A remotely activatable capsule. The capsule includes a housing that can be swallowed by a subject, an electrical energy reservoir having a first terminal and a second terminal positioned in the housing, a remotely activatable switch positioned in the housing and configured to be remotely activated, and a function-specific mechanism positioned in the housing and electrically coupled to the remotely activatable switch and to the electrical energy reservoir and configured to perform a function when the remotely activatable switch is activated.