It should not be difficult to reverse engineer it and make something that can detect people that can be invisible or move quicker than one can see. We are in luck as I do have the vest with me here, it was a gift along with my house when it was brought here. I can desconstruct the vest and begin reverse engineering it in the event I cannot find my original notes on the subject.
Do you suggest this be done in addition to the electromagnetism detector? It cannot hurt to have more than one way to detect someone who may otherwise go unnoticed.