PSEUDORANDOM_SIMULATED_FLICKER_SEQUENCER

Published:2009/7/9 1:48:00 Author:May | From:SeekIC

The pseudorandom sequencer drives a solid-state relay, If you power a low-wattage lamp from the relay, the lamp will appear to flicker like a candle’s flame in the wind; using higher-wattage lamps allows you to simulate the blaze of a fireplace or campfire. You can enhance the effect by using three or more such circuits to power an array of lamps. The circuit comprises an oscillator, IC1, and a 15-stage, pseudorandom sequencer, IC2-4. The sequencer produces a serial bit stream that repeats only every 32767 bits. Feedback from the sequenc-er’s stages 14 and 15 go through IC4D and back to the serial input of IC2. Notice the RC network that feeds IC4C; the network feeds a positive pulse into the sequencer to ensure that it won’t get stuck with all zeros at power-up. The leftover XOR gates IC4A and IC4B further scramble the pattern. The serial stream from IC4B drives a solid-state relay that features zero-voltage switching and can handle loads as high as 1A at 12 to 280 Vac.



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