Electronic dice with real pips: 555 + CD4017 + diode logic
Open in the lab ▸Make my own copy
Hold ROLL and a 555 spins a CD4017 through six states about 20 times a second, far too fast to follow. Let go and it stops on a random face. The 4017 counts 0–5 (Q6 resets it), and eleven 1N4148 diodes turn each count into a real dice pattern on seven LEDs, and four BC547s do the heavy lifting (a 4017 output can only give a few mA): • the centre pip is on for 1, 3 and 5 • one diagonal pair for 2 to 6 • the other diagonal pair for 4, 5 and 6 • the middle pair only for 6 Each pair of LEDs is in series, so every group needs only one resistor and one transistor.
What is on the bench
74 parts, 101 wires.
| Resistor | 11 |
|---|---|
| Signal diode | 11 |
| LED | 7 |
| NPN transistor | 4 |
| 9 V battery | 1 |
| 555 timer | 1 |
| Electrolytic capacitor | 1 |
| Ceramic capacitor | 1 |
| Push button | 1 |
| CD4017 decade counter | 1 |
Put it on your page
The project runs live inside the frame: readers can press buttons, turn knobs and read the meters.
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Link
https://zencircuitlab.com/p/zcldice7led
Published by its author under the lab's community terms: it may be opened, copied and changed by anyone. Simulation results are for learning; check a real build against the parts' datasheets.