ALARM SIGNALLING SYSTEM PHOTOELECTRIC DEVICE Russian patent published in 1995 - IPC

FIELD: signalling systems. SUBSTANCE: device has housing 1, light filter 2, light emitting diode 3, radiation detector 4 built around photoelectric cell 6 and band pass amplifier 5, operating signal discrimination unit 7, shielding plate 8, alarm signalling unit 9, supply unit 10, change-over switch 12, power supply source 13, pulse generator 14 and threshold controller 11. Pulse generator 14 generates short and rare current pulses which ensures lighting of light emitting diode 3. If object (human being) appears in front of eyesight, reflected radiation gets on photoelectric cell 6. Timer 16 makes operating element 17, for instance, electric bell, operate at a lapse of time τ_п+ τ_o, with element operating intermittently. Operating element 17 can be actuated by applying constant voltage directly from output of driven generator 15. Such mode can be used, for instance, when switching on illumination, if delay and intermittent operation are not required. EFFECT: enhanced reliability, enlarged operating capabilities. 5 cl, 2 dwg