We’ve covered the Insteon TriggerLinc to detect when doors and windows are opened, but some people may find even the relatively small devices obtrusive on door and window frames.
A relatively new device in the Insteon arsenal is the Insteon Hidden Door Sensor. It’s a sweet little device that’s basically the size of a jumbo crayon, which you install by drilling a 3/4″ hole in a door frame (or, if the frame is metal, into the door itself):
The device operates on a single AA battery, and has a simple button on the end that gets pressed when the door is closed to trigger those open/close events.
To utilize this device via the ISY-994i, you’ll need to install the latest beta firmware from Universal Devices, as support for the hidden door sensor isn’t in the current official firmware.