Review on ELEPOWSTAR Motion Detector Alarm: 500ft Wireless Doorbell for Home Security System, Shops, Offices, Factories by Jordan Weakland

We bought this motion detector to prevent others from sneaking up on us from behind. Our office has many large displays and the back wall consists of floor to ceiling windows with street access. Countless times we've had the feeling that people would stare into the office or be startled when someone unexpectedly showed up at 3am. It definitely reduced the primal anxiety that comes with an open back. I only gave 4 stars as most of the chimes are too long. As well as being able to change the volume and beep, there are DIP switches in the sensor that change the detection time and whether the blue light turns on when motion is detected. Apparently you can connect more than one sensor to the base unit. The base plugs directly into an outlet and the sensor can be powered by 2 AA batteries or connected to a USB outlet with a micro USB cable.