University of Maryland electrical engineering researcher Mehdi Kalantari has developed a tiny wireless sensor that monitors and transmits minute-by-minute data on a bridge’s structural integrity that he estimates is one-hundredth the cost of a wired network approach.
wireless sensors are designed with less than five millimeters in the thickness, and are comprised of four thin, flexible layers. The SenSpot is built using four level of senses, the first detects and measures structural parameters, the second stores energy, the third transmits data to central computer for analysis, and the outer layer harvests energy from ambient light and radio waves.
The great benefit of the wireless SenSpot is the capability to quickly trigger an alarm, to give early warning to bridge users or the government authority body/department that dealing with bridges and transportation.
Kalantari added that the SenSpot sensors require no damaging drilling into the bridge structure, eliminating high maintenance cost since the SenSpot harvest energy from ambient light and radio waves.
He says they should last at least a decade with practically no maintenance required. As they harvest energy from ambient light and radio waves, they don’t require any wires, batteries or dedicated external power source. With each unit costing about US$20, the total cost for an average-sized highway bridge needing about 500 sensors would be about $10,000.
In conjunction with the Maryland Department of Transportation, Kalantari has been testing the sensors by measuring the structural parameters of highway bridges in a real setting for almost a year. He says this has allowed him to optimize the device’s performance and energy consumption with the updated model smaller and 10 times more energy efficient than its predecessor. The field testing has also allowed him to track the bridges’ response to changes in weather conditions and traffic.
