security device

Exploration Stage: Spring Mill
From: Miller
Description: The door is locked, but it doesn't hurt to install a device that will alert you if a troll tries to escape with the stolen bag. There is a specially made security device somewhere. Help me find it and install it.
Completed: This is what I was looking for! I often store my crops in the waterwheel shed, so I have this device set up for the winter to protect them from thieves. If a thief turns the knob, the alarm bell will ring and block the door.