A sensing system for sensing conditions or characteristics associated with a process or thing. The sensing system includes one or more energy converters and a sensor, which are coupled to the process or thing. A node is coupled to the sensor and the energy-converter, and the node is powered by output from the energy converter. In a more specific embodiment, the node includes a controller that implements one or more routines for selectively powering a wireless transmitter of the node based on a predetermined condition. The predetermined condition may specify that sensor output values are within a predetermined range or are below or above a predetermined threshold. Alternatively, the predetermined condition may specify that electrical energy output from the energy converter is below a predetermined threshold. A remote computer may be wirelessly connected to node and may include software and/or hardware that is adapted to process information output by the sensor and relayed to the computer via the node.