I have to thank my readers for reading this blog and commenting and i’ll try not to let you down.

Also thanks to my fellow bloggers that helped me along the way:

• Circuit-projects.com
• Electronics-lab.com
• Embedds.com
• GeeksInside.com
• HackedGadgets.com
• ScienceProg.com
• Uchobby.com
• Zedomax.com

Stay tuned, there are some great projects coming up.

You all know that opto osolator boards are used to pass signal between circuits without connecting them electrically. They are great for eliminating noise problems, or to connect circuits that have different voltages.

The opto isolator is very easy to use. Since it just passes signals through it, you just hook it up between the two different devices you want to communicate. Additionally, you will need to properly hook it up to each devices power supply. The device is intended to isolate the circuits electrically, so each side needs to be powered independently.

Opto Isolator Board For General Use: [Link] – [via]

This schematic is ment to digitally display the output of an electronic Swissflow SF800 flow sensor. This sensor puts out an open collector square wave signal (like a fan RPM monitoring signal) between 50Hz (=0.5 liter/minute) and 2000Hz (=20 liter/minute).

By dividing the measured frequency by 10 and putting the decimal point at the right place you get directly a display in liter/minute. I don’t use the first digit output (output D) from the 74C925 to obtain a display of 10 to 9990Hz or xx.x liter/minute.

3-Digit Frequency Meter: [Link]

Mobile infrared electronic transmitter

Choose one key on your remote controller (from tv, video or similar), memorized it following a simple procedure and with that key you will able to turn ON or OFF any electrical device you wish. So, with every short press of that key, you change the state of relay in receiver (Ir-switch).

Memorizing remote controller key is simple and you can do it following this procedure: press key on Ir-switch and led-diode will turn ON. Now you can release key on Ir-switch, and press key on your remote controller. If you do that, led-diode will blink, and your memorizing process is finished.

IR – relay control: [Link]

Connecting a LCD display to the end of a printer-cable is a simple and effective way of providing additional functionality to your computer system. The printer-cable LCD can be mounted on your computer case or fitted inside a Jiffy-Box and displayed somewhere away from your case. Even the fully functional software interface is simple to install and configure. The parts used are a non-backlit 16 x 2 character LCD and a parallel port cable(printer cable).

LCD Display Controlled From A Computer Trough The Parallel Port: [Link]

ATMEGA8 DevBRD is an open source development board for the Atmel ATmega8 build especially for Linux users. The board is well suited for beginners who just want to start learning the avr programming but also for advanced users who want to use it as an MCU board.

ATMEGA8 DevBRD: [Link]

The circuit seems to be very popular because it is so simple and still has a very useful and practical application and It is considered by some the perfect circuit to get started with AVR microcontrollers.

This thermometer can be used as a standalone thermometer with LCD display or it can be read out with a PC running Linux, Windows, MacOSX or solaris. BSD Unix and others are probably also possible to use for reading the temperatures. No special drivers are needed.

Simple Digital Thermometer: [Link]

The author spend 4 months coding everything from scratch. The result was however worth the effort. This new programmer works flawless and it’s a diy project. The programmer firmware has no device dependent data. Therefore it works for almost any AVR microcontroller on the market and possible future microcontrollers.

This USB programmer can be build from scratch without the need of another programmer to load the initial firmware.  The firmware is open source and programmed in C according to the AVR068 specification from Atmel.

AvrUsb500 – an open source Atmel AVR Programmer: [Link]

This is a small ajustable clock, I made based on PIC16F84A microchip.The hardware part is very simple because it only uses 74hct238 demultiplexer, 4×7 segments, and some rezistors. The software part is programmed through a device connected to serial port with icprog and made/debuged with MPlab.

Digital Clock Based On PIC16F84A: [Link]

The Digital thermometer was built by using the temperature sensor LM35DZ, PIC16F877 microcontroller and MAX232 IC. Temperature measurements can also be viewed on a computer program which can monitor the state of COM ports of a PC. Sample measurement data received through COM2 is being viewed on the SERIAL WATCHER program which is distributed freely on the internet.

Digital thermometer: [Link]