In this study, we designed a system that senses bed pressure levels and provides alarms for bed exit and prolonged bed rest; the system uses pressure sensors, a single-chip microcontroller, and a computer. The designed system enables reducing bed exit falls due to muscle weakness among hospitalized patients, preventing pressure injury among patients restricted to prolonged bed rest, preventing wandering behavior among patients with dementia, and reducing the workload of nurses. Furthermore, the system can serve as an adequate substitute in situations in which 24-hours monitoring is impractical; additionally, it is a low-cost alternative to existing alarm systems. Therefore, this alarm system can be adopted as common medical-care equipment for hospitals and nursing homes.