Solar fruit dryer using Vacuum tubes

 Solar Powered Automatic Fruit Drying System is a small scale fruit drying machine which is useful to dry different types of fruit. To make their usage  efficient,  they can be dried and preserved so that fruits can be used over a long period. Preserving fruits by drying is an important operation continued from prehistoric period. Infrared radiation can be used for grape drying purpose. It is unique process  and distinctly different from conventional or natural drying. The natural drying process has many drawbacks, such as requiring more time, large investment on space requirement and infrastructure for drying process, which cannot be afforded by a middle class farmer. The financial up gradation of a farmer in developed countries is possible by providing him the modern, automatic and low-cost fruit drying unit. This paper describes a controlled environment which is suitable for small scale fruit drying process within a closed chamber, using Microcontroller (89s52). To start with, the infrared light is used to  internally heat the fruit to remove the water content within the fruit. Then the air is blown inside the chamber to maintain the humidity below a specified level and exhaust the humid air out of the chamber. Microcontroller (89s52) is used to control  the functions of heating, blowing the air and giving time indication & maintain constant throughout the chamber. After the completion of the drying process a buzzer is activated for the duration of ten seconds to indicate the end of the drying process. A text message is also sent to the farmer through GSM to intimate him if he is not around. The expectation by consuming less time compare to conventional drying process. Solar panel is used to supply power to microcontroller.