DIY Digital LED Crystal Oscillator Freq Counter Meter Tester Kit Case Cable E138

Features: 
- 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 mode which automatically turns
 
- The display off if the frequency didn't change significantly within 15seconds
 
- USB 5V or DC5-12V power supply can be used