First look: A prototype gaming controller designed for one-handed use is gaining traction online for challenging a basic assumption in PC gaming: that input requires two hands. The device, called the ERCHAM MK1, was developed by a Reddit user who goes by u/Adventurous_Tie_9031, or Joe. He began working on it after losing his right arm in an accident and encountering the limitations of existing hardware. Standard setups – whether a mouse and keyboard or a console controller – proved difficult to use with one hand, prompting him to design an alternative.
The ERCHAM MK1 combines mouse and keyboard functions into a single unit. It features an optical sensor that enables independent cursor control, alongside a 28-key programmable keypad. Each key can be mapped to specific inputs, giving users much of the flexibility of a full keyboard in a more compact layout.
The controller also appears to include thumb-operated controls – either joysticks or D-pads – as well as clickable scroll wheels on both sides. This layout allows the device to be used in either hand without modification, which is uncommon among gaming peripherals.
While the design draws on products like the Razer Tartarus, it goes further by eliminating the need for a separate mouse. Instead of splitting tasks between two hands, all input is handled through a single interface.
Joe said the controller is designed for "amputees, nerve injuries, RSI, stroke survivors, and anyone who struggles with a traditional keyboard and mouse setup."
The one-handed gaming controller I designed after losing my right arm just made Top 5
by u/Adventurous_Tie_9031 in pcmasterrace
The project has drawn significant interest. Joe said an earlier Reddit post about the prototype received more than a million views. That attention helped the project place fourth in the Entrepreneur of Impact competition.
Joe said that if the project wins, the funding would help accelerate development and "get this project moving faster toward production." Even without that support, he plans to continue working toward manufacturing.
Most major manufacturers do not focus on single-handed gaming hardware, leaving users who need it with limited options. By combining mouse and keyboard functions into a single device, the ERCHAM MK1 points to a different direction – one that treats accessibility as a core design principle rather than an add-on.
Whether the device reaches the market remains uncertain, but the early response suggests there is demand for more flexible input hardware – especially among users who have been underserved by existing designs.