Logitech harmony volume control via Raspberry pi

[walther]

That sounds interesting. What is required to get this Unpn interface running? (Not the CEC to raspberry part) What software do I need to install on the raspberry?

I wrote the hdmi-cec -> upnp in nodejs (JavaScript), the upnp-part is handled by a library called node-ssdp (https://github.com/diversario/node-ssdp) for discovery and raw xml for volume up/down and to get the current volume.