The Health Department used wireless gizmos situated around the office that transmit signals to employees' mobile devices as they pass by. An app running on their smartphones interprets the data and delivers advice based on where they are. Employees who get up from a conference-room table might get an alert telling them to take the long way back to their desks. Walking past a water fountain five times prompts a suggestion that it's time to stop for a drink during the next go-around.