Microcontroller-based human stress detection system using fuzzy logic

Abstract

This research presents a working prototype of human stress detection device capable of measuring human stress level perhaps also for autistic children. The device records human physiological signals in order to determine the mental stress level. High stress levels may be dangerous especially for certain individuals such as autistic children who are unable to express mounting levels of stress. The autistic children can have frequent tantrums and seizure activities without any visible signs or symptoms, making this device a useful tool for parents and doctors to anticipate any harmful behaviours of autism. This research focuses on the hardware and software development of a low cost microcontroller-based stress detection system prototype. The prototype was designed using Arduino Mega platform and tested with 35 clinical patients. The data from two sensors is fed to the microcontroller using its two analog input pins and the sensor data is sent to the fuzzy logic module which is pre-programmed into the microcontroller for further processing. The output of the prototype is displayed on the LCD module connected to five digital pins of the microcontroller. In addition, three LEDs are connected to three digital pins of the microcontroller which light up in accordance with the stress levels. In order to test the developed system, an experiment was designed which requires subjects to perform mental calculations to solve arithmetic problems. The experiment involves three phases: low stress phase (P-1), medium stress phase (P-2) and high stress phase (P-3). The results showed that the prototype measures the stress levels with high degree of accuracy and efficiency. Apart from that, the results also highlighted that the stress neither depends on age nor gender.