Add a switch to HA without connection to a device

Hi all! I’m a beginner to Home Assistant and really not a coder. However, my husband’s put together a pretty thorough system for our house in HA, and I appreciate it even though I don’t always (okay… rarely) understand it. However, I’d like to surprise him with something: he has a home office in a room that is ideal, except that I have to go through it if I want to get to the laundry room. If he’s in a meeting or a confidential project, I can’t be going in there until he’s done. I’d like to make a switch in HA that he can toggle depending on if it’s fine for me to enter or not, but I don’t know how, or if it’s possible, to set up a switch without it being connected to a device (I’ve set up switches before, but only with for example Zigbee smart plugs). It would basically be an empty switch that doesn’t do anything except alert me to its state (after I have the toggle I’ll set up a command with Node Red to notify me when the state’s changed). If it matters, we use Lovelace UI, so I’d need to have one I can add to a card.

Can anyone tell me if this is possible and, if so, how to get it done?

It’s called an “input_boolean” and can be set up using the UI at ConfigurationAutomations & Scenes : Helpers, than “+ Add Helper” (lower right) : Toggle

Thanks a lot! Got it set up in two minutes.