This invention relates generally to monitoring systems and more particularly concerns devices and systems used to monitor patients the presence and absence of a patient from a bed, chair, etc. The preferred environment in which the instant invention would be used would be a hospital or other care giving facility, wherein patients who are at risk of falling might left unattended while they are seated or lying. According to a first aspect of the instant invention, a microprocessor-based patient monitor is disclosed which includes a loudspeaker that emits alarms synthesized by the microprocessor. The microprocessor synthesizes any one of multiple alarm sounds under software control and activates and deactivates the alarm in response to the electronic signals received from an attached sensor and a user interface.