MITes (MIT environmental sensors) are low-cost, wireless devices for collecting data about human behavior and the state of the environment. Nine versions of MITes have now been developed, including MITes for people movement (3-axis accelerometers), object movement (2-axis accelerometers), temperature, light levels, indoor location, ultra-violet light exposure, heart rate, haptic output, and electrical current flow. MITes are being deployed to study human behavior in natural settings. We are also developing activity recognition algorithms using MITes data for health and energy applications. (A House_n Research Consortium Initiative funded by the National Science Foundation.)