PCB and components

PCB is common for counter and digital scale:
It is TWO SIDE COPPER PCB!

pcb

Components placement (digital scale has a few ones, which aren't necessary for counter):

components

Notes:

  • PCB is the same for both common cathode and common anode variant (copper foil must be broken at both sides of transistor array and vired with +5V in case of common anode variant.
  • common anode switching transistors are of PNP type (best solution is to take low power switching transistors),
  • resistor from pin 3 of decoder 4051 should be grounded,
  • source code should be slightly changed (Changes are in the source code commented. You should uncomment them and comment "cathode" blocks.)
  • Digital scale differs only in components it needs. For reference see schematics.