Altitude sensor providing audible warning to parachutist - has hand driven by barometer capsule with reflective surface moving to couple LED and phototransistor

摘要

A barometric capsule provides a signal as a parachutist passes through a predetermined altitude at which parachute should be opened. A vibrator is activated to produce audible sound. A hand in a barometric capsule has a point (25) which passes over a photocoupler (30) when the required altitude is reached. Radiation from a luminescent diode (30a) is reflected from the pointer to a phototransistor (30b) whose emitter current triggers a thyristor (32). The thyristor provides a return path for battery (40, 41) current through a sound vibrator (5). A connector (51) permits disconnection of battery current and a press button (35) allows the warning to be switched off during landing.