Design On Digital Honey Water Content Meter

Honey is complex carbohydrate saturated solution with high nutritional value. According to Chinese national requirements for physical and chemical properties of non- polluted honey, the water content should be less than 24% (changed by varieties).It is known that water addiction can reduce honey's nutritional value. Abbe-type refractometer and handheld refractometer are usually used to test the moisture content of honey. However, the abbe-refractometer is complex to operate and inconvenient to move, while the other one is of low precision. Both of them can not directly used to detect water content but read the refractive indexes before further calculation. In order to solve those problems, it is quite necessary to develop a digital honey water content meter with higher precision, and simple and convenient operating.The domestic and board researches show that the water content of honey has positive correlation with its electrical conductivity. When the water content is constant, the temperature has influence to electrical conductivity value. Based on that, a digital honey water content meter used microcontroller as controller and temperature compensation automatically is designed in this paper. The main tasks and results of this paper are as follows:(1) Mathematical model of water content, electric conductivity and temperature was established. And the result of validation proves that the correlation of mathematical model is 0.986.(2) The hardware system was designed in this paper. With a 8bit MCU as the control core and temperature sensor and conductivity sensor as the detecting elements, modules for inspired generating, conductivity detecting, temperature detecting, controlling and input & output of hardware system were designed in this article.(3) The software which was mainly written in C language was developed for the meter. It includes system's primary function and sub-functions for water content calculating, temperature detecting and processing, keyboard input, display and serial communication, etc.(4) The meter's software and hardware system debugging, production and measuring precision testing were executed in this design. The test results show that: temperature detecting error of meter is with in±0.1℃,conductivity detection errors is within±0.46μS/cm, water content measure error under normal temperature is in±0.5%.The digital honey water content meter based on electrical and used single chip as controller was first studied in this paper. This instrument can be used not only in honey purchase site, but also for online testing, and this design open up a new path for honey water content meter.