Another common need is to track people. One market for this is healthcare, where a system of beacons and associated infrastructure enables tracking of patients or nursing home residents. It can also report how long they have been at that location and, with the accelerometer, how much have they been moving. The system can signal an alert if the person has been immobile for too long, for instance in the patient’s bathroom, which would suggest that they might need a welfare check. Enterprise applications include tracking event attenders, to collect data on traffic flow; or construction sites, where tracking personnel can be a key part of the worker safety program. In hospitality, such as on cruise ships and in amusement parks, beacons can be used by family members to maintain real time location information, so that parents can monitor their children and for management to track where guests are spending their time. At present, of course, an important application of people tracking is contact detection and tracing. The beacons, with their LEDs, can implement a proximity warning alerting the wearers that they have been too close for too long. They can be programmed to illuminate after some number of seconds or minutes when the wearers have been within two meters of each other, calling attention to the fact that appropriate social distancing is not being practiced. In addition, the beacons can keep a contact log recording the other beacons they have heard and how many minutes they were in proximity. This enables the contact tracing that can be important in reducing transmission of disease.