Schematic
DICER-S6
is our automatic LED-DICE kit. It's based on
“10 bit counter.” Using the LM555 as a random clock generator, it increases the 10 bit counter
randomly--therefore light arbitrarily sequences of LEDs. Since we wire pin 5 to the
counter RST (reset) pin (pin 15), when the counter reaches the fifth
position it automatically goes back to the first position on the
next pulse.
R13
to R16 resistors determines the LEDs brightness and limits the
current flow to about 10 to 15mA when running between 9V to 12
VDC corresponding.
R5
to R12 resistors determines the minimum transistor forward
base-current sufficient to turn the transistor on. At
given time only one random output of the counter (U2_Q0 to
U2_Q5) is "On" ("1"), and since Q5 is PNP transistor,
and Q2, Q3, Q4 are NPN transistors: U2_Q5
= "1" --> Transistor Q3 = "On",
Transistors Q2, Q4, Q5 = "Off" --> Dice = 1 (L4 Light)
U2_Q1
= "1" --> Transistor Q5 = "On",
Transistors Q2, Q3, Q4 = "Off" --> Dice = 2 (L1, L7
Light)
U2_Q2
= "1" --> Transistor Q5, Q3 = "On",
Transistors Q2, Q4 = "Off" --> Dice = 3 (L1, L4, L7
Light)
U2_Q3
= "1" --> Transistor Q2, Q5 = "On",
Transistors Q3, Q4 = "Off" --> Dice = 4 (L1, L2,
L6, L7 Light)
U2_Q0
= "1" --> Transistor Q2, Q3, Q5 = "On",
Transistors Q4 = "Off" --> Dice = 5 (L1, L2, L4,
L6, L7 Light)
U2_Q4
= "1" --> Transistor Q2, Q4, Q5 = "On",
Transistors Q3 = "Off" --> Dice = 6 (L1, L2, L3,
L5, L6, L7 Light)
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