1. You can get padlocks & even handcuffs with timers on them, some of them are pretty heavy duty, if you don't want to make a trip to the hardware store you can order delivery online.

[![enter image description here][1]][1]
[![enter image description here][2]][2]
[![enter image description here][3]][3]
[![enter image description here][4]][4]

Combined with a strong cellar door (or a heavy duty steel security door if you must) & there really shouldn't be a problem. Just be sure you put all the tools out of the room before locking yourself in.

None of that stuff is particularly expensive & is all pretty easy to get hold of.

2. The other really obvious precaution is to have **really** big pig-out the day before the night of the full moon, when I say 'big' I mean unreasonably humongous, that's stomach stretching "I'm in no condition to do anything but lie here & be very still in case I hurt myself" huge.

You've said they're psychologically like ordinary wolves during this time & wolves don't hunt when they're stuffed.

3. Drugs, off the shelf sleeping pills & whatever else they can get hold of so they sleep through the full moon, a helpful doctor friend (or relative) might be good but so much of this can just be bought online & delivered by post that it really isn't isn't necessary.

A practical knowledge of wild herbs can also stand in for this.

4. And finally something topical, "social distancing", go camping.

Make sure you're over a day's journey on foot from the nearest people before the full moon & that you've no other means of transport to hand.

*Of course you can combine all four of these with a good solid concrete bunker somewhere in the wilderness miles from anywhere.*

**Edit :** A timed lock for the medieval era 

*You might not think timed locks are very likely or easy to come by in a medieval setting.* 

You'd be wrong ;p

There is clockwork of course but I'd go for a crude water clock.

First find yourself a cave, then you need a big rock (too heavy to move unaided & big enough to block the cave), now you need rope some wooden pit props a source of water & something to sling your rope over, this all needs to be outside the cave.

  [1]: https://i.sstatic.net/xQ3y4.png
  [2]: https://i.sstatic.net/liVNN.png
  [3]: https://i.sstatic.net/gu8BU.png
  [4]: https://i.sstatic.net/8qBGY.png