Lie detection One recent instrument using cognitive chronometry for this purpose is the timed antagonistic response alethiometer, or TARA. Brain-reading uses fMRI and the multiple voxels activated in the brain evoked by a stimulus to determine what the brain has detected, and so whether it is familiar. People often evaluate lies based on non-verbal behavior, but are quick to place too much merit in misleading indicators, such as: avoidance of eye contact, increased pauses between statements, and excessive movements originating from the hands or feet. Non-invasive lie detection using non-verbal behavior is performed by the Silent Talker Lie Detector. Silent Talker monitors
Flame detector detectors have an (automatic) detector window self test, but this self test only monitors the occurrence of water or ice on the detector window. A salt film is also harmful, because salt absorbs water. However, water vapour, fog or light rain also makes the sensor almost blind, without the user knowing. The cause is similar to what a fire fighter does if he approaches a hot fire: he protects himself by means of a water vapour screen against the enormous infrared heat radiation. The presence of water vapor, fog, or light rain will then also "protect" the monitor causing it