Something there is that doesn't love a wall. Like me when I have to hang heavy pictures or large mirrors. I have no trouble with little pictures and photographs. Those I stick up with a variety of clever adhesive-backed hooks and special picture-hanging putty.

But knickknack shelves, bookcases, sculpture, framed genealogical diagrams, swords, chain mail and gun racks -- all of these require locating invisible studs lurking behind plaster board or paneling. By studs, I am referring not to male denizens of singles bars but to 2-by-4-inch, 8-foot-tall spruce or pine boards that form the rough interior framework on which wallboard or paneling is nailed.

The classic low-tech way to find a stud is by rapping on the wall. This produces a thumping, which, when it becomes a thudding, indicates a change in density, supposedly signifying the presence of a stud less than an inch beyond one's knuckles. A delightful bit of folklore this. The only sure result is sore knuckles and addled folks in the next apartment.

The trick is not merely to find the hidden stud but the stud's center, an incredible feat of marksmanship given that the facing edge of a 2-by-4 is really only 1 3/4 inches wide. The next choice is an inexpensive magnetic stud finder. But this device is only slightly less maddening than rapping, particularly when it locates broken or off-center nails and bits of wire.

Using these methods on your stud-quest will eventually get your pictures hung, but first you'll have to punch numerous "test" holes, suffer a loss of self-esteem and make a considerable investment in spackling compounds and wood putty.

So it was with some bemusement, and not a little skepticism, that I purchased the Stud Sensor, a $25 electronic device whose "advanced solid-state technology" promised to pinpoint invisible framing without the usual mutilation of walls or hands. One part of my psyche, however -- that reptilian or macho region of my brain -- resisted the idea that such a device should even be necessary, much less welcome in my toolbox.

Didn't my father and his before him find studs without benefit of electronics? Hadn't I always used traditional methods to hang my framed treasures? An electronic stud finder seemed not merely wimpy but a threat to my manhood.

The traditionalist in me would, in fact, love to snort derisively that the only good stud is one found with blood, sweat and beers. My rational side, however, is happy to report that the Stud Sensor is a delight to use. About the size and weight of a TV remote control and powered by a 9-volt battery, it's easier to use than a pocket calculator.

The Stud Sensor works not by magnetism but by detecting variations in certain electrical properties of matter known as the "dialectric constant." Stud Sensor is a perfectly sensible tool. My father would have loved it.

He would also have been tickled to own Measure Mate, an electronic tape measure. It won't replace an ordinary tape measure, but it can surely make life easier for real estate agents (every third person in the Washington area, it seems), builders, appraisers and anyone else who must frequently estimate room sizes.

Measure Mate, which is about the size of a large bar of soap, has an inch-long- by-half-inch-wide liquid crystal display (LCD) screen on the front and a button on the top. When you place the gadget against a wall and press the button, the device fires a burst of ultrasound in the opposite direction. Like a bat, Measure Mate then computes the linear distance by gauging the time it takes the sound to return. Unlike a bat, the LCD screen shows a readout in feet and inches.

Measure Mate runs on a 9-volt battery and has a range of 2 to 35 feet. It rounds off measurements to the nearest half-inch and is, says the maker, 99 percent accurate.

There are several things it won't do -- like measure the distance to small objects or bounce its signal off drapery and other sound-absorbent materials. Nor would I use it to measure precise fittings. But I found it a whiz for getting instant estimates of square footage for painting, wallpapering and flooring, and it also works outdoors. Better yet, it's fun to use.

At $88.45 from its manufacturer (ETEC, 3028 Commander Dr., Carrollton, Tex. 75006), or about $10 more locally from the Sharper Image, it's a rather expensive replacement for a tape measure if you take room measurements only now and then. But if estimating interiors is part of your daily work, the device could become an indispensable piece of technology. It's also, I'm happy to report, much easier to handle than a bat. ::