Microcontroller-Based Coffee Acidity Detection Design

In this paper, a coffee acidity detector with a coffee acidity sensor, an AT89C51 microcontroller, and an A/D converter is designed to detect coffee acidity, and it also has an audible and visual alarm function. This detector can not only detect the coffee acidity in a specific environment, but also set different thresholds by different environments, and give an audible and visual alarm when the coffee acidity in the air exceeds the set threshold value. The design is divided into two parts: Software design and hardware design. The hardware design part is to use the MQ303A coffee acidity sensor to first measure the coffee acidity in the air, and then convert it into a voltage signal, and then convert it into a digital signal with an A/D converter, and then transmit it to the microcontroller system. Finally, the microcontroller system and the corresponding peripheral circuit to perform signal processing, liquid-crystal display (LCD) if the caffeic acid value exceeds the threshold will produce an alarm. The software design part of the program adopts a modular design approach so that the functions of each subroutine are relatively independent and easy to debug and change. The circuit can be divided into a minimum system circuit for the microcontroller, an audible and visual alarm circuit, an A/D converter circuit, a keypad circuit, and an LCD circuit.