Apparatus erasing blackboard through areas

An apparatus erasing blackboard having electronically defined areas, comprising:

• a writing board, said writing board being electronically divided into board areas horizontally;
• a plurality of gears, said gears being located at two sides on a top of said writing board, said plurality of gears having a track set between said two sides;
• a belt, said belt circling said gears;
• a plurality of position sensors, said position sensors being set on said track and electrically connecting to each border of multiple respective borders of said board areas, said position sensor sensing a position trigger signal at said border of said board area, said position sensor sending a feedback signal to a single chip according to said position trigger signal to drive a motor;
• a slider, said slider being assembled on said track, said gears being driven by said motor to be rotated to carry said slider by said belt to slide along said track to be moved to a designated one of said board areas;
• an expansion part, said expansion part comprising a first expansion cylinder and a second expansion cylinder to be expanded at two ranges, said expansion part connecting to an end surface of said slider at an end of said expansion part, said expansion part being expanded from said end surface of said slider perpendicularly in correspondence to said designated one of said board areas;
• an erasing part, said erasing part connecting to said second expansion cylinder of said expansion part, said erasing part staying close to a surface of said writing board to wipe off writing on said designated one of said board areas;
• and
• a suction part, said suction part connecting around said erasing part to suck dust obtained on wiping off writing on said designated one of said board areas,
• wherein said apparatus has an automatic control system remotely controlled by a control panel.