After a devastating 2021 motorcycle accident left him without the use of his right arm due to severe brachial plexus nerve damage, Joe Tomasulo refused to let his injury sideline him from one of his greatest passions: gaming.
Frustrated by the limitations of traditional two-handed setups and the shortcomings of existing adaptive hardware, the Reddit user known as u/Adventurous_Tie_9031 channeled his determination into invention. The result is the ERCHAM MK1, a custom one-handed controller that combines precise mouse tracking with a full keyboard-like array of programmable buttons — all designed to be operated fluidly with a single hand.
Unlike modified keypads, one-handed mice or foot pedal solutions that often require constant mode-switching and compromise performance, Tomasulo’s device integrates everything into one ergonomic unit. A built-in optical mouse sensor on the bottom allows users to move the entire controller for aiming and cursor control while their fingers handle movement, abilities, macros and shortcuts on a compact, 30-plus button layout. It features a stabilizing hand strap, palm rest and contoured grip engineered to reduce fatigue and provide a secure, natural hold during extended sessions.
The ambidextrous design works comfortably for either hand, and the device functions as a standard USB HID peripheral — registering to PCs as a seamless blend of keyboard, mouse and gamepad. Fully programmable with onboard profile storage, it aims to deliver the precision and responsiveness of a traditional keyboard-and-mouse setup without the need for two hands. Tomasulo has hinted at future iterations featuring analog hall-effect keys, rotary encoders and enhanced sensors for even greater versatility across gaming and productivity tasks.
Tomasulo chronicled his multi-year development process — from early Razer Tartarus modifications to more refined integrated prototypes — on Reddit communities including r/pcmasterrace, r/gaming and r/disabledgamers. His posts, complete with build videos and gameplay footage, quickly gained traction, with at least one surpassing a million views and sparking widespread interest in the gaming and accessibility communities.
While the ERCHAM MK1 was born from personal necessity, Tomasulo sees its potential reaching far beyond his own experience. The controller targets amputees, nerve injury survivors, stroke patients, individuals with repetitive strain injuries (RSI) and anyone who struggles with conventional two-handed input devices. He has particularly emphasized its ability to help disabled children overcome barriers and enjoy gaming on equal footing with their peers.
“Losing the ability to game normally was one of the hardest parts of my recovery,” Tomasulo has shared. Rather than settle for suboptimal workarounds, he set out to create a true performance device that feels natural and competitive.
Tomasulo is now pushing to move beyond handmade prototypes into full production. He has established ercham.com and launched (or is in the process of launching) a Kickstarter campaign for the ERCHAM MK1, seeking support to manufacture and distribute the controller more widely. The campaign highlights its applications in gaming, productivity and accessibility, with potential for future console compatibility.
For updates, interested parties can visit ercham.com, search for the ERCHAM MK1 Kickstarter, or follow Tomasulo’s Reddit activity under u/Adventurous_Tie_9031 for prototype footage and community discussions.
