Wednesday, January 04, 2006


The search vehicle designed with stepper motors is quite suitable for the defense application. Generally these kinds of vehicles are used in jungles for searching the anti-social elements. The system can be called as autonomous, because the vehicle itself detecting objects and according to the position of the object the vehicle takes diversion either right turn or left turn automatically. Some times the vehicle travels in reverse direction also, this happens when the vehicle finds a huge objects like trees, rocks etc., infrared sensors are used and they are arranged at front side of the vehicle.

For this purpose three sets of sensors are fed and each set contains two IR sensors. Two sets of sensors are arranged at left and right sides of the vehicle and the third set is arranged at middle of the vehicle. From each set, IR signal is delivered through one sensor like a laser beam, whenever the object interrupts the beam, the signal is reflected and this reflected signal is detected by another sensor. The outputs of all the three sensors are fed to Micro-controller, and according to the interrupted signals received by the sensors, the controller circuit drives the stepper Motors. These Motors drives the vehicle in different directions. For example, whenever the right sensors are interrupted, the vehicle takes left turn and moves in forward direction. Similarly if the left sensor is interrupted, vehicle takes right turn. Whenever the middle sensor is interrupted, vehicle moves in reverse direction up to certain distance and takes right or left turn.

The vehicle is called as search vehicle, because this vehicle is equipped with wireless video camera for collecting and transmitting the video images to the nearest monitoring station. At the monitoring station a small television set is used, so that presence of a person in the forest can be identified at monitoring station

In addition to the above an LDR is also used as a light-sensing device, and it is interfaced with the trigger circuit. The idea of using this circuit is to energize the vehicle headlamps automatically whenever the natural light disappears, with the help of this auto lighting system, during the nighttime also images can be transmitted. The output of the trigger circuit is used to drive the relay and this relay contact is used to energize the headlamps. Provision is made such that during the day time these lights remains in off condition.


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