This paper deals with Mini Radar. Mini radar is an prototype of military based surveillance radar. It is implemented using arduino Mega board. The main reason for the use of arduino board was its low cost and its open source nature. Mini radar basically is an autonomous feedback system in which if an intruder enters the surveillance zone it is detected by the ultrasonic sensor of the radar, the sensor communicates to the vehicle(robo) via arduino about the position and the angle of the intruder to the defense vehicle. Knowing the position and angle of the intrusion. The defensive vehicle marches in the direction of intruder and explodes reaching in the vicinity of intruder