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Converting a Commodore PET into a USB docking station

Arduino TeamJuly 22nd, 2022

The Commodore 64 is one of the most iconic computers of all time and it is Commodore’s best known model. But Commodore made many other well-loved models, including the VIC-20, the Amiga, and the PET. The Commodore PET 64, which Commodore released late in the model range’s life for educational use, was Dave Luna’s first computer. Sadly, it bit the dust sometime in the ‘90s and Luna was never able to revive it. In 2005, he attempted to convert it into a PC, but never completed the project. Older and wiser, Luna was finally able to give the PET new life as a docking station.

Docking stations come in many forms with many different purposes, but the general idea is always to expand a laptop’s (or tablet’s) capabilities. In this case, it turns the connected laptop into a desktop experience with a dedicated screen and a full tactile keyboard. The keyboard wasn’t actually very good in the Commodore PET 64, but Luna has plans to upgrade it with a MechBoard64 to keep the original look with modern high-quality mechanical keyswitches. As it stands, the PET 64’s keyboard connects to the docked laptop and a 12” TFT LCD screen (in place of the PET 64’s original CRT monitor) acts as a second monitor for the laptop.

The screen connects to the laptop through a WAVLINK USB 3.0 DisplayLink adapter, but the keyboard connection is more complex. Because the PET 64 was an all-in-one computer, the keyboard interfaces directly with the mainboard in a manner similar to today’s laptops. There is no USB interface or standardized output at all. For that reason, Luna had to create his own adapter. He used an Arduino Micro to scan the keyboard matrix’s rows and columns looking for key presses. When it registers a key press, it sends the corresponding character to the connected laptop via the USB connection. The Micro appears as a standard USB HID keyboard, so it doesn’t require any special software.

The result is a functional laptop dock in a vintage Commodore PET package.