Fireflies in a bottle- Skyy Vodka.

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Joined Aug 7, 2008
Random # 2 00000.jpg This is one use for a random pulse generator which uses 2 clocks, one slow, U1 & one fast, U2. When U1
output is high, About 150 millis. U2 is enabled and oscillates at about 100 kHz & stops when U1-3 goes low, leaving one output of U3 high. In a 20 sec. period, every LED flashed at least once. From past experience
using similar circuits sometimes the circuit seemed to learn and gave a repeating pattern. Using a candle LED, U4, to generate a few mV of noise at pin 5 of U2 cured the problem. U15,U16 generate a blanking pulse to
inhibit the flashing LEDs when U3 is counting.
A round circuit board is mounted to the inside of the lid of a cookie can; IC's wired dead bug style & SMT 2222's collectors soldered to a length of cu foil tape. Power is from 4 AA Alk. batteries or a 6 V DC wall wart.