Usb i/o board (based on a Microchip microcontroller featuring a usb port) allows you to drive relays and read input status, easily and at a low cost (starting from 39 euro).This board is similar to a PLC (Programmable Logic Control) yet, it receives commands from a Personal Computer using USB bus. It is easy to connect using USB because when you plug the USB to the PC, a virtual RS232 port is created so you can easily develop the application software. You can use this board for domotic application, industrial automation, etc...