The ANTI COLLISION DEVICE system works on the principle of retro-reflective infrared waves. It consists of an emitter and sensor module and a special reflector. The emitter emits the infrared waves in the direction of the reflector which reflects these infrared waves back and activates an alarm signal and stops reduces the speed of the crane. Thus if the two cranes are away from each other the reflected waves will not reach the sensor and the cranes operate normally. The sensing distance is specially designed for the crane application and is suitable for the continuous duty.