Spherical robot having a driving mechanism for indicating amount of stored electric power

A robot, comprising:

• a spherical body, including:
• a spherical-band-shaped main casing where a first side portion of a sphere and a second side portion opposing the first side portion have been removed,
• a first spherical cap corresponding to the first side portion, and
• a second spherical cap corresponding to the second side portion;
• a shaft linking the first spherical cap and the second spherical cap;
• a display attached to the shaft via an arm and displays at least a part of a face of the robot;
• a first driving mechanism that causes the first spherical cap and the second spherical cap to be rotated by a rotation of the shaft;
• a second driving mechanism, independent from the first driving mechanism, that causes the main casing to be rotated, the main casing being centered on the shaft;
• an electric power source that is charged by electric power from an external charger, and supplies the electric power to the first driving mechanism and the second driving mechanism;
• and
• a control circuit, when an amount of electric power of the electric power source remaining is lower than or equal to a predetermined value while the electric power source is disconnected from the charger, controls the second driving mechanism to stop a rotation of the main casing and controls the first driving mechanism to switch a rotational direction of the first spherical cap and the second spherical cap, thereby causing the display to be reciprocally moved in a vertical direction.