Last Tested: Dec 9, 2019
You can only put a dashboard on a TV if the streaming service you use will allow you to log in to Looker. This isn't possible with a Raspberry Pi or Airtame since they only take a web address and don't let you navigate or use any input.
The options here are public look or SSO embed.
As of Looker version 6.24, content can be made public but restricted by IP address - so a public look could be made accessible to the Raspberry Pi's IP address and prohibited for all others.
Looker doesn't have the notion of public URL for dashboards, and probably never will since you can achieve the same using SSO embed. Just have the raspberry Pi web server generate an SSO Url with a particular embed user configuration and you're done.
Presumably, the Looker content they want to display on the TV screen will need to be refreshed periodically (dashboard refresh?). It's recommended that the Raspberry Pi device generate a new SSO URl periodically as well, perhaps daily.
This content is subject to limited support.