How often you get involved with the frequency counter? Do you know that the frequency counter is designed for radio frequencies (RF) are common and operate on the same principles as lower frequency counters did?

Normally, they have more range before they overflow and for very high frequencies, many designs are use a high-speed prescaler to bring the signal frequency down to a point, where normal digital circuitry can be operated.

The frequency counter that you’re about to build here is a basic and low cost frequency counter circuit, where it can measure from 16Hz to 100Hz signals with a maximum amplitude of 15V. The sensitivity is very high and the resolution is 0.01Hz. For the input signal, it can be a sine, a square or a triangle waveform!

The accuracy of a frequency counter is strongly dependent on the stability of its time base. Those highly accurate circuits are normally used to generate this for instrumentation purposes, and it is usually using a quartz crystal oscillator within a sealed temperature-controlled chamber known as crystal oven or Oven controlled crystal oscillator.

When the frequency doesn’t need to be known to such a high degree of accuracy, simpler oscillator can be used for the purpose. Furthermore, it is also possible to measure frequency by using the same techniques in software in an embedded system.

Since there are many people begin to pay attention to the global warming, and they’re opted to go green, it is a great chance to get you approaches with this incredible Solar Recorder.

For your information, this solar recorder is a very useful electronic gadget, which you can use it to store data to a compact flash memory card. Oh, you said that you don’t need a solar recorder here? Well, take it easy, as you still can see by yourself how the actual steps to store data to compact flash from a PIC microcontroller.

Basically, solar recorder is a handy device that can be used for measuring daily insolation. You might need to use the PIC18F458 and the 128MB Multimedia Memory Card (MMC) to build this stuff! The solar radiation is well measured by a calculator solar cell. Read more »

The Thanksgiving have passed by, and if you’re feeling bored sitting in your house for by doing nothing, then you might want to try something more fun and interesting project!

Well, it’s not too hard to buy a humidity and temperature sensor on the market, but you need to spend over $30 or more for a simple sensor and it definitely didn’t worth at all!

Instead of pulling the money out from your pocket, why don’t you keep the money warm inside your wallet, by simply build your very own digital humidity and temperature sensor?

Since most of the components that being used here are mainly cheap, thus you don’t need to spend too much for constructing a cheap digital humidity and temperature sensor. This is going to be a very compact data logger that using the SHT11 or SHT15 sensor for humidity and temperature.

For your information, the logger will contain 128Kbytes of memory for logging 32768 samples of temperature and humidity or 26214 samples of temperature. The AT90S8535 will be the main heart of this project and it has eight 8-bit analog to digital converters built in.

If you having a job that always require you printing all those company’s bargraph all day long, then you must be very interested about this Contre-Bargraph gadget!

For your information, this cute little smart library will allow you to generate up to 8 special characters for the HD44780 compatible alphanumeric LCDs, then you can use them to print the bargraph whatever you want.

Basically, the idea is to use 8 special characters to create pseudo-graphics on an alphanumeric matrix 16X2 LCD. The pseudo-graphics you’re about to generate here represent a 16-char bargraph, which it is originally used in a simple boring project that involving temperature measurement and PIC16F877.

By the way, you need to have a LCD driver to provide the main LCD functions, because the bargraph code only uses the ‘set cgram address’ and ‘write’ commands. This LCD lib uses delay functions that should be provided somewhere by your compiler or toolchain as an example or a lib.

Also, please remember that the driver itself has to use chip-specific functions, where it’s the least portable part here.

Lastly, most of the comments are in doxygen format, therefore you just need to configure and run it in the lib* directories to have a quick documentation!