As this will be using the existing Arduino IDE's Virtual COM port, it should be much easier to write than grappling with the Velleman K8055 DLL methods and procedures!. To write a simple Windows application (in Delphi) to control the 'Arduino' digital output pins, similar to the application supplied with the Velleman USB Interface. To interface the 'DIY' Arduino with either a or a - or even try both!. To build a 'minimal' stand-alone Arduino on its own PCB (. The original Video Switcher design only needed three data output lines from the PC's parallel port to selelct the cameras, so this seemed like a good opportunity to bring together a few bits and pieces and 'concepts' that I'd been thinking about for the Arduino specifically. I had in mind something similar to the but without any inputs or LEDs or buffering or Analogue IO. Although the software I ran on the PC to control the Video Switcher is beyond the scope of this article, I needed to update it to use USB instead of the parallel port. A recent failure of the PC I used to operate the Video Switcher meant I needed to find an alternative to the parallel port. Unfortunately, fewer PCs are fitted with parallel pors these days and, for a laptop, it's not really an option. Arduino and Delphi Controlling Outputs with the PC Controlling Arduino Outputs with the PC Elsewhere on my website, I show details of a which can be controlled using the computer's parallel port.