Abstract: This study reports the design of a low-cost image-based mouth switch for the people with severe disabilities. Via this mouth switch and a communication aid, people with severe disabilities can manipulate computers and communicate with other people. Two experiments were conducted to test the performance of the mouth switch. Experimental results showed that this switch could help people manipulate computers simply by opening or closing the mouth. In addition, this article also presented some relevant patents about the human-computer interfaces for disabled people.