The alarming rate of insecurity of lives and property globally is of great concern to all and sundry. Burglary is one of the most common criminal activities that is causing significant financial and emotional damage in local environment and households, several methods and devices have been developed to overcome this problem. The use of burglar alarm systems as a means of enhancing security cannot be overemphasized as safety of human lives is as important as food, clothing and shelter. Though several security alert systems have been invented in the past, there is still need for more efficient devices to ensure the reduction of insecurity of lives and property to the barest minimal. Hence, the need for innovative devices capable of mitigating this menace of insecurity especially in homes. This work is the development of a security alert system capable of effectively detecting an intruder, after which the security light is turned on, alarm is triggered and an automated voice is played through the speaker depending on the mode of operation the device is switched to. The components of the developed Security Alert Device are: Ultrasonic Sensors, Power Supply Circuit, Microcontroller Circuit, Speaker, Buzzer, Security Light and SD card Module. The device was tested after coupling and it perform excellently, also the overall cost was far lower than the existing price of similar devices in the market.