From pin 3 of
Burst Timer
From
Reset
Button
a.
1 16
2 15
1 16
Score Counter (units)
3 14
2 15
3 NC
NC 13 1c R13
5 12 1b
1f 6 11 1e
1g 7 10 1a
8 9 1d
5 output
1 output
0 output
2 output
6 output
7 output
3 output
Negative
4 13
4017
5 12
6 11
7 10
89
Positive 5V–15V
Reset (when high)
Clock input
Inhibit (when high)
Carry
9 output
4 output
8 output
b.
18
1 16
2 15
3 NC
NC 13
NC 12
27
Score Counter (tens)
Negative
Trigger
Output
Reset
555
36
45
Positive 3V–15V
Discharge
Threshold
Control
2c
R14
2f 6 11
2g 7 10
89
R15-R22
1g
1a
1f
1b
2b
2f
2a
2g
2b
2e
2a
2d
R23-R28
c.
Clock input
Inhibit (when high)
Display Enable (when high)
1 16
2 15
3 14
4 13
1c
1e
1d
Display Enable output
Carry 10 output
Output to f segment
Output to g segment
Negative
4026
5 12
6 11
7 10
89
Positive 5V–15V
Reset (when high)
Special output
Output to c segment
Output to b segment
Output to e segment
Output to a segment
Output to d segment
2d
2e
2c
d.
C
R13 and R14: 10K / R15–R28: 1.5K
Score Counters: 4026 type
OR output
Input
Input
Input
Input
(Unused)
Negative
1 14
2 13
3 12
4078
4 11
5 10
69
78
Positive 5V–15V
NOR output
Input
Input
Input
Input
(Unused)
e.
F
g
a
f
b
b
f
a
g
c
e
d
Neg
Neg
d
e
c
D
Game Start
button
a. 4017 decade counter.
Reset and Inhibit pins
are normally grounded.
b. 555 timer
c. 4026 decade counter
with decoded 7-segment
display outputs. Reset
and Inhibit pins are nor-
mally grounded; Display
Enable should be positive.
d. 4078 8-input
OR/NOR gate.
e. Kingbright DC04-
11PBWA/A (blue) or
DC04-11EWA (red) dual
digit numeric display.
Game
Timer
Mole-zapping
button
NOR gate
output
Burst
Timer
Flash
Timer
Fig. C: Lower half of schematic. Connect hookup
wires between counter pins and display pins that
have the same labels. Fig. D: A breadboarded prototype. Next step: Shift the components to perforated
board and solder them into place, and mount push
buttons and LEDs in an enclosure. Fig. E: This pulse
diagram shows how the chips communicate. “Up”
pulses are positive. “Down” pulses are negative.
Fig. F: Pinouts of the chips used in this project.
All components are viewed from above.
E
Make: 143
M_140-144_LE_F4.indd 143
7/16/10 9:04:41 AM
