A method for executing a command by a swallowable in-vivo device , the method comprising: in a swallowable in-vivo device moving relative to a non-stationary three-dimensional reference frame and comprising a movement sensor configured to output movement signals having temporal and/or spectral characteristics, performing, spectrally analyzing, by a controller of the swallowable in-vivo device , a movement signal outputted from the movement sensor vis-a-vis spectral characteristics of predefined fiducial command-invoking movements stored in a memory of the swallowable in-vivo device to detect a potential command-invoking movement that is associated with a command; characterized in that the method further comprises: temporally analyzing, by the controller of the swallowable in-vivo device , the potential command-invoking movement vis-a-vis temporal characteristics of predefined interference movements stored in the memory of the swallowable in-vivo device to classify the potential command-invoking movement as a command-invoking movement or as an interference movement; executing, by the controller of the swallowable in-vivo device , the command if the potential command-invoking movement is classified as a command-invoking movement, and refraining from executing the command if the potential command-invoking movement is classified as an interference movement. in a swallowable in-vivo device moving relative to a non-stationary three-dimensional reference frame and comprising a movement sensor configured to output movement signals having temporal and/or spectral characteristics, performing, spectrally analyzing, by a controller of the swallowable in-vivo device , a movement signal outputted from the movement sensor vis-a-vis spectral characteristics of predefined fiducial command-invoking movements stored in a memory of the swallowable in-vivo device to detect a potential command-invoking movement that is associated with a command; characterized in that the method further comprises: temporally analyzing, by the controller of the swallowable in-vivo device , the potential command-invoking movement vis-a-vis temporal characteristics of predefined interference movements stored in the memory of the swallowable in-vivo device to classify the potential command-invoking movement as a command-invoking movement or as an interference movement; executing, by the controller of the swallowable in-vivo device , the command if the potential command-invoking movement is classified as a command-invoking movement, and refraining from executing the command if the potential command-invoking movement is classified as an interference movement. temporally analyzing, by the controller of the swallowable in-vivo device , the potential command-invoking movement vis-a-vis temporal characteristics of predefined interference movements stored in the memory of the swallowable in-vivo device to classify the potential command-invoking movement as a command-invoking movement or as an interference movement; executing, by the controller of the swallowable in-vivo device , the command if the potential command-invoking movement is classified as a command-invoking movement, and refraining from executing the command if the potential command-invoking movement is classified as an interference movement. <EOS>