Humidity sensors based on cluster assembled nanostructured carbon films in capacitive configuration have been fabricated and characterized. An electronic read-out system has been designed and implemented in order to measure the complex impedance of the device under operation. The sensor and read-out electronics provide a fully integrated and cost-effective system. Devices under test show a fast dynamic response and a good sensitivity compared to capacitive commercial systems. A linear response is observed for relative humidity in the range up to 70%. Hysteresis is practically absent in this range, while for higher values it is at most in the order of 2%.