Assistant is one of the most convenient ways to control lights, plugs, and appliances around the house. The digital helper has gotten better over time, with the addition of routines, which can even be scheduled. Sadly, there's still no native option to program specific tasks, despite the fact that Google is working on adding this functionality soon. If you can't wait for official support, this third-party tool lets you schedule commands but it will require a lot of extra work.
Timer for Google Assistant by wiseindy will let you use Assistant to schedule tasks to execute after a specific amount of time. For instance, you'll be able to say "turn the lights off in 15 mn" for them to be switched off after the specified duration. Unfortunately, since this is a third-party solution, you'll need a lot of pre-work to achieve this.
The project relies on IFTTT, as well as an always-on Node.js server to function. Indeed, instead of communicating directly with your appliances, your request will go through IFTTT, which will itself send an HTTP request to your server. The latter will turn the device on and patiently wait for the specified amount of time to then make another request to IFTTT, asking Assistant to turn it off.
In addition to being relatively complex, this method means you'll have to set up each command individually and say them exactly the way they were initially written them for them to work. Even if you're fine with these letdowns, relying on so many different services might mean one of them could fail at some point, creating additional frustration. Thankfully, the documentation provided is helpful to set up the project, and its open-source nature makes it easy to adapt to your needs.
If you're not willing to bother with all these steps, you'll be happy to know Google is officially working on supporting scheduled commands, but you'll have to be a little more patient for them to come.
- XDA Developers