“Frequency counter (reciprocal)
Gate time selectable from 0.1 second up to 60 seconds
Frequency range from 0.1 Hz up to 10 MHz (tested)
Input 3.3V and 5V safe
Uses a STM32F103C8 (Blue Pill) and 16x4 LCD
Supplies:
STM32F103C8 (Blue Pill)
16 x 4 LCD screen (HD44780 compatible)
10 MHz OCXO
74HC74
74HC00
3.3V voltage regulator
rotary encoder with button
some resistors, capacitors and diodes
perfboard
project box”