Abstract: A mobile detection system for detecting a fire, gas leak, intruder, or other abnormal condition in a house or an office, and for alerting a central monitor, fire station, police station, or an occupant who is away from the house or office. The mobile detection system comprises a self-propelled movable robot having sensors located thereon. A monitor receives signals from the robot and alerts an authorized user accordingly. An automatic communication control unit includes a telephone transmitting unit for automatically calling an appropriate party in response to a signal from the robot and transmits commands to the robot from an authorized calling party. A radio frequency remote controller for remotely controls the robot. The robot is specifically capable of navigating throughout a house or an office while using its sensors to detect abnormal conditions.