Once upon a time, though a circuit of this type of calling Searches Banim made with Microchip PIC Series devreydi 6 pcs rörele control pcb computer program code can be done via usb port usb drive and 9-12 volts AC regulated power supply section of the circuit’s schema files on the SPI and RS232 connections have.
In fact, for the computer to control the relay with simple circuits, there are cheaper, but ( the computer and the Device Control ). Although these circuits relays computer is turned off momentarily to his questioning of the port leaves the microcontroller used in the system prevent this problem can only be undertaken.
USB Relay Card
Applied Projects List
BaseKit Xilinx CPLDs
VGA monitor tester
8bit μC GraKa
ARM
ARM SD MMC
μClinux 4 ARM
ARM Webbox
LPC22xx Board
Pal Video & OSD
LPC213x + ENC28J60
For more detail: Control Relay Card with USB port Atmel using Atmega8 microcontroller