Social isolation is likely to be one of the most affected health outcomes for the elderly due to the COVID-19 pandemic especially for seniors living alone at home. Therefore, we seek to identify it based on detecting changes in the elderly such as malnutrition and lack of mobility. In this article we present our sensor monitoring system that was implemented for 15 days in the home of a 26-year-old student living alone as a first step to later deploy in the home of elderly people. Then, we present our results based on the data collected by sensors during the experiment. Our study showed the feasibility of automatic identification of the (1) meal-taking activity (shopping, cooking, eating and washing dishes) and (2) mobility (inside the home and the act of going out). These results are an intermediate step in assessing the social isolation status of the elderly based on these ADLs