This is a PCB circuit using LM555 integrated circuit to blink 2 sets of 8 LEDs.
Important parameters: VCC = 5 V, R1 = 4.7k ohm, R2 (potentiometer) = 20k ohm, C1 = 47 micro Farad.
R1, C1 are size 1210. LEDs are size 1206. R2 is 3314J. 555 timer is LM555CM. Micro USB B female smd.
PCB size 12cm by 12cm.
Calculations:
When R2 = 0 ohm, Frequency f = 6.519 Hz, Period T = 0.153 s, Duty cycle = 100 %.
When R2 = 20k ohm, Frequency f = 0.685 Hz, Period T = 1.459 s, Duty cycle = 55.257 %.