Smith D G
J Clin Eng. 1981 Apr-Jun;6(2):131-2. doi: 10.1097/00004669-198104000-00010.
This paper describes a low-cost environmental control system for quadriplegics. With a single custom designed input switch, a disabled patient can turn up to three electrical devices on or off. The design could easily be extended to handle additional devices. The system can be constructed in one day for approximately $40.00 in parts cost, plus the cost of labor.