This is a small, off-the-shelf, DIY digital tachometer that uses a photo-interruptor (IR emitter/detector) to keep track of the RPM of anything. It’s a simple yet very effective design that I thought you might like. The RPMs of a desktop computer fan are tracked as an example with this system.
Build A Digital Tachometer / RPM Counter – [Link]
This is 60 MHz frequency meter / counter for measuring frequency from 10 Hz to 60 MHz with 10 Hz resolution. It is a very useful bench test equipment for testing and finding out the frequency of various devices with unknown frequency such as oscillators, radio receivers, transmitters, function generators, crystals, etc.
10Hz – 60MHz Frequency Meter / Counter – [Link]
If you have a blog or any other kind of website then this is for you. It’s a little box that connects to the internet and displays how many visits you have on your website. It’s designed to work independently of your computer, connecting directly to the internet via your router. Mine even steals power from one of the routers USB ports.
EGO BOX: a physical website visits display – [Link]
This is a single digit up counter based on CD4518 (Dual decade counters) and CD4543 (BCD to 7-segment decoder) ICs.
Single Digit Up Counter with CMOS ICs - [Link]
This article discuss how to use the 16bit timer on Atmega328.
Atmega328 has one 16 bit timer which is more powerful comparing to 8 bit timers. 16 bit timer is called Timer/Counter1. Counter1 has twice more bits than 8 bit Counter0, so you get more counts leading to longer duration and more precise timings.
Programming 16 bit timer on Atmega328 - [Link]
This article discuss about the AVR Timers – Counters. Timers are versatile for all timing dependent tasks like measuring time periods, generating PWM signals, generating output signals and timed interrupts. Timers run independently from AVR core. Once set, they just do their silent job while AVR can do other tasks or simply go to sleep. Read more on the link below.
AVR timers do more than count time – [Link]
Many microcontroller applications use time as their variable. For example, generating signals, keeping record of date and time, serial data transfer at a specific rate, etc. So, a microcontroller needs to have some internal resource to accurately measure time. One such resource is a hardware timer module, which is an independent binary counter that runs freely while the microcontroller is executing the main program. Each PIC microcontroller has at least one basic timer module called Timer0. This tutorial describes the Timer0 module and how to use it for precise time related application.
Tutorial on PIC timers and counters - [Link]
Josh at imsolidstate.com build a 9 digit pulse counter based on MC14453 3-digit BCD counter from ON semiconductor. A pulse counter is a circuit that counts the number of pulses arriving at the input of the circuit. Results are displayed on 7-segment displays. Many of these chips can be connected together to build a counter with as much digits as you like. Read circuit description on the link below. [via]
Build a 9-digit Pulse Counter - [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]