If these walls could talk...

Scientists at the University of Illinois Urbana-Champaign have developed a "smart brick" which could monitor a building's health and save lives. The brick is a blend of sensor fusion, signal processing, wireless technology, and basic building materials that will report building conditions to a remote operator.

The prototype has a thermistor, two-axis accelerometer, multiplexer, transmitter, antenna, and a battery hidden inside a brick. It can monitor a building's temperature, vibration, and movement. According to Chang Liu, a U of I professor of electrical and computer engineering, the sensor circuitry can also be embedded in concrete blocks, laminated beams, structural steel, and other building materials.

The battery charges up via an inductive coupling as used in electric toothbrushes. The researchers are using off-the-shelf components to make the bricks. "Ultimately, we would like to fit everything onto one chip, and then put that chip on a piece of plastic instead of silicon," says graduate student Jon Engel. Silicon is brittle and can easily crack or break. "Sensor packages built on flexible substrates would be more resilient and offer additional versatility," says Engel. "For example, you could wrap a flexible sensor around iron reinforcing bars that strengthen concrete and monitor the strain."

Scientists have already developed such sensors by depositing metal films on flexible polymer substrates. Called "smart skin," the sensor material can wrap around any surface, such as a robotic finger. "While a typical tactile sensor only measures surface roughness, our sensor material can determine roughness, hardness, temperature, and conductivity," says Liu. Although the skin is not wireless, scientists are perfecting the analog-to-digital conversion process for wireless links. However, the smart bricks themselves are wireless. Besides keeping tabs on building health, applications include monitoring nurseries and senior homes, and creating interactive smart toys that respond to a child's touch.

Professor Chang Liu and his team developed a "smart brick" that could monitor a building's health and save lives.