iogear2mqtt

iogear / aten HDMI switch <-> MQTT interface with homeassistant auto-discovery; via the RS-232 port on the switch.

The switch will show up as a device with independent switches for each input; turning on any switch will turn off the previously-selected input. Turning off any switch will do nothing - much like how you can't actually disable an HDMI input on the physical switch with a button press. (Some models of Aten/IOGEAR switches do allow you to turn off the entire input, but that is also decoupled from which input is selected).

MQTT topics (regardless of whether you use homeassistant or not):

• homeassistant/switch/<unique_id>/availability - online when connected to the switch; set to offline automatically as a last-will message when disconnected.
• homeassistant/switch/<unique_id>/<input number>/config - homeassistant auto config info
• homeassistant/switch/<unique_id>/<input_number>/state - 'off' or 'on'
• homeassistant/switch/<unique_id>/<input_number>/set - write 'on' to this topic to select this input

Installation

Pre-reqs:

• node 14.x on your $PATH
  • https://github.com/nodesource/distributions#deb
• npm install

Other versions of node may work, but have not been tested.

To run:

node index.js --ports n --broker foo --unique_id bar

• You must:
  • Specify an MQTT broker. Use a URL string - for example, mqtt://user:pass@ip
  • Pass a unique_id string, for use in homeassistant. Pick something actually unique for your situation!
• You may:
  • Pass the --serialport argument, otherwise /dev/ttyUSB0 is presumed.
  • Pass the --name argument; otherwise a suitable default is constructed. This name is shown in various places in homeassistant.
  • Pass the --ports argument to specify the number of ports on your switch; otherwise 8 is assumed.
• For debugging, set the following environmental variable: DEBUG='iogear'. Additional low-level debugging is available for both mqtt.js and the SerialPort libraries; consult their documentation for more info.

DietPi

I run this on a Raspberry Pi Zero; using USB hub with an ethernet adapter connected as well as a USB-to-Serial adapter. I've included a sample dietpi.txt config that you could adapt to your situation. Installation is out of scope for this document, but see the DietPi docs for more information: https://dietpi.com/docs/user-guide_installation

Notes

• My HDMI switch (an IOGEAR xxx) is actually a whitelabeled Aten VS0801HB.
  • Docs for the RS-232 protocol are here: https://assets.aten.com/product/manual/vs0801hb_um_w_2019-11-15.pdf
  • Broadly speaking, this tool should work for non-whitelabeled Aten HDMI switches as well.
• We could implement additional features if so desired. I didn't need them, so didn't do that yet.
• We tend to send more MQTT updates than is strictly necessary because the RS-232 protocol only provides a way to get the status of a current port - we could probably be a little smarter here, but it was just a lot easier to send a few extra MQTT messages.
• This is fairly homeassistant-specific, because that's what I run at home. However, I would be delighted to accept PRs that make it more generic/usable for non-homeassistant users. I just don't really know the "right way" to do things for non-homeassistant users myself! :)