Build a Touchpad for Drawing on Your Commodore 64 or Modern PC

The most advanced input device that most Commodore 64 users owned was a joystick, which makes it surprising that drawing software and even a GUI (Graphical User Interface) operating system were developed for the system. The first party Mouse 1351 was even released by Commodore in 1986 specifically for drawing and navigating GUIs. A third party graphics tablet called the KoalaPad was also released in 1983. It worked with the Commodore 64, Apple II, TRS-80, Atari 8-bit family, and IBM PCs. Taking inspiration from that device, Jan Derogee developed a similar drawing touchpad called Commo Pad.

Like the KoalaPad, the Commo Pad connects through the Commodore 64’s control port. While many joysticks from the era were digital and each direction was just either active or not—a setup that only allows for vertical, horizontal, or 45 degree angle lines, that port is capable of understanding analog values. The Commo Pad takes advantage of that to draw smoother lines. The Commo Pad can actually be toggled between three modes: KoalaPad mode, joystick mode, and Mouse 1351 mode. If you want, you can even connect the Commo Pad to a modern computer via a USB cable and use it like a mouse. The Commo Pad will automatically detect whether it’s connected to a Commodore 64 or PC.

The most important part of this project is, of course, the touchpad itself. In this case, it’s a resistive touchscreen overlay that is normally used in conjunction with 7” LCD panels. That is monitored by an Arduino Pro Micro board, which was chosen because it can be configured to show up as an USB HID device when connected to a computer. The enclosure wasn’t 3D-printed as you’d expect, but rather constructed from wood and then sanded, primed, and painted. If you want to do some drawing on your Commodore 64, you may want to consider using the schematics provided by Derogee to build your own Commo Pad.