By Mary Catherine O'Connor

Oct. 30, 2006—Workplace stress can make people do desperate things. Five years ago, Tim Stallard, a concrete engineer with the Michigan Department of Transportation (MDOT), was so frustrated by the poor performance of a wired temperature sensor he was using to track the hardness of curing concrete that he snagged a wireless indoor-outdoor temperature-monitoring system from his house, buried one of the sensors in a slab of freshly poured concrete and tested how far from the device he could walk before losing the signal. When the signal held for a good 30 feet, he knew he was onto something.

Stallard decided to search for an RFID vendor able to develop a wireless version of the wired sensors used conventionally to track the rate at which concrete cures. "The first few [RFID] companies I called thought I was nuts," Stallard recalls. "But when I called Identec Solutions, vice president of engineering Barry Allen responded by saying, 'Gee, I don't know, maybe it could work.'"



Allen sent a test kit to Stallard that included some Identec Solutions i-Q tags and a handheld interrogator to program and read the tags. These were battery-powered, came with an integrated temperature sensor and could operate in the ultrahigh-frequency (915 MHz) range. Stillard buried the tags and found that they worked. He could track them individually and take periodic temperature readings. He could even write data directly to the tags, such as assigning tag numbers or noting their location or depth within a slab of concrete.