A portable security alarm device includes a subscriber identification module (SIM) card operable to store an international mobile subscriber identity (IMSI) number and a related key that together identify the PSAD to a mobile telephone carrier, a cellular antenna, a GPS antenna and a GPS receiver communicatively coupled to the GPS antenna, a battery coupled to a sense circuit and operable to power the PSAD, a quick release switch operable to provide a signal indicating an occurrence of a one-stroke activation of the quick release switch by a user, an alarm operable to provide a loud warning sound, and a microcontroller including one or more processors and memory, where the microcontroller is operatively coupled to hardware components of the device, and where the microcontroller is configured with an operating system and software components, the software components including software configured to control the hardware components of the PSAD and perform operations.