Abstract

• Most of researchers and hobbyists who measure the distance between observer and object are used the ultrasonic sensor and then, they determined the distance by using the speed of sound wave of 340 ms-1 . They assumed that the speed of sound is constant at any time and at any local weather situations. But, in the point of view of Physics, the speed of sound is not constant and it depends on some parameters of weather conditions such as temperature and humidity. In this research, the distance between the observer and the obstacle is observed by programming with constant speed of sound as well as with the speed of sound depending on the temperature and humidity. The ultrasonic sensor, DHT22, OLED and ESP32 are mainly used to determine the distance. The calculation of the current speed of sound is based on the temperature and the humidity obtained from DHT22. The distance measured with constant speed of sound and that with calculated speed of sound are displayed on the OLED. The values of distance measured are directly uploaded to Excel spreadsheet using PLX_DAQ software. The comparison of distance measured with constant speed of sound and that with the speed of sound varied due to temperature and humidity is observed on Excel.