Along with the technological development, more and more realms need discharge or current velocities of the convection proceed precision control, The particularly modern medical treatment realm loses the liquid current velocity to the vein to want with the nursing of flow to beg more and more high. This device is to adopts a 89C51s enter the type electrical engineering squeeze to lose the liquid control system liquid intravenous drop speed. Combining the adoption infrared ray light fax feels machine examination intravenous drop speed,respond quick,the sensitivity is good. Combine detailed introducing the single electrical engineering control system that a machine constitute, and pass to expand 8255 design for completing keyboard with realistic electric circuits. That system can also pass the slice of RS-232 constitutes with place of honor machine the lord from the control network, realizes to unify the control. Combine to have the liquid of lose over the friendly bubble reports to the police to wait the function, using the vivid convenience.
Keywords: 89C51s, the type of stepping, the sensor,8255, RS-232
