International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 06 | June 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 754 Automatically Controlled Solar Tunnel Dryer using Arduino for Sapota Mr. Aniket S. Mane-Deshmukh 1 , Mr. Deepak R. Patil 2 , Mr. Sunit S. Kore 3 , Mr. Vinaykumar N. Patil 4 , Prof. S. B. Mali 5 , Prof. D. P. Durgade 6 1,2,3,4 Student of Department of Agricultural Engineering, Dr. D. Y. Patil College of Agricultural Engineering and Technology, Talsande, India. 5 Assistant professor of Department of Agricultural Engineering, Dr. D. Y. Patil College of Agricultural Engineering and Technology, Talsande, India. 6 Assistant professor of Department of Electronics and Telecommunication Engineering, SBGI, Miraj, India. ----------------------------------------------------------------------------------------------------***--------------------------------------------------------------------------------------------------- ABSTRACT:- Sun drying of agricultural products is the traditional method employed in most of the developing countries. Sun drying is used to denote the exposure of a commodity to direct solar radiation and the convective power of the natural wind. Solar drying can be considered as an advancement of natural sun drying and it is a more efficient technique of utilizing solar energy due to its renewable, environmentally friendly technology. Nowadays drying agricultural products have great attention and there are various methods of drying fruits, vegetables such as dehydration, canning etc. due to this the quality of such product is degraded so solar dryer is used to avoid wastage, increase the productivity of agriculture, also the production in terms of quality and quantity. This project describes a controlled environment which is suitable for small scale agricultural products drying process within a closed chamber, using Arduino. To start with, the sun rays are used to internally heat the fruit to remove the water content within the agricultural products. Then to maintain the humidity below a specified level, exhaust the humid air out of the chamber. Arduino is used to control the functions of heating, controlling the speed of exhaust fan and giving time indication & maintain constant temperature throughout the chamber. The graphs of time versus drying process obtained show that the automatic drying unit designed has worked as per the expectation by consuming less time compared to conventional drying process. Keywords : Arduino, Sensor, Foldable Solar Dryer, LCD Display. INTRODUCTION Drying is an excellent way to preserve food and solar food drying is an appropriate food preservation technology for a sustainable world. The high moisture content in fresh agricultural product (produce) is the basic cause for spoilage. If water is removed, then the shelf life of produce increases. Traditional open sun drying methods often yield poor quality, since the produce is not protected against dust, rain and wind, or even against insects, birds, rodents and domestic animals while drying. The solution of all these problems is the use of solar dryer instead of open sun drying. Solar dryers are the devices that use free solar energy to dry agro products. The studies indicate that cost of drying with solar energy is only one-third as compared to the cost using a dryer based on conventional fuels. Adequate drying helps to preserve the flavor, texture, and color of the food, which leads to a better quality product. In India, sapota is cultivated over an area of 156.1 thousand hectares with annual production of 13.08 lacs MT [6]. Sapota is widely cultivated in Gujarat, West Bengal, Karnataka, Andhra Pradesh, Maharashtra and Tamil Nadu. It is highly perishable fruit with moisture content of 70- 80% which can be reduced down to 10% by drying in order to increase the shelf life [3]. Mostly used methods for drying agricultural products like Sapota are canning, osmotic dehydration, microwave drying, oven drying, vacuum drying etc., due to this the quality of such product is degraded so solar dryer is used to avoid wastage, increase the productivity of agriculture, also the production in terms of quality and quantity. Different food types require different temperature for drying conditions in order to maintain their quality. In solar tunnel dryer we cannot control various drying parameters like temperature, relative humidity etc., due to that quality and quantity of product degraded. To overcome this problem we can use automatically controlled solar tunnel dryer. The temperature inside the solar tunnel dryer can be controlled by using microcontrollers like 8051, PIC, ARM, Arduino etc These solar dryers allow for controlled drying by managing the drying parameters such as moisture content, air temperature, humidity, and air flow rate. METHODOLOGY The design used for agro products drying chamber needs the temperature to be controlled throughout the drying process by using solar energy. Variable temperature conditions during drying are harmful for agro