I recently moved into an apartment with an existing KNX setup, but without access to the original ETS project or software. After some research, I found a solution that allowed me to connect my KNX system to Home Assistant without the need for an ETS interface. Here’s how I did it and what I learned along the way.
The Challenge
The existing KNX installation was set up years ago and controlled via a phone line—something no one uses anymore. My goal was to integrate this system into my Home Assistant setup, but I didn’t have the ETS project or the necessary software to configure it. This left me with a working KNX setup but no way to control it through my smart home ecosystem.
The Solution
After some digging, I discovered the TUL board from Busware. This ESP32-based device acts as a bridge between the KNX bus and Home Assistant via Wi-Fi. It was perfect for my situation because it didn’t require the ETS software and could be powered directly from the KNX cabinet.
What I Needed
- TUL Board: The core of the setup, connecting to the KNX bus and providing Wi-Fi connectivity.
- KNX Bus Cable: I needed a short cable to connect the TUL board to the KNX bus. I opted for 20 cm, but only found it in 5m lengths, so I had to cut it down.
- Power Supply: A 12V DC to USB-C transformer to power the TUL board from my KNX cabinet.
Setup Steps
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Connect the TUL Board: I connected the TUL board to the KNX bus using the black and red wires. Initially, I tried using standard stranded wires, but they didn’t work well with the KNX bus connectors. The TUL board was then powered using a power bank while I set it up, but I later moved it to a dedicated 12V DC power supply in the KNX cabinet.
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Flash the TUL Board: I followed the instructions from Busware to flash the TUL board. This involved downloading the firmware and using a simple setup process to connect it to my Wi-Fi network.
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Configure Home Assistant: After connecting the TUL board to my network, I set up the KNX integration in Home Assistant. I used the official KNX integration and configured it to listen to the KNX traffic. The process involved checking the KNX group monitor to identify the addresses of the devices I wanted to control.
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Mapping Devices: I started by mapping the AC controllers and other climate control devices. For example, I set up a sensor for the temperature in my living room and a number entity to adjust the temperature threshold. Here’s a snippet of the configuration I used:
yaml
knx:
sensor:
- name: “Temp Living”
state_address: “1/1/6”
type: temperature
sync_state: 3
number:
- name: “Temperature threshold Living”
address: “1/1/7”
state_address: “1/1/7”
type: temperature
min: 18
max: 23
step: 0.5
mode: slider
- Testing and Automation: Once everything was set up, I tested the integration by adjusting the temperature thresholds and monitoring the changes in Home Assistant. I also set up some basic automations, such as changing the temperature based on the time of day or when I leave the house.
Lessons Learned
- KNX Bus Connectivity: The TUL board worked flawlessly once connected correctly. It’s important to use the right type of wires for the KNX bus to ensure a stable connection.
- Power Management: The TUL board requires a stable power supply. Using a dedicated transformer in the KNX cabinet ensured that the board stayed powered even during network outages.
- Home Assistant Configuration: The official KNX integration in Home Assistant is robust, but it requires some trial and error to map the correct addresses. The group monitor tool was invaluable in identifying the right KNX addresses.
Conclusion
Connecting an existing KNX setup to Home Assistant without access to the original ETS project is definitely possible with the right tools and some patience. The TUL board from Busware was the key to this integration, and it opened up a whole new level of smart home control for me. If you’re facing a similar situation, I highly recommend exploring this solution. It’s a bit of a DIY project, but the result is well worth the effort!
If you have any questions or need help setting this up, feel free to reach out. I’d be happy to share more details or troubleshoot any issues you might encounter.