I was working on a recent project that entailed hours and hours of monitoring the power feed on my mini mill. Well, it didn't take too long to get really old and so I started thinking about about making an "table position alert" so I could be multi-tasking while staying within reach of the mill. The next day on my way home from work I had a brainstorm and I stopped by the Home Depot and found the perfect solution, a home alarm system window module. Just double stick tape it up in place and set-up and alarm to chirp (actually sounds like you walked into a liquor store) when it reaches your limit. The cost was very reasonable at less than $10.