThread CLI:

idf.py -p COM3 monitor

5. Verify It Joined

Once the device boots, the serial log should show:

Thread dataset loaded from config (XX bytes)
Thread interface up — joining network...
Thread role changed: child
Thread role changed: router

If you see router or leader, the device has successfully joined the Thread network and is providing border routing services.

You can also check from the CLI:

> state
router
> ipaddr
fd12:3456:789a:1::abcd
...

6. Home Assistant Discovery

1. Go to Settings → Devices & Services → Thread
2. Your new OTBR should appear (named as per DEVICE_NAME)
3. If you used THREAD_DATASET_TLVS, it's already on the correct network
4. If you left it empty, HA can push your Thread credentials to the device

Running Multiple OTBRs

To deploy additional border routers:

1. Edit main/config.h — change only DEVICE_NAME:

   #define DEVICE_NAME  "otbr-02"

2. Keep the same THREAD_DATASET_TLVS (all OTBRs share one Thread network)
3. Flash to the next ESP32-C6
4. Repeat for otbr-03, etc.

All devices should use the same Wi-Fi credentials and the same Thread dataset.

Useful OpenThread CLI Commands

Command	Description
state	Current role (disabled/detached/child/router/leader)
dataset active -x	Show current active dataset as hex TLV
dataset set active <hex>	Set active dataset
ifconfig up	Enable the Thread interface
thread start	Start Thread
thread stop	Stop Thread
ipaddr	Show all IPv6 addresses
neighbor table	Show connected Thread neighbors
netdata show	Show Thread network data
br state	Border router state
factoryreset	Erase all settings and restart

RF Coexistence Note

The ESP32-C6 has a single 2.4 GHz radio shared between Wi-Fi and 802.15.4 (Thread) via time-division multiplexing. This means:

• Wi-Fi and Thread cannot receive simultaneously
• Higher Wi-Fi traffic may cause some Thread packet loss
• This is adequate for home use with small-to-medium Thread networks

For production or high-reliability deployments, Espressif recommends a dual-SoC design (e.g., ESP32-S3 + ESP32-H2 with separate radios). For most Home Assistant setups, the single-chip ESP32-C6 works well.

Troubleshooting

Device not appearing in Home Assistant

• Verify the ESP32-C6 is connected to Wi-Fi (check serial logs for IP address)
• Ensure HA and the ESP32-C6 are on the same network/subnet
• Check that mDNS is not blocked by your router
• Restart the Thread integration in HA

Wi-Fi keeps disconnecting

• Move the device closer to your router
• Check for interference on your Wi-Fi channel
• The serial log will show reconnection attempts

Thread stuck in "detached" state

• Verify the dataset matches your existing Thread network exactly
• Make sure THREAD_DATASET_TLVS was copied correctly (no extra spaces)
• Check that the Thread channel isn't congested
• Try factoryreset and re-provision

Build errors

• ESP-IDF v5.3+ is required for full C6 + OTBR support
• Run idf.py fullclean and rebuild if sdkconfig gets out of sync
• Verify sdkconfig.defaults is in the project root

"No Thread dataset configured" on boot

• You left THREAD_DATASET_TLVS empty and THREAD_AUTO_START is 0
• Either paste your dataset TLV hex into main/config.h and reflash, or provision via serial CLI or Home Assistant

Project Structure

esp32c6-otbr/
├── CMakeLists.txt          # Top-level ESP-IDF cmake
├── partitions.csv          # Custom partition table
├── sdkconfig.defaults      # ESP-IDF Kconfig defaults (OpenThread, Wi-Fi, etc.)
├── README.md               # This file
└── main/
    ├── CMakeLists.txt      # Main component cmake
    ├── idf_component.yml   # Managed component dependencies (mdns)
    ├── config.h            # ★ USER CONFIG — edit this per device ★
    └── main.c              # Application entry point

License

MIT — use freely for your home automation projects.