Prerequisites for the installation

If WireGate 1.1 or later is used, CometVisu 0.8.5 is already preinstalled and can be easily used. To install the old CometVisu on a WireGate, there are :doc: further information <wiregate>.

To be able to use the CometVisu the system needs to fulfill a few prerequisites.

These are

  • a backend to connect the KNX bus
  • [optional] rrdtool for diagrams
  • [optional] InfluxDB for diagrams
  • a web server with (optional but recommended) PHP support
  • the CometVisu software package

Backend - knxd/eibd or OpenHAB

As a backend an instance of eibd or its successor knxd can be used as well an OpenHAB installation.

The installation of the backend is described under Install eibd .

Graphentool - RRDtool

An optional but much-recommended component is rrdtool to provide the data for creating graphs. There are many ways to pass data to rrds and the use of rrdtool is documented in depth. The installation of rrdtool for CometVisu is described under RRDtool.

Web server

The relevant files to connect via eibd/knxd are CGI programms, usually located at /usr/lib/cgi-bin/. They must be executable for the account of the web server. This could be enforced by:

chmod +x /usr/lib/cgi-bin/r
chmod +x /usr/lib/cgi-bin/l
chmod +x /usr/lib/cgi-bin/w
chmod +x /usr/lib/cgi-bin/rrdfetch

When these files are symbolic links also the link targets (located e.g. at /usr/local/bin or /usr/share/knxd/examples/bin) must be executable as well.

To be able to use additional components like the editor the web server must support PHP.


For the lighttpd web server an example configuration is given. (Other web servers are also possible, of course). Please make sure that you are changing the example parameters to fit your need.

To install lighttpd on a Debian or Ubuntu system:

apt-get install lighttpd


server.modules = (
#       "mod_rewrite",

server.document-root        = "/var/www"
server.upload-dirs          = ( "/var/cache/lighttpd/uploads" )
server.errorlog             = "/var/log/lighttpd/error.log"             = "/var/run/"
server.username             = "www-data"
server.groupname            = "www-data"

index-file.names            = ( "index.php", "index.html",
                                "index.htm", "default.htm",
                               " index.lighttpd.html" )

url.access-deny             = ( "~", ".inc" )

static-file.exclude-extensions = ( ".php", ".pl", ".fcgi" )

## Use ipv6 if available
#include_shell "/usr/share/lighttpd/"

dir-listing.encoding        = "utf-8"
server.dir-listing          = "enable"

compress.cache-dir          = "/var/cache/lighttpd/compress/"
compress.filetype           = ( "application/x-javascript", "text/css", "text/html", "text/plain" )

include_shell "/usr/share/lighttpd/"
include_shell "/usr/share/lighttpd/"


# /usr/share/doc/lighttpd-doc/cgi.txt

server.modules += ( "mod_cgi" )

$HTTP["url"] =~ "^/cgi-bin/" {
        cgi.assign = ( "" => "" )

## Warning this represents a security risk, as it allow to execute any file
## with a .pl/.py even outside of /usr/lib/cgi-bin.
cgi.assign      = (
        ".pl"  => "/usr/bin/perl",
        ".php" => "/usr/bin/php-cgi",
        ".py"  => "/usr/bin/python",


### Add cgi for cometvisu
alias.url += ( "/cgi-bin/" => "/usr/lib/cgi-bin/" )
compress.filetype += ("application/javascript", "application/xml", "application/octet-stream")

Installing CometVisu

The CometVisu can be downloaded at and unpacked at the web root, most likely in it’s own directory (e.g. /var/www/visu/).

The released versions of the CometVisu are located at

A documentation of an install procedure for the Raspberry Pi is avilable under CometVisu auf Raspberry Pi.

Testing the installed CometVisu

Just open http://MyServer/visu/ in the browser.

Have fun!