Wireless sensors to monitor bridge stress

    A wireless system for monitoring bridge integrity will transmit minute-by-minute updates and will cost as much as one-hundredth the amount of wired network.
    The sensors will be made up of four flexible layers and will be less that 5 millimeters thick. The different layers will measure parameters, store energy, transmit the data, and harvest energy from ambient light and radio waves. The sensors will be strong and self-adhesive and will require no wires or batteries since they will be powered by harvested energy.