Design and Implementation of the Automatic Coffee Drink Mixing System Based on Total Dissolved Solid (TDS) Level

Coffee is a beverage ingredient that is not only famous in Indonesia but also famous throughout the world. It is because ground coffee or brewed coffee has a distinctive aroma that other beverage ingredients do not have. Roasters, brewers, and baristas need data regarding coffee extraction to measure and control the coffee extraction level so that ordinary people who do not understand the coffee extraction process can also know. With an automatic coffee maker system, the TDS sensor will become a parameter tool for the accuracy of the extraction value. Arduino Uno is a microcontroller based on Atmega328. The DS18B20 temperature sensor has a function to measure the temperature of the water and the temperature of the coffee grounds.Moreover, the relay functions for the pump motor, heater, and stirrer motor and supports this automatic coffee system. In this study, the sensor has tested, and the TDS sensor accuracy value was 99.987% compared to commercial TDS value gauges. The temperature sensor accuracy value DS18B20 for water is 99.996% and the temperature sensor accuracy value DS18B20 for coffee beans is 99.995%. The test results show that when the temperature is more significant than and equal to 88°C, the water pump motor will turn on, and the water pump motor will turn off when the TDS value is below the specified extraction range.