I would like to use a TV or other screen as a second monitor, not as a mirror, but a fully separate monitor the way it would work with an HDMI cable.
I usually use an HDMI cable for this but I'd like to be unattached and move freely. I travel frequently and this would be very useful for me to not have to carry around a long cable with me everywhere. Something like the Chromecast would work, but it requires extra software as far as I know to be used as a full separate extended desktop.
I don't know if this is possible, and am happy to buy some kind of dongle if it exists.
The closest I know how to get to this currently is using the Chromecast dongle, which allows you to either cast a tab, application or your desktop (mirroring). Unfortunately it doesn't function as a fully separate desktop/monitor, so this isn't quite what I'm looking for.
Best Answer
I assume that you are using a MacBook. If so, you can do it with an an Apple TV box, but since it works over WiFi, you will need to connect the AppleTV to the WiFi network. Use an HDMI cable to connect it to the TV. Then use Airplay on the McBook to connect wirelessly to the AppleTV and select "Use as separate display".
It would be much cheaper and easier to just use an HDMI dongle on the MacBook (mini display port, USB or USB-C depending on the model MacBook) and an HDMI cable to the TV.