Low Cost Dual Digital Dice
This simple dual digital dice is based on three low-cost ICs, a few transistors and a handful of LEDs. IC1a & IC1b operate as an oscillator with a frequency of about 4kHz and this clocks IC2. The frequency of oscillation is not critical - it simply needs to be high enough to prevent cheating. IC2 and IC3 are 4516 binary counters, configured to count in binary from 1-6. A power-on reset is not required here since, if the initial state is outside the correct range, the counters will count into the correct range after a few clock pulses. Let's first consider how IC2 operates. When the counter reaches "7" (ie, 111), the AND gate formed by diodes D1 & D2 and the 47kO resistor applies a high to the PE pin (pin 1). Circuit diagram: Low-Cost Dual Digital Dice Circuit Diagram This presets the counter to 1 (ie, 001) and so PE goes low again. The counter then increments in the normal manner until it reaches "7" again. Counter IC3 operates in the same manner except ...