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KNX IP Router DIY

Overview

IP Router is a KNX equipment connecting KNX network and IP network, to help IP devices receive and send signals on the KNX bus.

However, some kinds of IP Routers can only connect to IP network via RJ45 connector, without the capability of WIFI, which will cause inconvenience in some environment. Moreover, IP Router is always expensive.

This project aims building a convenient, stable, and cheap IP Router, by using open source software and simple hardware.

Architecture

We choose Raspberry Pi as the main hardware, and run the open source knxd on it.

Raspberry Pi can connect to IP network easily, but on which, there is no interface connected to KNX bus directly. Therefore, we need to make a hardware(KNX Bridge Board), which could connect to KNX bus on one hand, and connect to Raspberry Pi on the other, so that knxd on Raspberry Pi can send and receive data in KNX network.

KNX Bridge Board

The KNX Bridge Board is based on ncn5120 chip, which can communicate with KNX bus.

On the other hand, the KNX Bridge Board shall communicate with knxd running on Raspberry Pi. Three connection modes are supported, you could choose one of them.

1. Connecting via USB

   KNX Bridge Board has a mini USB interface, which could be connected to USB on raspberry pi.

   HAChina KNX Bridge Board type A and type B supports this connection mode both.

2. Plugging into Raspberry PI's mainboard

   As a shield, KNX Bridge Board could be plugged into the 40-pin connector on raspberry pi(ZeroW/3B/3B+/4B) mainboard directly.

   HAChina KNX Bridge Board type B supports this connection mode.

   You will have to enable the primary UART, if you connect this way.

   How can I enable the primary UART on PI OS?

   How can I enable the primary UART on HassOS?

3. Communicating via WIFI

   As a sheild of NodeMCU-32s, KNX Bridge Board can plug into the 38-pin connector on NodeMCU-32s. Setup NodeMCU-32s, then it can communicate with knxd via Wifi.

   HAChina KNX Bridge Board type A supports this connection mode.

Where can I buy a KNX Bridge Board?

What's the difference between KNX Bridge Board type A and type B?

Can I make a KNX Bridge Board myself?

Run knxd

Raspberry PI ZeroW/3B/3B+/4B have been tested and recommended.

Must knxd runs on raspberry pi?

Run in docker

• Install docker

  • OS： Pi OS

  • install docker

    curl -fsSL get.docker.com | sudo sh

  • add user pi(or any user you login as) into group docker

    sudo usermod -aG docker pi

• Create configuration file /etc/knxd.ini

  knxd.ini is the configuration file of knxd. You can find knxd.ini's manual from its github website.

  # an example of knxd.ini
  [main]
  addr = 0.0.1
  client-addrs = 0.0.2:10
  connections = server,A.tcp,interface
  logfile = /dev/stdout
  
  [A.tcp]
  server = knxd_tcp
  
  [server]
  server = ets_router
  tunnel = tunnel
  router = router
  discover = true
  name = knxd
  
  [interface]
  driver = ncn5120
  
  # USB link to KNX Bridge Board
  device = /dev/ttyUSB0
  baudrate = 19200
  
  # 40-pin link to KNX Bridge Board
  #device = /dev/serial0
  #baudrate = 19200
  
  # TCP link to KNX Bridge Board
  #ip-address = 192.168.1.3
  #dest-port = 5120

  Remove corresponding comment symbols in [interface] section, according to different connection methods of KNX Bridge Board.

• Run docker image zhujisheng/armv7-addon-knxd

  docker run --rm \
  --name knxd --network="host" \
  --tmpfs /etc/cont-init.d \
  --device=/dev/ttyUSB0 \
  -v /etc/knxd.ini:/etc/knxd.ini:ro \
  zhujisheng/armv7-addon-knxd 
  

  Set parameter --device=/dev/serial0 when KNX Bridge Board is plugging into Raspberry PI's mainboard; Remove parameter --device when KNX Bridge Board is communicating via WIFI.

If my computer is not armv7, where can I get the docker image?

Must knxd runs as a docker container or HomeAssistant add-on?

Run as HomeAssistant add-on

• Install

  Add the add-on repository https://github.com/da-anda/hass-io-addons or https://github.com/zhujisheng/hass-io-addons

  Install add-on:KNXD daemon in the repository.

  What's the difference between knxd add-ons in da-anda and zhujisheng's add-on repository?

• Configuration

  address: 0.0.1
  client_address: '0.0.2:8'
  interface: ncn5120
  device: /dev/ttyAMA0
  log_error_level: warning
  usb_filters: single
  custom_config: |-
    [main]
    addr = 0.0.1
    client-addrs = 0.0.2:10
    connections = server,A.tcp,interface
    logfile = /dev/stdout
  
    [A.tcp]
    server = knxd_tcp
  
    [server]
    server = ets_router
    tunnel = tunnel
    router = router
    discover = true
    name = knxd
  
    [interface]
    driver = ncn5120
  
    # USB link to KNX Bridge Board
    device = /dev/ttyUSB0
    baudrate = 19200
  
    # 40-pin link to KNX Bridge Board
    #device = /dev/serial0
    #baudrate = 19200
  
    # TCP link to KNX Bridge Board
    #ip-address = 192.168.1.3
    #dest-port = 5120

  The valid part of the configuration is under custom_config. However, the rest configurations have to be retained, although they have not any effect at all, because they are set as mandatory items in this add-on.

  Remove corresponding comment symbols in [interface] section, according to different connection methods of KNX Bridge Board.

How can I config KNX devices in HomeAssistant?

How can I control KNX devices in Node-RED?