The real-time operating system that is embedded in the microcontroller code memory is powerful, which can measure current and voltage values then calculate leaf area according to user selected leaf shape and display the result in real time. Meanwhile, it can store all of the current, voltage, and measured leaf area values in data memory for later requests. Also the data may be uploaded to the computer usingUSB interface in real time or later whenever user needs. The operation is so easy and user-friendly.