Hanging shelves and heavy mirrors on your interior walls require finding the wall stud. There are several ways of finding the wall stud by tapping with your finger or making small holes in the wall with a brad nail looking for it. To eliminate the guesswork and prevent putting several small holes in your wall, a better way is to use a Black and Decker stud sensor. The stud sensor locates studs accurately while moving it over the surface of the wall. The Black and Decker has indicator lights to alert you when you come to the edges of a stud.
Press down on the battery cover with your thumb and slide it off the stud sensor. The battery cover is on the lower front face and has a small directional arrow near the top. Insert two AA batteries into the battery compartment. Ensure that the positive end of each battery is at the "+" stamp on the battery compartment. Slide the battery cover back over the battery compartment until it locks into place.
Hold the stud sensor upright and flat against the wall. Press and hold the on/off button on the side of the stud sensor with your finger.
Allow the upper red light on the front of the sensor to illuminate. The stud sensor will beep once indicating that the sensor is calibrating itself. Once the lower green light illuminates, the stud sensor is ready to locate a stud. Take care not to release the button, or you will need to recalibrate it as before.
Slide the stud sensor slowly across the wall horizontally without lifting it off the wall. When you approach the edge of a stud the red light illuminates and the beeper sounds. Hold the stud sensor and mark the spot where it first encountered the stud edge with a pencil.
Move the stud sensor to the other side of the stud and hold it flat against the wall. Slowly slide the sensor horizontally across the wall in the direction of the stud of the stud you just marked. When the red light illuminates again, stop and mark the point on the wall with a pencil.
You should now have two marks approximately 1-1/2" apart (the thickness of a 2x4 stud). Measure the exact distance between the two pencil marks and divide in half to locate the center of the stud.