Reading KNX using Raspberry Pi 3 GPIO

Question

My dad wants me to make kind of a smart home.

I would like to interface with KNX (a home automation protocol) using the GPIO on a Raspberry Pi 3. Ideally, I would like to build a web interface for it, but I don't have a clue how to interface with KNX in the first place.

Any suggestions?

Answer 1

It wont make sense for you to interpret and understand the KNX bus communication protocol directly. There is a massive specification behind the KNX bus which deals with so many problems from device addresses to collision detection. It would take years to master it and unless you develop KNX devices you really should not spend your time on it. You will be better off by doing the following:

• Buy a KNX/IP gateway/interface such as https://www.mdt.de/en/products/product-detail/system-devices/system-devices/ip-interface.html
• Understand that KNX bus traffic can be routed/tunneled to your home LAN/WIFI
• Play around with one of the KNX libraries on GitHub. For example for C#: https://github.com/search?l=C%23&q=knx&type=Repositories&utf8=%E2%9C%93
• If you want, have a look at my experimental .NET Core project which starts a radio streaming process when someone touches a button (in the bathroom in my case). It runs on any operation system (so Raspberry and Linux are fine) and you can find it here: https://github.com/ThomasZeman/KnxNetCore

Answer 2

I see two options for you:

A) use an IP interface (e.g. the ones from MDT) and access the IP interface from your raspberryPi (e.g. with http://calimero-project.github.io/)

B) use a TPUART controller, which makes KNX TP telegrams accessible (r/w) to UART - see http://www.konnekting.de/konnekting-lernen/l1-knx-mit-arduino/

Answer 3

You can't connect the KNX bus to anything on the pi. The KNX bus has its own electrical specs, and you need specialized hardware to connect to it. Such hardware is available, but probably a KNXnet/IP device (such as the Siemens N148) is a better option.

Answer 4

KNX Hat for pi3 and a bunch of other single boardies