Philips Hue announces a $40 motion sensor

Philips Hue is expanding its line up of smart light devices with a motion sensor. This one is pretty straightforward — when you walk in front of the sensor, your Hue lights will turn on. What’s different from other motion sensors? It works on battery, so you can put it anywhere around your home, such as the corner of a hallway, a bathroom or a garage. Philips says the device is supposed to work for two to three years with two AAA batteries. It costs $39.95.