Given the rapid increase in the aging population and the decline in birth rate, there is a growing demand for healthcare services. For the elderly who are living at home or in nursing homes, the bed is an integral part of their daily lives. The monitoring of physical activities in bed can provide valuable information of the status of an elderly person. This paper presents a Bed-Centered Telehealth System (BCTS), which uses the bed as the center of health data collection of telehealth systems implemented in homes and nursing homes. The core sensor of the BCTS is a soft motion-sensing mattress, WhizPAD. WhizPAD collects signals of physical activities in bed, which can be classified into events such as on/off bed, sleep posture, pressure distribution, movement counts, and respiration rate. The BCTS facilitates bed-related real-time monitoring, service reminders for caregivers, and a history of the user's data. Integrated with information and communication systems, caregivers can maintain awareness of elderly persons' daily activities and needs by using their mobile devices to access the WhizPAD and further provide the necessary care for them.