How to force sleep/force shut down a laptop after X time no matter what

Before bed, I put on some earphones connected by a long wire to my laptop and listen to audio.

I'd like the laptop to force go to sleep no matter what within say 25 minutes. Hopefully by then I will be asleep and don't want to move.

How do you do this?

Can it also be done for a tablet?

Are there smarter solutions for this? Ideally I'd like no light from the computer at all during the audio

Back in the day, I would put a cassette into sound recorder and then when it was done it was done. No blinking lights no having to worry about those things
But it is much more convenient to collect audio on a computer than a physical cassette

 

This can be done with the commandline very easily. Press your windows key (or pull up the start menu), type 'cmd' and hit enter. Then you're going to type shutdown /t xxx. More info. here.

"/t xxx = This is the time, in seconds, between the execution of the shutdown command and the actual shut down or restart. The time can be anywhere from 0 (immediately) to 315360000 (10 years). If you don't use the /t option then 30 seconds is assumed. The /t option is not available with either the /l, /h, or /p options."

 

You could also setup a scheduled task if you want it to sleep at the same time every day [Tutorial] How To Schedule Windows To Sleep And Wake Automatically

 

I typed shutdown /t 30 and nothing happened.

http://i.imgur.com/uFASA6s.jpg
http://i.imgur.com/lJYiDRz.png
What are the next things I should do?

 

Ideally, every night not at the same time I will be able to just push a desktop shortcut that will automatically sleep the computer in 30 minutes. What are the options to get this? A desktop shortcut to do everything for me no cmd and typing

Sleep slightly better than shut down.

I am not going to have the same bed time for a while.

 

I think you need shutdown /s /t 30


Once you have this working, you should be able to make a batch file on your desktop that will do the same thing. See here.