Passive infrared detector of upward thermal air currents - gives indication of proximity of thermal by difference in time of lighting of detector-driven LEDs

摘要

The infrared detector (5), screened as necessary, is rotatable on a pivot (7) and its positive and negative outputs are amplified (11) separately to drive LED indicators (12, 13). As a thermal is approached and the scanning angle increases, the interval between lighting times of the LEDs also increases. The time difference is measured electronically (14) and an acoustic signal is given (15). Automatic direction-finding is possible with another electronic circuit (16) controlling the pivoted support (7). USE/ADVANTAGE - On e.g. sailplanes, thermals are located at sufficient distance with display on approach to assist in finding favourable course.