If you’ve ever had the pleasure of owning a Sega Dreamcast, you probably remember the quirky VMU (visual memory unit). Like on the Nintendo 64, the Dreamcast VMU was a memory card for storing save files that fit into the controller. Unlike Nintendo’s offering, the Dreamcast VMU had a small LCD and buttons to let you visually navigate those files without touching the console itself—or even the controller.
But, the VMU didn’t just store save files. It could also act as an auxiliary screen during console gameplay, or as a mini standalone handheld console. A handful of games and mini-games were developed for it, but Wermy at sudomod wanted more, so he set out to turn it into a RetroPie handheld. The VMU is very, very small, so that was far easier said than done.
First, Wermy stripped the VMU down completely, saving only the part of the PCB used for the buttons. He then took a Raspberry Pi Zero W, and removed all of the ports except for the SD card slot. That was crammed into the VMU case along with a 1.44" SPI color LCD, an Adafruit I2S sound module, an Adafruit LiPo charger and 500mAh battery, a speaker, and a couple of tactile switches.
It’s remarkable that Wermy was even able to fit all of those components into the VMU case, but he didn’t stop there. By keeping the original VMU connectors, he was able to get it working with a Dreamcast controller modified with an Arduino Pro Micro. When the VMU is plugged into the controller, it’s playable with all of the full-size buttons. A second, much larger, battery also charges the VMU battery during play, allowing for long RetroPie gaming sessions.