Details: There are two tips to ensure the wall scanner never trick you again 1. Go slowly: To be effective, stud finders need to be properly calibrated. First, place yours on the wall and turn it on — you can usually do this by holding in a button. Let the stud finder read the density of the material (this will only take a second or two and you will hear the sound of " beep"), then slowly move it from side to side. Go back and forth over the wall a few times, starting from a different spot with each pass. Mark each stud you discover with a pencil. We recommend finding three and using a tape measure to make sure they are the same distance apart. This will help you avoid false positives. 2. Always double-check: After you have marked your studs and where you want to drill your holes, you should use something to poke into the wall to ensure you actually marked a stud. We would recommend doing this by hand, rather than using a power tool, as you will have a better feel for what’s inside the wall. You can also tap a small nail into the wall; get past the drywall without the nail “falling in” and you’ve found a stud. The last thing you should do before drilling is poke a little hole to the left and right of where you want to drill and make sure you are still on the stud. This will ensure you are centered on a stud, and not just clipping its side (and possibly hitting electrical wiring).