Researchers at MIT's Computer Science and Artificial Intelligence Laboratory have created a device that can read human emotions using wireless signals. The EQ-Radio reads subtle changes in breathing and heart rhythms to figure out if a person is happy, excited, angry or sad. The device measures heartbeats like an ECG monitor with a margin of error of 0.3 percent. It then analyzes the waveforms within each heartbeat to determine the person's emotion. "Our work shows that wireless signals can capture information about human behavior that is not always visible to the naked eye," project lead Dina Katabi, who co-wrote a paper on the topic with PhD students Mingmin Zhao and Fadel Adib, said in a statement Tuesday.