Most conventional systems rely on switch closures triggered by running wheels, infrared beam-crossings, or burglar-alarm motion detectors. Such systems can be cumbersome to set up and run, and in some cases can be relatively insensitive. Big Brother tracks the distance travelled by each monitored animal using video cameras, reporting distance for each animal once per minute. The resulting data can be analyzed and viewed by the Big Brother Analysis Program. Or for long-term monitoring for circadian biology, records can be imported into ClockLab, the Actimetrics program for the field of circadian analysis.