A good way to compare the complexity and assembly effort of competing designs in a one-off situation is to count the number of soldered pins. All of the circuits have switch debouncing, a one-transistor LED driver, a CD4017, and two decoupling capacitors. If you factor out the common parts, here are the numbers.
#9 is the winner with 25 soldered pins but has a possible power consumption issue. The possible issue can be reduced greatly by changing to a CMOS 555.
#6 solves the power issue, but has 38 soldered pins and needs three additional resistors.
#18 has 29 pins.
#19 has 26 pins.
Changing to a CD4015 shift register reduces the pin count even more.
ak
#9 is the winner with 25 soldered pins but has a possible power consumption issue. The possible issue can be reduced greatly by changing to a CMOS 555.
#6 solves the power issue, but has 38 soldered pins and needs three additional resistors.
#18 has 29 pins.
#19 has 26 pins.
Changing to a CD4015 shift register reduces the pin count even more.
ak
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