Environmental sensors may be used to measure temperature, humidity, etc. and report the results to a data collection device. It is possible to attach a radio device to a sensor so that the results can be reported wirelessly. However, both the sensor and the radio may require power source, such as a battery. This can increase both the manufacturing cost of the sensor and the lifetime maintenance cost of the sensor, so that the sensor becomes economically unfeasible for many applications. In addition, most radio circuits, by themselves may cost enough to make the sensor device economically infeasible, thus forcing users to rely on hardwired connections, which are in turn infeasible for applications requiring mobility.