OObject has a fantastic online gallery of vintage analog ‘lie detectors’ – exactly the type of kit you used to see in old detective films where the police questions would lead to frantic activity on the polygraph as a bead of sweat would run down the perp’s face.
It has everything from a tiny 1920s original MacKenzie-Lewis polygraph to the lie detector in a suitcase Pentograph from the 1980s
Despite polygraph-based lie detectors being rubbish at detecting lies, they’re still admissible as evidence in some US states and widely used by the security services.
Link to gallery of vintage lie detectors (via BB Gadgets).
Mind Hacks 