optical indication for the movement detector

7-62 — elektor july/august 1981 optical indication for the movement detector This circuit is intended as an extension to the movement detector which was published in the March 1981 issue of Elektor, in the sense that it adds a flashing mains lamp to the original circuit, while keeping the remainder of the circuit isolated lb from the mains. Figure la gives part of the original circuit as used then voltage divider R19/R22. T activates the relay so that, for instance, a lamp can be illuminated. With the addition of the few com- ponents shown in figure lb, the lamp can be driven by a triac and, at the same time, will operate as a flashing lamp. The flasher circuit itself consists of only one component: the flashing LED (Siemens type LD 599). A zener diode and the LED of an opto-coupler have been placed in series with the 81521 a for controlling a relay. When the detector detects onor via the s turned st some movement, transistor T3 is flasher. When transistor T3 now turns on the LE...