This project reads the AC line frequency and displays on a LCD. The 120V AC is first converted to 12V AC using a step-down transformer. With the help of a BJT, the output Sine wave is further converted to 5V square pulses which is fed to TOCKI pin of PIC16F628A. The Timer0 module is used as an 8-bit counter. The counter counts the number of pulses arrived at TOCKI port in 1 sec, which, in fact, is frequency of manis AC, and displays it on a LCD.
Timer0 Counting AC Line Frequency - [Link]
Sylvain Bissonnette writes:
This is a simple project. The Frequency is passing through an op-amp to convert it in a square wave. The ouput of the op-amp is feeding the 3*8 bits counter (24 bits) who can accumulate at a maximum of 16777216 count. The maximum frequency you can measure without changing the time base of one second is 16.777216 Mhz. The ATMega8 have 3 functions: enable the counter gate at each second, read his value and display it on the LCD.
ATMega8 Frequency Meter – [Link]
In this project we are building a basic and low cost frequency counter circuit . It can measure from 16Hz to 100Hz signals with a maximum amplitude of 15V. The sensitivity is high, the resolution is 0.01Hz. The input signal can be a sine, a square or a triangle waveform.
Frequency Counter - [Link]
The device presented here can be used to count events as well as to measure frequencies and times. Most of it is built from discrete HC (high speed CMOS) logic and to be honest, if I needed to build such a device again, I would not build it as presented here but integrate things into a CPLD or a microcontroller instead. However, it was instructive not to do so and maybe it is interesting for other people as well (for what reason ever).
- Frequency measurement from 0.1Hz to ≥10MHz; gate times of 0.1, 1 and 10 seconds
- Time measurement 0.001ms to 10000s (time clock 1MHz and 1kHz): measuring L/H time or 1, 10 or 100 complete pulses or time between input A and B transition
- 5-digit LED display with display hold
- CMOS-compatible Schmitt-trigger inputs with over- and under-voltage protection
Frequency Counter - [Link]
This project will turn your multimeter into a sensitive frequency counter with a wide counting range. You can also use this project to upgrade your old frequency counter and extend the range up to 2.5GHz. This project will describe a prescaler which will work up to 2.5GHz and with very high input sensitivity. The prescaler will divide the input frequency with either 1000 or 10.000.
Poor man’s counter - [Link]
This simple design uses the 20 pin ATTiny2313 microcontroller to measure frequencies from 1Hz to over 2MHz. The frequency is displayed on a standard HD44780 16×2 LCD. A bright white text, blue backlit LCD is included with the kit. The device requires a regulated 5V power supply. [via]
FunCount Frequency Counter – [Link]
This article shows how to build a small, cheap and simple frequency meter, without any fancy, out of reach components. The simple proposed design can measure frequencies up to 40 Mhz with errors below 1%! This degree of precision will be more than enough to debug most of your analog and digital circuits, and will give you the ability to analyze many aspects that you were unable to see before.
Build your 40 MHz Frequency meter! - [Link]
This is the Frequency Counter for 100Hz-2.5GHz, using LCD 16 chara.x 2 lines ,TCXO 12.8MHz(1ppm ) and PIC16F84. The Voltage (0-510mV) of the input signal is also indicated on the LCD , therefore tuning of the coil can be conducted while checking the frequency. Furnished with IF offset-function, this can be applied for the frequncr display of the home brewed transeiver. Print circuit board size is very small of 100mm x 43mm. [via]
Frequency Counter – [Link]
Frequency counter built by Wayne McFee. This is from IK3OIL’s web site, and the cost of the counter was about $2, minus the display, which was about $7. Design and Code by Francisco IK3OIL. McFee writes:
This frequency counter was mentioned on the QRP-L mailing list. I offered to put up some more information on the counter on this web page. I have not built one (yet) nor do I have any further information than what is here.
16F84 PIC Frequency Counter - [Link]