With the continuing manufacture of new computers, there is a clear and obvious trend of the parallel port becoming less and less common. For our younger readers; the parallel port is an interface standard used for bi-directional communication between a computer and a variety of peripherals. The parallel port’s demise is partially due to the invention of the USB standard.
If tinkering with CNC Machines is one of your hobbies then you are familiar with the parallel port interface being fairly popular for CNC control board connections. So what do you do if your new fancy computer doesn’t have a parallel port but you still want to run your CNC Machine? Well, you are certainly not stuck as [Bray] has come up with a USB to Parallel Port Adapter solution specifically for CNC use.
A cheap off-the-shelf USB to DB25 adapter may look like a good idea at first glance but they won’t work for a CNC application. [Bray's] adapter is Arduino-based and runs GRBL. The GRBL code is responsible for taking the g-code commands sent from the computer, storing them in a buffer until they are ready to be converted to step and direction signals and sent to the CNC controller by way of the parallel port DB25 connector. This is a great solution for people needing to control a CNC Machine but do not have a parallel port available.
[Bray] is using a Raspberry Pi running GRBLweb to control his adapter board. However, there are other programs you can use to communicate with GRBL such as Universal G-Code Sender and GRBL Controller.
The board has been created in Eagle PCB Software and milled out using [Bray's] CNC Router. The design is single-sided which is great for home-brew PCBs. He’s even made a daughter board for Start, Hold and Reset input buttons. As all great DIYers, [Bray] has made his board and schematic files available for others to download.