This document describes the construction of small frequency counter with a cheap PIC microcontroller and a few seven-segment LED digits. Frequency range 1 Hz ... 50 MHz Five digits resolution (display for example x.xxxx kHz, x.xxxx MHz, or xx.xxx MHz) Measuring signal amplitude can be up to 30 v 4-40 m passive crystals can measure Automatic range switching with different gate times Optional addition or subtraction of a frequency offset (programmable) Very low component count: a PIC 16F628, 5 7-segment LED displays, a 20MHz crystal and a few resistors Optional (configurable) power-saving which automatically turns If the frequency does not change significantly within 15 seconds, the display turns off Can use USB 5V or DC5-12V power supply Package Includes: 1x DIY kit 1 x USB Cable