With this configuration we test the absorption of energy by the device with all the sensors working in order to give a quantitative information for the autonomy of the device itself. In this system, the current is absorbed by different components. The microprocessor absorbs, without other loads, 48 mA, instead, each of the infrared sensors 33 mA, 3 mA for the ultrasonic sensor. The current absorbed by the whole system is equal to 117 mA, then, using a simple 9 V commercial battery with a capacity of 1200 mAh, our ETA has an energetic autonomy of more then 10 h.