ENGINEERS have developed a robot that can detect whether people are wearing a mask to guard against COVID-19 and, if not, politely remind them to put one on. The feature is an upgrade of Pepper, a 120 cm (47 inch) high robot with human-like features that is already in operation in some countries welcoming visitors to shops, exhibitions and other public spaces. Pepper's camera scans the faces of people approaching it, and if it detects the lower half of their face is uncovered, it pronounces the phrase: "You have to always wear a mask properly." If it sees that the…