The Battery Device Adapter is a switch adapter for toys and other battery-operated devices, designed for use by children and adults with fine motor and upper extremity disabilities. This switch adapter is an interface control that can be used to adapt any battery operated toy or other device, such as a radio or CD player, for switch operation. The user inserts the adapter between the end of the battery and the contact, turns the device on, and plugs a switch into the mini-jack port. The toy or device can then be controlled through the switch. Versions are available for double-A battery-operated and C or D battery-operated toys or devices.