The present study is aimed to analyse the relationships of human responses to sudden changes in visual or hearing stimulations with respect to the age. As the accuracy of measurement of the time interval is significant in the study of human response, a microcontroller-based time measurement system is designed and developed with a resolution of 1 µs. The hardware of the device takes care of the generation and management of the clock through I/O ports of the microcontroller, while software captures and computes the response time. The effect of age on human responses to both visual and hearing stimuli was studied, and the natures of both the responses were compared. The results were analysed to determine the characteristics of human responses and the relationship between human response, type of stimulus, and age. It was shown that the human visual and hearing response-times increase with age, and the hearing response is faster than visual response.