Hardware Secrets learns you how to build circuits using the PC parallel port.
The computer parallel port is the easiest way to control devices outside the PC, like LEDs, lights and even home appliances. In this tutorial we will teach you how to use the computer parallel port to control circuits outside your computer.
The greatest thing about printers nowadays is that they use USB connection. Thus, on the majority of modern PCs the parallel is not used, so it is available for us to use it to control circuits outside the computer box.