Heart rate monitors connected to an ink plotted graph are a staple of movies and TV and they usually come in beautiful portable versions by companies such as Lafayette Systems, making them a classic spy suitcase gadget.Polygraph lie detectors are widely believed to be useless quackery, no more effective than a Scientology Dianetics machine, but they are commonly used by law enforcement and government agencies, usually in the US and are an anachronistic cultural legacy of the cold war.Today, the classic analog polygraph is being replaced by much less interesting computer versions.