Design of automatic onion drying machine using tray dryer system based on Arduino uno

One of the agricultural commodities in Indonesia which is quite large is onion. Shallots are agricultural commodities that are easily damaged, such as softening, wrinkles, porous, rotting, sprouting, and fungal growth. Damage to shallots causes a decrease in quality and selling value. Therefore, proper post-harvest handling is needed. One of them is in the drying process before storage, marketing, and processing. The use of an automatic drying machine using an Arduino Uno-based tray dryer system is one solution for the onion drying process. This drying machine is equipped with a temperature sensor that will send a signal to the microcontroller and proceed to the solenoid. At a certain temperature, the stove will turn off and on automatically. The machine is also equipped with a timer system so that the production process will get the same results. The most suitable temperature for the shallot drying process is 45ᵒ-75ᵒ C. Drying with a temperature below 45℃ will cause damage to the shallots because the fungi and microbes are still alive so that it can reduce the quality. Drying at temperatures above 75℃ can cause poor physical and chemical structure due to high heat transfer.